Scan pattern referring to how radars steer their beam across their field of view to search for targets
A circular scanning radar uses an antenna system that continuously scans 360° in azimuth . The time required for the antenna to sweep one complete 360° cycle is called the scan rate. Scan duration is the number of “hits per scan,” or the number of pulses, reflected by a target as the radar beam crosses it during one full scan. Most pulse radars require 15 to 20 hits per scan to obtain sufficient information to display a target. The factors that determine the number of hits per scan the radar receives include pulse repetition frequency (PRF), antenna beamwidth, and scan duration.
Circular scan radars provide accurate target range and azimuth information. This makes these radars ideal for the roles of early warning and initial target acquisition. To accomplish these missions, the antenna generates a fan beam that has a large vertical beamwidth and a small horizontal beamwidth. Since elevation information will normally be provided by height finder radars, the size of the vertical beamwidth is not a limitation. This antenna scan allows the radar to scan large volumes of airspace for early target detection. Since early detection is the primary goal of early warning radars, accurate altitude and azimuth resolution are secondary considerations.
Circular scan radars designed for early warning transmit a radar signal with a low PRF. A low PRF allows sufficient time for the radar pulse to travel long distances, and return, before another pulse is transmitted. This gives the radar system a long, unambiguous range capability. Circular scan radars with low PRFs generally use long pulse widths in order to increase their average power and long-range detection capability. The scan durations of early warning radars are relatively long to provide the required “hits per scan” for long-range target detection. The plan position indicator (PPI) scope display is normally used with circular scan radar
In order to provide coverage for a large volume of airspace, the beamwidth associated with circular scan radar is relatively wide. This wide beamwidth, coupled with the long pulse width and low PRF, gives the circular scan radar a large resolution cell, especially at long ranges. This limitation can be exploited to mask force size and composition. However, as range decreases, the dimensions of the resolution cell decrease, and circular scan radar will begin to break out target formations.
Circular scan radars provide range and azimuth information for both early warning and acquisition roles. Modified circular scan radars that can also provide elevation information may be used for ground control intercept (GCI) roles. Two modified circular scan radars that determine range, azimuth, and elevation are the V-beam and the stacked beam.
The V-beam radar transmits two fan-shaped beams that are swept together. A vertical beam provides range and azimuth information. A second beam, rotated at some convenient angle, provides a measure of the altitude of the target.
A stacked beam radar employs a vertical stack of fixed elevation “pencil” beams which rotate 360°. Elevation information is obtained by noting which beam contains the target return. Range and azimuth information is determined in the same manner as in an early warning radar.
Linear scan is a method used by some radar systems to sweep a narrow radar beam in a set pattern to cover a large volume of airspace. Linear scans can be oriented in a vertical direction for height finder radars or in a horizontal direction, or raster, for acquisition and target tracking radars. Unidirectional linear radar scans in a single direction then begins its sweep all over again. Generally, linear scans offer excellent single-axis coverage, and the narrow beam offers enhanced azimuth and elevation resolution.
A helical scan is a unidirectional scan pattern that allows a “pencil” beam to search a 360° pattern. The antenna sweeps a 360° sector in a clockwise direction. After each complete revolution, the antenna elevation is increased. This scan pattern is repeated for a specified number of revolutions, in this case, three, 360° sweeps. At the end of the scan pattern, the antenna elevation is reset to the initial elevation and the scan is repeated. A helical scan pattern is commonly used as a target acquisition mode for radar systems with narrow vertical and horizontal beamwidths.
A bidirectional linear scan, such as a raster scan, sweeps both horizontally and vertically. A raster scan uses a thin beam to cover a rectangular area by horizontally sweeping the area. The angle of elevation is incrementally stepped up or down with each horizontal sweep of the desired sector. After the sector has been covered, the angle of elevation is reset to the original value and the process is repeated. The number of raster bars is set by the number of horizontal sweeps in the basic raster pattern. Shows a four-bar raster scan, which is normally associated with airborne interceptor (Al) radar.
A conical scan, or conscan, radar is generally used for precision target tracking. A conical scan radar employs a pencil beam of radar energy that is continuously rotated around the target. This circular rotation of a pencil beam generates a cone-shaped scan pattern with the apex of the cone located at the antenna. Thus, the name conical scan.
As the pencil beam rotates, the circular scan patterns overlap in the center. This creates a central tracking area that has a much smaller effective beamwidth than the rotating pencil beam. This results in a very precise tracking solution.
Since conical scan radars are designed for precision target tracking, these radars normally operate at high frequencies, high PRF, narrow pulse widths, and narrow beamwidths. The rotation rate of the pencil beam can exceed 1,800 revolutions per minute. This means that both azimuth and elevation data can be updated about 30 times per second.
The combination of conical scan and raster scan is called a Palmer-raster scan. A Palmer-raster scan uses a thin beam, employing a conical scan searching pattern, for a specific sector of airspace. With each sweep of the sector, the angle of elevation is incrementally stepped up or down. After the vertical sector has been covered, the angle of elevation is set at the original elevation and the process is repeated. The number of bars is determined by the number of vertical search scans.
The combination of a conical scan and a circular scan is called a Palmer scan. Palmer scans incorporate a circular scanning antenna to search the entire horizon while simultaneously performing a conical scan. If the radar antenna is also performing a unidirectional altitude search in conjunction with this scan, it is employing a Palmer-helical scan.
A track-while-scan (TWS) system uses a technique that allows a radar to track one or more targets while scanning for others. Radar systems with a TWS capability must be able to generate two or more distinct radar beams.
A conventional TWS radar employs two antennas that work with each other to perform the scan function . Each antenna produces a separate unidirectional beam. Each beam is transmitted at a different frequency. The vertical antenna generates a beam employing a vertical sector scan similar to height finder radar except the beamwidth is narrower and it scans at a higher rate. The horizontal antenna generates an identical beam employing a horizontal sector scan at a different frequency. The track function is accomplished in the area where the two beams pass through each other. A target that is within this center area is tracked and positional information on range, elevation, and azimuth is updated each time the beams sweep through the area.
The phased array radar is a product of the application of computer and digital technologies to the field of radar design. A phased array is a complex arrangement of many individual transmitting and receiving elements in a particular pattern. Common arrays include linear, planar, curved, and conformal, with linear being the most common. By using a computer to rapidly and independently control groups of these individual elements, a phased array antenna can, in effect, radiate more than one beam from the antenna. Multiple beams and computer processing of radar returns give the phased array radar the ability to perform the TWS function. The most common employment of the TWS capability of the phased array radar is in the air-to-air arena.
The number of individual transmitting and receiving elements is limited by the size of the radar antenna. The number of targets phased array radar can track is limited by the number of independent beams the antenna can generate. Many phased array radars, especially air-to-air radars, do not track and scan simultaneously, but rapidly switch between the two modes to overcome this limitation.
Modern TWS radars employ computer signal processing and complex computer algorithms to simplify the problem of target correlation. Air-to-air radar typically uses a raster scan to search a volume of airspace. In the search mode, the radar simply presents all targets detected in this airspace to the pilot on his radar display. In the TWS mode, the radar employs computer processing to figure out target correlation and update target information. This is done automatically, and the results are presented on the display.
In radar technology and similar fields, track-before-detect (TBD) is a concept according to which a signal is tracked before declaring it a target. In this approach, the sensor data about a tentative target are integrated over time and may yield detection in cases when signals from any particular time instance are too weak against clutter (low signal-to-noise ratio) to register a detected target.
The TBD approach may be applied both for pure detection when the tentative target displays a very small amount of apparent motion, as well as for actual motion tracking. In the first case the problem is considerably simpler, both in terms of the amount of calculation and the complexity of algorithms
The function of the antenna during transmission is to concentrate the radar energy from the transmitter into a shaped beam that points in the desired direction. During reception, or listening time, the function of the antenna is to collect the returning radar energy, contained in the echo signals, and deliver these signals to the receiver. Radar antennas are characterized by directive beams that are usually scanned in a recognizable pattern. The primary antenna types in use today fall into three categories: parabolic, Cassegrain, or phased array antennas. Additionally, the method radar antennas employ to sample the environment is a critical design feature of the radar system. The scan type selected for a particular radar system often decides the employment of that radar in an integrated air defense system (lADS). The process the radar antenna uses to search airspace for targets is called scanning or sweeping.
One of the most widely used radar antennas is the parabolic reflector.
The parabola-shaped antenna is illuminated by a source of radar energy, from the transmitter, called the feed. The feed is placed at the focus of the parabola, and the radar energy is directed at the reflector surface. Because a point source of energy, located at the focus, is converted into a wavefront of uniform phase, the parabola is well suited for radar antenna applications. By changing the size and shape of the parabolic reflecting surface, a variety of radar beam shapes can be transmitted.
The antenna depicted in Figure generates a nearly symmetrical pencil beam that can be used for target tracking.
Elongating the horizontal dimensions of the parabolic antenna creates a radar antenna called the parabolic cylinder antenna. The pattern of this antenna is a vertical fan-shaped beam. Combining this antenna pattern with a circular scan technique creates a radar system well suited for long-range search and target acquisition.
Elongating the vertical dimensions of the parabola creates a radar antenna that generates a horizontal fan-shaped beam with a small vertical dimension. This type of antenna is generally used in height-finding radar systems.
Another variation of the basic parabolic antenna includes using an array of multiple feeds instead of a single feed. This type of parabolic antenna can produce multiple radar beams, either symmetrical or asymmetrical, depending on the angle and spacing of the individual feeds.
A Cassegrain antenna uses a two-reflector system to generate and focus a radar. The primary reflector uses a parabolic contour, and the secondary reflector, or subreflector, has a hyperbolic contour. The antenna feed is located at one of the two foci of the hyperbola. Radar energy from the transmitter is reflected from the subreflector to the primary reflector to focus the radar beam. Radar energy returning from a target is collected by the primary reflector and reflected as a convergent beam to the subreflector. The radar energy is rereflected by the subreflector, converging at the position of the antenna feed. The larger the subreflector, the closer it can be to the primary reflector. This reduces the axial dimensions of the radar but increases aperture blockage due to the subreflector. A small subreflector reduces aperture blockage, but it must be positioned at a greater distance from the primary reflector.
To reduce the aperture blockage by the subreflector and to provide a method to rapidly scan the radar beam, the flat plate Cassegrain antenna was developed.
The fixed parabolic reflector is made up of parallel wires spaced less than a half wavelength apart and supported by a low-loss dielectric material. This makes the fixed parabolic reflector polarization sensitive. It will completely reflect one type of linear polarization and be transparent to the orthogonal polarization. The fixed antenna feed, in the middle of the moveable mirror, transmits a radar signal polarized to be reflected by the parabolic reflector. The moveable mirror is constructed as a twist reflector that changes the polarization of the radar signal by 90°. The signal from the feed is reflected by the parabolic reflector to the mirror, which rotates the polarization 90°. This rotation makes the transmitted signal transparent to the parabolic reflector, and the signal passes through with minimal attenuation. The radar beam can be scanned over a wide area by rotating the moveable mirror. A deflection of the mirror by the angle Ɵ results in the beam scanning through an angle of 2Ɵ.
The geometry of the Cassegrain antenna is especially well suited for monopulse tracking radar applications. Unlike the parabolic antenna, the complex feed assembly required for a monopulse radar can be placed behind the reflector to avoid aperture blocking.
PHASED ARRAY ANTENNA
The phased array radar is a product of the application of computer and digital technologies to the field of radar design. A phased array antenna is a complex arrangement of many individual transmitting and receiving elements in a particular pattern. A phased array antenna can, in effect, radiate more than one beam from the antenna by using a computer to rapidly and independently control groups of these individual elements. Multiple beams and computer processing of radar returns give the phased array radar the ability to track-while-scanning and engage multiple targets simultaneously.
Phased array radar uses the principle of radar phase to control the individual transmitting and receiving elements. When two transmitted frequencies are in-phase, their amplitudes add together, and the radiated energy is doubled.
When two transmitted frequencies are out-of-phase, they cancel each other.
Phased array radars use this principle to control the shape of the transmitted radar beam.
Phase relationships and antenna element spacing determine the orientation of the transmitted beam. For eg, antenna elements A and B are separated by one-half wavelength and are radiating in-phase, that is, when one is at the positive peak, the other is also at a positive peak. Since the elements are one-half wavelength apart, when the positive peak radiated by A reaches B, B will be radiating a negative peak. As the peaks propagate along the X axis, they will cancel each other out. The total radiated power along that axis will be zero. Along the Y axis, however, the positive peaks from A will add to the positive peaks from B, causing the total radiation along this axis to be at its maximum value. This type of array is called a “broadside array” because most of the radiation is in the direction that is broadside to the line of the antenna array.
The computer controlling the phase of the signal delivered to each transmitting and receiving element of a phased array antenna controls the direction and shape of the radiated beam. By shifting the phase of the signals between 0° and 180°, the beam sweeps. This is the basic means of producing an antenna scan. In addition, the amplitude, or power, of the signal applied to each element can be varied to control the sidelobes. This alters the shape of the beam which affects the range capability and angular resolution of the radar.
Depicts a variation of the phased array antenna, known as a planar array antenna. A planar array antenna uses transmit and receive elements in a linear array, but, unlike the phased array radar, the elements are smaller and are placed on a movable flat plate. The ability to simultaneously track several targets is one advantage of this type of radar.
The most important characteristic of any type of antenna is antenna gain.
Antenna gain is a measure of the ability of an antenna to concentrate energy in the desired direction. Antenna gain should not be confused with receiver gain, which is designed to control the sensitivity of the receiver section of a radar system. There are two types of antenna gain: directive and power.
The directive gain of a transmitting antenna is the measure of signal intensity radiated in a particular direction. Directive gain is dependent on the shape of the radiation pattern of a specific radar antenna. The directive gain does not take into account the dissipative losses of the antenna. Directive gain is computed using Equation
GD = Maximum radiation intensity / Average radiation intensity
The power gain does include the antenna dissipative losses and is computed using Equation
Power gain = max radiation intensity/ Radiation intensity of an isotropic antenna
The term isotropic antenna describes a theoretical spherical antenna that radiates with equal intensity in all directions. This results in a spherical radiation pattern. The power density for any point on an isotropic antenna is the radiation intensity and can be calculated by dividing the total power transmitted (PT) by the total surface area of the sphere,
Power density (Isotropic Antenna) = PT (watts)/ 4*Pie*r2 (Cm2)
The radiation pattern of an isotropic, or spherical, antenna would provide neither azimuth nor elevation resolution and would be unusable for radar applications. To provide azimuth and elevation resolution, a practical antenna must focus the radar energy. The power density of a practical antenna differs from the isotropic antenna only in terms of antenna gain (G).
Power Density (Practical antenna) = PT*G/ 4*pie*r2
The actual power gain (G) of a practical antenna can be calculated by using Equation
Ae= effective area of aperture
Lamda = Wavelength of the radar
The power density and gain of an antenna are a function of the antenna pattern of a radar system. Figures illustrate the antenna pattern of a typical parabolic antenna. Most of the power density of the radar is concentrated in the main beam. However, since the radar is not a perfect reflector, some radar energy is transmitted in the sidelobes. In addition, there is spillover radiation due to the energy radiated by the feed that is not intercepted by the reflector. Finally, the radar has a back lobe caused by diffraction effects of the reflector and direct signal leakage. Sidelobes and backlobes are all undesirable radiations that adversely affect the maximum radar range and increase the vulnerability of the radar to certain jamming techniques.
The recent article appeared in India Today, based on a decade old report triggered a series of debates about the capabilities of Tejas aircraft. So we decided to create an article comparing one of the world’s most dominant single engine fighter that is Gripen NG with Tejas.
The Gripen has American Engine, IRST and AESA radar made by an Italian-British company, missile launch rails made by an American company, Cockpit made by an Israeli company, many other foreign components and foreign weapons. Still the Gripen is called an Indegeneous Weapon nobody has any problem in buying Gripen. Because it is Gripen It is not HAL Tejas. In HAL Tejas apart from engine and Radar there is rarely anything that has been a foreign product. Still people say Tejas not indigenous.
Saab has been making aircrafts since the 1930s. They take 70 years to produce an aircraft like Gripen NG, we only take 30 years to develop an aircraft like Tejas. There is lot of problems faced from the start of the project and the western sanctions also affect the program still we managed to develop a world class fighter. 65% of Tejas is ingenuously developed. Tejas MK 2 will incorporate 90% indigenous tech and surely it can outperform Gripen NG in many areas. Gripen considered as one of the best multi role fighter in the world. Many defense analysts place Gripen inside the top 10 table. We must be proud of by our achievements and must support our great scientists.
The comparison between Tejas and Gripen is in the following 4 criteria’s
Both Tejas and Gripen incorporate a certain amount of stealth. Gripen uses 30% composites & Tejas uses 45 % composites. 90% of the surface of Tejas is made of composites. The RCS of Tejas not publically available. Tejas MK2 will contain 70% of composites surely MK2 will have a considerable advantage in stealth. Both Gripen and Tejas using Radar Absorbent materials and coating for reducing RCS.
RCS of Tejas = 0.5 m2
RCS of Gripen = 0.9 m2
So far as aerodynamics is concern, Gripen is an excellently designed plane which gives it a very good speed and long range. LCA Mk1 was considered to be a bit draggy but a lots of studies have been made to improve its aerodynamics is concern. Making LCA Mk2 1m longer is a part of Aerodynamic improvement process for better compliance of Area rule. There are some other aerodynamics changes which are coming in LCA Mk2. Study says that it will reduce drag by 8% and improve trans sonic acceleration by 20%.. So these aerodynamic changes should make LCA Mk2 a plane with very good aerodynamic characteristic.
For good turning performance wing loading should be low and thrust to weight ratio (TWR) should be high. Tejas has an advantage in both TWR and wing loading. The thrust-to-weight ratio of a combat aircraft is a good indicator of the maneuverability of the aircraft. So Tejas should have better turn rates than Gripen .Tejas shall be at a big advantage because of its light empty weight and should maneuver fast and probably can beat Gripen in close combat. Its small airframe makes it difficult for the enemy pilot to spot in a close combat. Tejas have an advantage of low wing loading also which should give it an edge at high altitude fighting. Some websites claims Gripen has superior Sustained turn Rate than any other aircraft anyway we are not considering it as a credible source. However airplane design always a compromise & both wing loading & TWR can be “adjusted” within some margins to enhance turning performance. We don’t know anything more about the specifications of Gripen to evaluate its maneuverability. Even though Tejas has better turn rates we consider both Tejas and Gripen almost equally maneuverable.
TWR Tejas = 1.07
TWR Gripen = 0.97
Wing loading Tejas = 247kg/m2
Wing loading Tejas = 283kg/m2
Gripen got very good radar, a gallium Nitride based radar. LCA Mk2 is also all set to get top of the class AESA radar till Uttam is ready with 150 KM range. Israel has offered ELTA 2052. Recently Thales has flight-tested active array radar built specifically for Tejas. The radar is based on the company’s successful RBE2 radar installed on Rafale fighter jets. With the latest Thales AESA radar MK1A can kick out any of its adversaries. But still lags behind Gripens GaN Raven radar.
Gripen also going to get a world class IRST in the form of Selex skyward G and tejas doesn’t have any IRST till now. With the help of GaN radar and skyward G IRST gripen can detect stealthy fifth generation fighter aircraft's at long distances.
In Electronic Warfare Gripen is the first aircraft which uses electronic warfare system based on gallium nitride technology, India and Israel are making EW for Tejas and has designed MAYAVI Ew suite for Tejas and work is on for better EW. India has got spectra configured for Indian requirement. If spectra technologies goes in LCA MK2 by the way of buy back clause, it will be superior to Gripen. If not, Indo-Israeli EW will catch up with that of gripen .
So far sensor fusion is concern; Gripen is a top class plane. India is also working on sensor fusion but how much effective that will be is not known. Here is an area where I see gripen is significantly out performing Tejas in current scenario. Gripens sensor fusion is only inferior to F35 , and nobody knows how good will be India’s own sensor fusion. In avionics Gripen is atleast a generation ahead than Tejas Mk1A. May be MK2 can catch up with Gripen NG.
Both Tejas & Gripen have very good targeting pod and weapons . India shall use Python, derby and Russian missiles along with Astra. Gripen uses AIM Series and Meteor missile. Meteor is a top class missile but new Israel claims I Derby can provide 80% of meteor performance. Astra 2 the desi meteor is under development can also be include in Tejas Mk2 weaponry. Both planes are neck to neck in A to A missiles but If Meteor is used, Gripen will have a superior edge. Both will have gun according to their requirement and both can use guided bombs. India has just tested SAAW bomb which will give LCA MK2 an edge in anti airfield strike capability.
Engine and Power
Both Tejas and Gripen deriving the power from same engine GE 414 with a Dry thrust of 62 KN and 98 KN in afterburner. However India is also working on indigenous kaveri engine with the help of Snecma France. New Kaveri engine is supposed to have same power as GE 414. LCA Mk1A has 13.2 M long which is 2 meter short in length of Gripen. Both planes have same g limits. LCA mk1As service ceiling is 16000 m which is higher than the 15240m of Gripen . This is because of low wing loading and will give protection to LCA against many short range and shoulder fire missiles and SAMs. MK2 may have even better service ceiling which will increase the advantage of MK2 over Gripen NG.
Gripen has better speed than Tejas which does not make a big difference. But the super cruising ability of Gripen gives it an advantage of Tejas Mk1A, but we can incorporate super cruise ability in Tejas MK2. However, supercruising uses more fuel to travel the same distance than at subsonic speeds but uses less fuel than afterburner.
Gripens Higher cruise speed allows pilot to surprise the enemy by approaching him from the rear, zone of poorest detection, and to avoid getting surprised by a slower-cruising opponent. It also allows the fighter to choose a time and place of engagement.
In the beyond visual range combat, super cruise capability increases range of the missile shot, and reduces the effective range of adversary’s missiles. If pilot decides to pursue a merge or a visual-range attack pass, its excess kinetic energy again allows it to dictate terms of the engagement. It can also offset a possible situational awareness disadvantage – knowing where the enemy is is of little use if you can’t engage him.
Super cruise is an area where MK1A lag behind Gripen.
Max Speed Of Tejas – mach 1.8
Max Speed Of Gripen – mach 2
LCA MK1A has 500 m take off distance (some sources says it is 700m). Gripen NG has a short take off distance of 400m which favors Gripen and it will reduce at least 15% in Mk2 so mk2 will have equal short take off distance.[Figures may not be accurate ].
Speed at sea level is also against Tejas compared to Gripen, Gripen got 1400 Km/H at sea level Tejas got 1300 Km/H. We believe things will change in Tejas Mk2 with better aerodynamic features Mk2 can catch up with Gripen .
The maximum takeoff weight (MTOW) of an aircraft is the maximum weight at which the pilot is allowed to attempt to take off, due to structural or other limits. MTOW is the heaviest weight at which the aircraft has been shown to meet all the airworthiness requirements applicable to it. Gripen has a MTOW of 16500 Kg Ideally it should be 2.5 times the dry thrust which comes around 15.62 tons but let us assume that it is 16.5 tons as stated in specification. LCA Mk2 uses the same engine so it should have an ability of 16.5 tons MTOW but let us apply that 2.5 factor rule. LCA Mk2 should carry atleast 15.62 MTOW. Now Gripen with 8 ton weight +3.4 ton fuel is left with 5.1 ton payload on plane. On the other hand LCA MK2 with 6.2 ton empty weight and similar fuel of 3.4 ton should left Tejas with 5.7 ton weight which compares favorably to Gripen.
Fuel fraction or propellant fraction, is the weight of the fuel or propellant divided by the gross take-off weight of the craft (including propellant). Fuel fraction of Tejas & gripen is almost similar. So far as range is concern, Tejas should have higher range as both planes are using same engine but Tejas being significantly lighter should have a longer range. But gripen has a considerable advantage in range. An aircraft with more and heavier load (Gripen) should have a smaller radius of action than the same one with less and lighter load (Tejas), due to higher fuel consumption at heavier weights.
Combat Radius of Tejas = 400 Km
Combat Radius of Gripen = 800Km
Why Tejas has less combat radius than Gripen even though both uses similar engines, this is a mystery.
Possible Reasons of Less Combat radius
Both planes are very good having their edge over others in different area. However, Tejas with its small size and very high T/W ratio offers many advantages as a platform. Gripen has significant advantage over Tejas in Avionics and sensor fusion and have slight advantage in weapons its almost similar in all other criteria’s. Tejas MK2 with better Radar, Smart Skin, and Internal Unified Electronic Warfare (Under development) can catch up with Gripen NG. Overall Gripen is the only 4th generation single engine aircraft which has a significant advantage over Tejas.
Why IAF looking for another single Engine Fighter
The major reason behind this is HAL said Tejas MK2 will not come before 2024; HALs engineers and scientists are busy with AMCA project. IAF can’t wait for another 7 or more years for Mk2.And the future technologies expecting in Tejas MK2 will not be a proven one and IAF don’t know how good it will be, it’s a logical choice to go for a proven technology rather than puzzling with indigenous solution and getting hands into theses advanced western techs will positively added up with AMCA ,one more thing is both Tejas and Gripen will come into Air force in the same time, if we avoid foreign single engine fighters we only get 8 -10 Tejas in a year otherwise IAF will get 8-10 tejas plus 8-10 gripen in a year that is significantly adding more number of jets in IAFs fleet, that what exactly IAF want now to deal with the dwindling squadron numbers. IAF interested in Gripen mainly because of the advanced Avionics, sensor fusion, net centric capabilities and Electronic Warfare.
Note:- This is our own views, it dont have any relation with IAF sources.
LCA Mk2 shall be very cost effective and offer India a platform to integrate its own weapon. It will have a lots of configuration options also. Once it is ready in next 5 years with Indian engine , Indian AESA, it will be a weapon very difficult for any other system to match and will give India an edge over any other rival in air combat. It will easily outclass anything china or Pakistan has. India can mass produce it and offer it to many friendly countries across the world including Vietnam, Indonesia, African countries and even to the countries like Brazil who are interested in Gripen. It will offer everything which Gripen offers. What India need at this stage is to expedite LCA Mk2 program and make it sure that it goes into production in as early as possible.
A rough comparison between J10 & Tejas
The J 10 started off as a Chinese attempt at reverse engineering a Pakistan bought US F-16. However it ended up being a modification of Israel’s Lavi multi role fighter, Lavi program was cancelled in 1987 in Israel due to threatening from US. China purchased the blue print from Israel and developed J 10.
The detail of J 10 is hardly available. From the available data it’s very clear that Tejas is not inferior to J 10. J 10 has advantage in weapon loads; range etc only because it is a bigger aircraft so J10 can carry more weapons.
Both aircrafts are pretty much maneuverable. One noticeable aspect of Tejas is its wing loading 247 Kg/m2 is much lower than the 381 Kg/m2 of J 10, which results in better agility. This low wing loading of Tejas gives better climb of rate & also gives good cruising performance cause it need less thrust to maintain the stable flight. This better climb rate is a give Tejas advantage in Himalayan regions. Heavier loaded wing is efficient in higher speed because it causes less drag but in overall performance level low wing loading offers better performance. Another advantage is a fighter with low wing loading can maintain better sustained turn rate (maximum turn an aircraft can achieve) aircraft with higher wing loading may have better instantaneous turn rate. So it is clear that in Himalayan regions a low wing loading Tejas can outperform a higher wing loading J 10 in most criteria’s.
Another important factor affecting the performance of Chinese J10 is the altitude of China's main airbases "along with the prevalent extreme climatic conditions seriously restrains the performance of aircraft, which reduces the effective payload and combat radius by an average of 50%." In other words, the lower density of air at high-altitude Tibetan bases prevents Chinese Air Force fighters such as the Su-27, J-11 or J-10 from taking off with a full complement of weapons and fuel. These aircraft would, therefore, enter a fight with the IAF at a severe disadvantage in the event of a conflict. The IAF, on the other hand, operates fighters in the Northeast from bases such as Tezpur, Kalaikunda, Chabua and Hasimara which are located near sea level elevations in the plains. This means "the IAF has no such restrictions and will effectively undertake deep penetration and air superiority missions in the Tibetan Autonomous Region."
Thrust to weight ratio of Tejas is 1.07, which is less compared to 1.15 of J 10. But it can be improved using a better power-plant. Overall the maneuverability is almost similar.
Both aircrafts are fitted with AESA radar, the capabilities of J10 B / J10 C is not available. According to some blogs “J10C is equipped with more advanced radar. It has a greater detection range than the J10 radar to simultaneously track 12 targets and against the ability of the six targets which pose the greatest threat” looks almost similar to Tejas AESA radar.
J 10C has better stealth features than J 10B. Chinese media calling it as a semi stealth fighter, but from our own research, it’s not going to be stealthier than Tejas, even though Chinese media claims it has a new technique to achieve stealth, and some of those claimed J10C is a threat to even F22. Whatever it is,their comparison of J 10C with F 22 is laughable.
Overall Tejas can give tough competition to J 10B and is slightly inferior to J10C, Tejas Mk2 with better aerodynamics and more stealth features, can catch up with J10C.
The primary purpose of radar systems is to determine the range, azimuth, elevation, or velocity of a target. The ability of a radar system to determine and resolve these important target parameters depends on the characteristics of the transmitted radar signal. This chapter explains the relationship of radar frequency (RF), pulse repetition frequency (PRF), pulse width (PW), and beam width to target detection and resolution.
A basic pulse radar system consists of four fundamental elements: the transmitter, the receiver, the antenna, and the synchronizer, or master timer.
The transmitter, through the antenna, sends out a pulse of RF energy at a designated frequency. The presence of a target is revealed when the RF energy bounces off the target, returns to the radar antenna, and goes into the receiver. The master timer measures the time between the transmission of a pulse and the arrival of a target echo.
RF energy travels at the speed of light (c) which is 3 x 108 meters per second. Target range can be computed by using the basic radar range determination equation.
Target Range = (measured Time * Speed of light)/2
Another useful measurement is the radar mile, which is the round trip time for an RF wave to travel to and from a target one nautical mile away. In simple terms the time required for a radar pulse to travel a distance of one nauticalmile and then return to the radar receiver. One radar nautical mile is equal to approximately 12.367 μs
Measured time = (Target Range *2)/ c = (1853 meters *2) / 300000000 = 12.367 Micro Seconds.
Radar timing is usually expressed in microseconds. To relate radar timing to distances traveled by radar energy, you should know that radiated energy from a radar set travels at approximately 984 feet per microsecond. With the knowledge that a nautical mile is approximately 6,080 feet, we can figure the approximate time required for radar energy to travel one nautical mile using the following calculation:
A pulse-type radar set transmits a short burst of electromagnetic energy. Target range is determined by measuring elapsed time while the pulse travels to and returns from the target. Because two-way travel is involved, a total time of 12.36 microseconds per nautical mile will elapse between the start of the pulse from the antenna and its return to the antenna from a target.
This 12.36 microsecond time interval is sometimes referred to as a RADAR MILE, RADAR NAUTICAL MILE, or NAUTICAL RADAR MILE
1 Radar Kilometer = 6.66 Micro Sec
The range in kilometers to an object can be found by measuring the elapsed time during a round trip of a radar pulse and dividing this quantity by 6.66. The range in nautical miles to an object can be found by measuring the elapsed time during a round trip of a radar pulse and dividing this quantity by 12.36.
A limitation on radar detection range is the concept of a second time around echo. A second time around echo occurs when a target echo associated with a particular radar pulse arrives at the antenna after another radar pulse has been transmitted. The radar master timer always assumes the target echo is associated with the last pulse transmitted. This makes the target echo ambiguous in range.
Example: - Radar pulse A takes 372 microseconds to travel to the target and return. Using the range determination equation, actual target range is 30 nautical miles (nm). However, before the target echo returns to the antenna, radar pulse B is transmitted. The master timer associates the target echo of pulse A with radar pulse B, and calculates a target range of 10 nm. This ambiguous and false range is displayed to the operator. Modern radars are designed with second time around echo as important functional modes, and engineers have developed ways to resolve the ambiguity.
A critical aspect of range determination is range resolution. Range resolution is the ability of radar to separate two targets that are close together in range and are at approximately the same azimuth. The range resolution capability is determined by pulse width. Pulse width is the time that the radar is transmitting RF energy. Pulse width is measured in microseconds.
A radar pulse in free space occupies a physical distance equal to the pulse width multiplied by the speed of light, which is about 984 feet per microsecond. If two targets are closer together than one-half of this physical distance, the radar cannot resolve the returns in range, and only one target will be displayed.
The range resolution of the radar is usually expressed in feet and can be computed using Equation
Range Resolution = (pulse width *984 ft)/2
It is the minimum separation required between two targets in order for the radar to display them separately on the radar scope.
The beamwidth of a radar system is the horizontal and vertical thickness of the radar beam. Beamwidth depends on antenna design and is normally measured in degrees from the center of the beam to the point at which the power drops off by half. This half-power point is -3 dB in power drop-off. Beamwidth governs the azimuth and elevation accuracy and resolution capability of a radar system in the same way that pulse width governs radar range accuracy and resolution.
In order for a radar system to figure out target azimuth, the antenna must be aligned with a point of reference and pointed at the target during the transmission and reception of several pulses of radar energy. If the antenna is referenced to true North, the azimuth of the target can be measured relative to true North. Azimuth determination is based on the position of the antenna when the target is being illuminated.
To provide accurate azimuth determination over a large area, many types of radar employ a narrow beam and scan the antenna in a predictable pattern. The most common scan pattern is a 360° circular scan at a constant rate. The plan position indicator (PPI) radar scope display is normally associated with this scan pattern. As the radar beam sweeps, a target is detected and displayed. The position of the antenna, when the target is displayed, shows the relative azimuth.
The azimuth accuracy of a radar system is determined by the horizontal beamwidth (HBW). Consider the following Figure, radar system A has a horizontal beamwidth of 10°. As the beam sweeps, the target is illuminated for as long as it is in the beam. This means that the target covers 10° in azimuth on the PPI scope. Radar system B has a beamwidth of 1°. A target displayed on the PPI scope will cover 1° in azimuth. The narrower the horizontal beamwidth, the better the azimuth accuracy.
Azimuth resolution is the ability of radar to display two targets flying at approximately the same range with little angular separation, such as two fighters flying line-abreast tactical formation. The azimuth resolution capability is usually expressed in nautical miles and corresponds to the minimum azimuth separation required between two targets for separate display. Azimuth resolution depends on the horizontal beamwidth of the radar. The radar system in Figure has a horizontal beamwidth of 10°. The two targets are so cIose in azimuth that the return echoes are blended into one return.
The radar system in the next Figure has a horizontal beamwidth of 1°. The radar beam not only hits the targets, but passes between them without causing a return. This allows the radars to display two distinct radar returns. A small
horizontal beamwidth improves azimuth resolution.
Azimuth resolution, in nautical miles, can be computed using Equation
Azimuth resolution = (Horizontal Beam width * Range) 60
Notice that this equation is the “60 to 1 rule” used for navigation. A 1°beamwidth will yield a one-mile-wide cell at 60 nautical miles.
Since a radar beam is three-dimensional, the vertical beamwidth is the primary factor in determining altitude resolution capability. Altitude resolution is the ability of radar to display two targets flying at approximately the same range and azimuth with little altitude separation, such as two fighters flying a vertical stack formation. The altitude resolution capability is usually expressed in feet and corresponds to the minimum altitude separation required between two targets for separate display. The radar system in Figure has a vertical beamwidth of 10°.
The two targets are so close in altitude that the return echoes depicted on the range height indicator (RHI) are blended into one.
The radar system depicted in Figure has a vertical beamwidth of 1°.This small beam not only hits the targets, but passes between them without causing a return. This allows the radar to display two distinct targets.
Altitude/elevation resolution, in thousands of feet, can be computed using
Altitude Resolution = (Vertical beam width * Range)/ 60
Radar resolution cell
A radar's pulse width, horizontal beamwidth, and vertical beamwidth form a three dimensional resolution cell (RC) . A resolution cell is the smallest volume of airspace in which a radar cannot determine the presence of more than one target. The resolution cell of a radar is a measure of how well the radar can resolve targets in range, azimuth, and altitude. The horizontal and vertical dimensions of a resolution cell vary with range. The closer to the radar, the smaller the resolution cell.
The physical dimensions of a radar's resolution cell can be computed. For a radar with a pulse width of 1 microsecond, a horizontal beamwidth of 1°, and a vertical beamwidth of 10°, the formulas for range resolution, azimuth resolution, and altitude resolution can be used to compute the dimensions of the resolution cell.
For example , at a target range of 10 nm, the physical dimensions of the radar's resolution cell are 492 feet in range, by 1000 feet in azimuth, and 10,000 feet in altitude. These figures can be confirmed by using above Equations. Based on these computations, two, or more, aircraft flying a trail formation closer than 492 feet would be displayed as a single target. Two, or more, aircraft flying line abreast closer than 1000 feet would be displayed as a single target. Two, or more, aircraft flying a vertical stack closer than 10,000 feet would be displayed as a single target. This also shows that the shorter the pulse width, the better the range resolution capability of a radar system. The narrower the horizontal beamwidth, the better the azimuth resolution capability. The narrower the vertical beamwidth, the better the altitude resolution capability.
Another type of resolution is velocity resolution. For a Doppler radar aircraft flying within the conventional resolution cell described above can be distinguished as separate targets if they have enough speed differentials.
Pulse Doppler Velocity Determination
To fully understand how a pulse Doppler radar determines target velocity, it is necessary to know more about the pulsed waveform. To generate a pulse modulated wave, a continuous carrier sine wave, like the output from a CW radar, is combined with a rectangular wave, like that of a pulse radar, to produce the pulse modulated waveform.
Mathematically, any waveform other than a sine wave is composed of many different pure sine waves added in the proper amplitude and phase relationships. In a pulsed modulated waveform, the sine waves correspond to the fundamental frequency, which is the PRF, and the sum of all harmonics in the proper amplitude and phase. The frequency of the harmonic is the basic frequency plus or minus a multiple of the PRF.
Below Figure is a plot of the harmonic content of a pulse modulated waveform operating at a carrier frequency of 2800 megahertz (MHz) with a PRF of 1 MHz. Note the loops of frequencies on either side of the carrier frequency.
These are the additions and subtractions of all the frequencies in the rectangular pulse to the carrier frequency. The important thing to remember is that there are many frequencies present, and a pulse Doppler radar must deal with a crowded frequency spectrum. This becomes even more important when one considers the fact that every frequency present will experience a Doppler shift when it is reflected by a moving target. The individual frequencies shown are called spectral lines.
For a pulse Doppler radar to accurately measure velocity, it must compare the frequency change, or Doppler shift, between the carrier frequency and the frequency returning from the target. It is a difficult task for the radar to differentiate between the returning carrier and all the harmonic frequencies.
The radar differentiates between the returning carrier frequencies and all other harmonic frequencies by using clutter cancellers, or filters, at the known harmonic frequencies. The radar cannot process frequencies cancelled by these filters. The filters create “blind speeds” for the radar. The closer together the spectral lines, the more “blind speeds” the radar will have.
Since the position of the harmonics in relation to the carrier frequency is based on PRF, the number of blind speeds can be reduced by changing the PRF of the radar. The higher the PRF, the wider the spacing of the spectral lines and the fewer blind speeds due to selective clutter canceling. However, a high PRF increases the problem of range ambiguities. Most modern pulse Doppler radars employ a medium and high PRF mode. Medium PRF equates to fewer range ambiguities but more blind speeds. High PRF has fewer blind speeds but more range ambiguities
To separate the returning target frequency shifts from all other frequencies in the returning waveform, the pulse Doppler radar employs filters to cancel the known harmonic frequency shifts. In addition, the radar cancels out all returns with no frequency shift, which equates to canceling all returns with no movement relative to the radar. However, if the radar has too many clutter filters, this creates multiple blind speeds, and targets will be missed.
Basic Radar Equation
The basic radar equation relates the range of a radar system to the characteristics of the transmitter, receiver, antenna, and the target. The radar equation provides a means not only to figure out the maximum range of a particular radar system, but it can be used to understand the factors that affect radar operation. In this section, the simple forms of the radar equation are developed, starting with the power density of the transmitting antenna to the power received by the receiving antenna.
Power density is the power of a radio wave per unit of area normal to the direction of propagation. The power density generated by a practical antenna can be expressed
Power density from Antenna = (PT*G) / (4*pi*r2)
PT = Transmitted Power
G = Antenna Gain
R = Radius of the antenna
As the radar beam propagates through space, it arrives at a target at some range (R) from the antenna. As the radar beam travels through space, the wavefront of the beam expands to a very large cross-sectional area, especially in relation to the target dimensions. The power density of the radar beam, across this wide area, at the target, is detailed in the below Equation
Power Density at Target = (PT*G) / (4*pi*r2)
PT = Transmitted Power
G = Antenna Gain
R = Range to the Target
Since the cross-sectional area of the radar beam is so large, only a small portion of the total power in the beam can be reflected toward the antenna. The rest of the radar energy continues through space and is dissipated, absorbed, or reflected by other targets. The small portion of the radar beam that hits the target is reradiated in various directions. The measure of the amount of incident power intercepted by the target and reradiated back in the direction of the antenna depends on the radar cross section (RCS) of the target. Equation details the power density of the target echo signal reflected back to the radar antenna is below
Power Density at Antenna = [(PT*G) / (4*pi*r2)] * [RCS / (4*pi*r2)]
PT = Transmitted Power
G = Antenna Gain
R = Range to the Target
RCS= Radar Cross Section
As the target echo reaches the antenna, part of the echo is captured by the antenna based on the effective aperture (Ae). Equation details the actual signal power received by the radar system follows. This is one form of the basic radar equation and is the signal strength of a radar return from a specific target at range (R) from the radar.
Signal Power Density(S) = [(PT*G*RCS*Ae) / ((4*pi) 2*r4)]
PT = Transmitted Power
G = Antenna Gain
R = Range to the Target
RCS= Radar Cross Section
Ae = Effective aperture
A detailed analysis of this equation is not required to draw some basic conclusions about the factors affecting the detection of an aircraft. If any factor in the numerator, such as transmitted power, is increased by a factor of three, the signal received by the radar will increase by only 30 percent. This clearly shows why radar system operation is characterized by the transmission of megawatts of power and the reception of microwatts of returning power. In addition, this equation shows that the most critical factor in determining radar detection is target range.
The maximum radar range (RMAX) occurs when the signal power density received just equals the minimum detectable signal (SMIN) for the receiver. Solving Equation for range, and substituting SMIN, yields the basic radar equation for RMAX for a specific target. This is another form of the basic radar equation.
R max = [(PT*G*RCS*Ae) ¼] / ((4*pi) 2* S min)]
PT = Transmitted Power
G = Antenna Gain
R = Range to the Target
RCS= Radar Cross Section
Ae = Effective aperture
Every warhead must have a fuze. Fuzes are the devices which sense the right moment to detonate the warhead. There are numerous kinds of fuzes which operate on different principles and are suitable for different kinds of missiles, warhead and environment of operation. The most common types of fuzes are impact fuze, altitude fuze, and proximity fuze.
Impact fuzes are used in all anti-tank missiles. Some anti-aircraft and anti-ship missiles also are provided with this fuze in addition to proximity fuze. In impact fuze, an electric pulse develops when it hits another solid object with a certain relative velocity which leads to high deceleration or inertia force. This electric pulse is used to trigger the warhead. The values of impact energy required for this purpose are always much above any impact that the missiles may be subjected to during normal handling and transportation operations.
In this type the warhead detonation is initiated on sensing a preset altitude. This altitude sensing could be based on barometric pressure measurement or radio-altimeter reading.
These are most often used when the impact possibility is less due to unavoidable errors in guidance and control, the missile is expected to pass in proximity if the target above or below, left or right within a certain distance. The proximity fuze can be active or passive system. In the active fuze a very low power and low range radar system transmits radiation only when the target is a small distance away and then when it receives certain strength of reflected signal it detonates. It can also be an active laser radar system. In a passive system it is generally infrared based proximity fuze.
Launchers and Ground Support Systems
All the missiles need certain ground systems to help launch them at the specific targets. Launchers are the most important of these systems. The large ballistic missiles are launched from silos under the ground or submarines or moblile vehicle based launchers. The small missiles are launched from a launch-cum-container tube resting on a human shoulder. The launchers can be very demanding piece of engineering effort with precision in aiming the launcher at a particular target and very high rates of turning in elevation and azimuth in case of' antiaircraft missiles.
In addition, the ground support requires target search and tracking facilities which are normally provided by radar or optical sights, television or infrared detectors. If the missile range is say 50 km, the search radar will have range capabilities of as much as 100 km in good weather to give adequate time for launching the missile and intercepting the target at full range of missile. The ground system is developed to withstand the environment.
For certain surface-to-air homing missiles the ground system will also help illuminate the target for the missile to home-in while command generation and transmission system is needed in command guided missiles.
In addition to these we need communication and intelligence systems also on the ground to coordinate the functions of various missile launching units and have adequate information on targets. We also need to identify between enemy aircraft and friendly aircraft before launching a missile. This system is called IFF (Identification Friend or Foe). In this audio signal at known frequencies is beamed at the suspected target and if the signal is returned by the aircraft (it is automatic without pilot's participation) then it is friendly. In the case of long distance missiles extensive support in the form of ground computers and power supplies and air-conditioning, etc., are needed.
Check out and Simulators
To certify the missiles worthy of deployment and ready for operation, a periodic health monitoring of
its vital subsystems is carried out. This is generally done through an automatic and computerized check procedure on the ground. Similarly, simulators are provided specifically for training the personnel in the operation of the missile. These simulate all the functions of the missile's electrical and microwave components.
Extensive testing of missiles proceeds with their deployment. This testing is in two phases, i.e. development testing and user evaluation testing. These tests are done at test ranges which are suitably located keeping in view the safety requirements. The ranges have instrumentation facilities to collect data for evaluation of the missile flight. The safety zones of these regions a.re very much dependent upon the size and range of the missile and the flight path. Some of the ranges are located close to the sea while some others are located in the desert areas. In India the major range facility is located in Orissa at Balasore. There are two other test ranges equipped with instrumentation for testing launch vehicles, Thumba near Trivandrum and Sriharikota. These ranges are mainly for the use of Space Department. The instrumentation facilities provide for tracking radars, electro-optic instruments and telemetry receiving stations and meteorological facilities. In the range, flight tests are carried out from the Block House. Real-time data processing facilities and other facilities exist to ensure the range safety for carrying oat flight vehicles in case of using telemetry command system.
This is the last article of our article series - Missile Technology
Thanks for reading ................
10) Mountain strike corps (XVII Corps)
XVII Corps of Indian army is the first mountain strike corps of India which has been built as an quick reaction force and as well as counter offensive force against China along LAC . Its headquarters are located at Panagarh in West Bengal.
India needs at least two Strike Corps to take the war into Chinese territory - one each for Ladakh and Arunachal Pradesh. On July 17, 2013, the Cabinet Committee on Security (CCS) approved the Army’s proposal for raising a Strike Corps for the mountains. Though the approval came after considerable delay, it was a pragmatic move that would send an appropriate message across the Himalayas.
It will help India to upgrade its military strategy against China from dissuasion to meaningful deterrence as the Strike Corps, in conjunction with the Indian Air Force (IAF), will provide the capability to launch offensive operations across the Himalayas so as to take the next war into Chinese territory, while simultaneously defending Indian territory against Chinese aggression. It would break through Chinese defences, cross over into the Tibetan plateau and capture territory that would be a bargaining chip in a post-conflict settlement. Mountain Strike Corps will have strength of around 90,000 soldiers. The army was told to complete the raising of the mountain strike corps by financial year 2017-18.
India achieved significant advancements in the direction of developing a two-layered Ballistic Missile Defence system. This enhances India's capability of dealing with a nuclear attack threat. Introduced in light of the ballistic missile threat from mainly Pakistan, it is a double-tiered system consisting of two land and sea-based interceptor missiles, namely the Prithvi Air Defence (PAD) missile for high altitude interception, and the Advanced Air Defence (AAD) Missile for lower altitude interception. The two-tiered shield should be able to intercept any incoming missile launched from 5,000 kilometres away. The system also includes an overlapping network of early warning and tracking radars, as well as command and control posts.
Development of the anti-ballistic missile system began in 1999. Around 40 public and private companies were involved in the development of the systems. Defence Research and Development Laboratory (DRDL) developed the mission control software for the AAD missile. Research Centre, Imarat (RCI) developed navigation, electromechanical actuation systems and the active radar seeker. Advanced System Laboratory (ASL) provided the motors, jet vanes and structures for the AAD and PAD. High Energy Materials Research Laboratory (HEMRL) supplied the propellants for the missile.
Two new anti ballistic missiles that can intercept IRBMs are being developed as part of Phase 2. These high speed missiles (AD-1 and AD-2) are being developed to intercept ballistic missiles with a range of around 5,000 km. The test trials of these two systems are expected to take place in 2011. The new missile will be similar to the Terminal High Altitude Area Defense missile deployed by the US. These missiles will travel at hypersonic speeds and will require radars with scan capability of over 1,500 km (930 mi) to successfully intercept the target. India is also planning to develop a laser based weapon system as part of its defence to intercept and destroy missiles soon after they are launched towards the country. DRDO's Air Defence Programme Director V K Saraswat says its ideal to destroy a ballistic missile carrying nuclear or conventional warheads in its boost phase. Saraswat further added that it will take another 10–15 years for the premier defence research institute to make it usable on the ground.
Defence Research and Development Organisation (DRDO) is working on India's future main battle tank (FMBT) with a 1,500-horsepower (HP) indigenous engine. This tank will replace beyond 2020 the imported T-72 tanks, renamed Ajeya, with the Army. Various specifications for the FMBT have been finalised. The country's military, which has projected a need for about 1,200 FMBTs. For engine development, formed a national team comprising members from the academia, the user, industry and the DRDO.
The FMBT will weigh only 50 tonnes compared to Arjun-Mark II's 62 tonnes. The DRDO is simultaneously working on Arjun-Mark II. The volume occupied by the electronics package in the FMBT will be less. The FMBT's engine will be two-thirds the size of Arjun-Mark I's, but will generate 1,500 HP compared to Arjun-Mark I's 1,400 HP. Improvements in material, fuel injection and filtration technologies will contribute to the reduction in the engine size without compromising on power.
Combat Vehicles Research and Development Establishment (CVRDE) are in the process of developing the FMBT with latest technologies. It is working in following areas:
7) Vishakapattanam class and NGD
Visakhapatnam class (Project 15B) is a class of stealth guided missile destroyers currently being built for the Indian Navy. Based on the Kolkata-class design, the Visakhapatnam class will be an extensively improved version. Ordered in 2011, the first ship is expected to be completed in 2018. Project 15B destroyers will feature enhanced stealth characteristics as well as incorporate state of the art weaponry and sensors.
The first ship of Project—15B guided missile destroyer, christened Visakhapatnam. was launched on 20 April 2015 at a ceremony at Mazagaon Dock Limited (MDL), Mumbai. The Visakhapatnam is the first of four destroyers of the class designed by the Directorate of Naval Design in New Delhi. The stealth warship has a displacement of 7,300 tons and is 163 meters long. These ships will be propelled by four gas turbines in Combined Gas and Gas (COGAG) configuration and are capable of achieving speeds in excess of 30 knots [the warships can achieve a maximum speed of 31-32 knots] with a maximum endurance of 4000 nm. The Visakhapatnam-class vessels are designed to carry two multiple-role helicopters and are equipped with a vertical launching missile system capable of engaging shore- and sea-based targets from long range.
The P15B destroyers incorporate new design concepts for improved survivability, sea keeping, stealth and ship maneuverability. State of art rail less helo traversing system is being introduced on these ships for efficient helicopter handling onboard. By increasing the cavitation inception speed the hydrodynamic noises and vibrations have been effectively reduced at the cruising speed in each of the ships of Project 15B.
These ships can truly be classified as possessing a Network of Networks, as they are equipped with Integrated Platform Management System (IPMS), Ship Data Network (SDN), Automatic Power Management System (APMS) and Combat Management System (CMS). While control and monitoring of machinery and auxiliaries is achieved through the IPMS, power management is done using the APMS. The CMS performs threat evaluation and resource allocation based on the tactical picture compiled and ammunition available onboard. The SDN is the information highway on which data from all the sensors and weapons ride.
Stealth has been a major thrust area in P15B design. Enhanced stealth features have been achieved through shaping of hull and use of radar transparent deck fittings which make these ships difficult to detect. The ship embodies features such as Multiple Fire Zones, Total Atmospheric Control System (TACS) for Air Conditioning, Battle Damage Control Systems (BDCS), Distributional Power Systems and Emergency DA to enhance survivability and reliability in emergent scenarios.
These ships are also packed with an array of state of the art weapons and sensors, including vertically launched missile system for long distance engagement of shore and sea-based targets. The ship is one of the few warships of the world to be fitted with a Multi Function Surveillance Threat Alert Radar to provide target data to Long Range Surface to Air Missile system. The MF-STAR and LRSAM system is being supplied by M/s BEL. To protect against incoming airborne and surface threats at medium and close range, the ship has 76mm and 30mm gun mounts.
Indian Navy are now planning and conceptualising next generation destroyers which would be new in design and more potent. Next-generation destroyers will have additional features than the Project 15, Project 15 A and Project 15 B. NDG will be of 13000-tonne displacement warship with conventional propulsion and will feature next-generation weapons including laser weapons.
6) HSTDV & Brahmos2
HSTDV is an unmanned scramjet demonstration aircraft for hypersonic speed flight. The HSTDV program is run by the Indian Defence Research and Development Organisation. The Defense Research and Development Laboratory’s Hypersonic Technology Demonstrator Vehicle (HSTDV) is intended to attain autonomous scramjet flight for 20 sec., using a solid rocket launch booster. The research will also inform India’s interest in reusable launch vehicles. The eventual target is to reach Mach 6.5 at an altitude of 32.5 km. (20 mi.).
India’s Defence Research and Development Organisation developed Hyper-sonic Technology Demonstrator Vehicle (HSTDV) unmanned scram-jet demonstration aircraft for hypersonic speed flight is all set for developmental flight by end of this year. Integration of all final flight hardware is happening right now and the team and is confident to conduct first hydrocarbon flight with scram-jet combustor by late this year thus joining an Elite group of countries in the world who have initiated their own scramjet engine research for hypersonic flight above Mach 5.
HSTDV Cruise vehicle will be mounted on a solid rocket motor which is covered by fairings will take it to the required altitude and once required altitude and Mach numbers are achieved cruise vehicles will be ejected out of the launch vehicle and later Scramjet engine will be auto-ignited mid-air thus taking over to propel cruise vehicle for next 20 seconds at Mach 6. The aim of planned flight test of the project is to demonstrate autonomous flight of Hypersonic scramjet integrated vehicle using hydrocarbon fuel and also measure aerodynamics of the air vehicle, its thermal properties and scramjet engine performance. HSTDV will have a flight duration of 20 seconds at an altitude of 31 km which is also cruising altitude of Boeing 747 but at Mach 6. Scramjet combustor under development is of 520kg thrust engine which has cleared 4 static test for the 20-second duration at ground test facilities at simulated speed entry condition of Mach 2.25. Performance evaluation testing of scramjet combustor was carried out on the last leg off ground-based trials last year in June which was declared successful and scramjet combustor engine was cleared for the first flight.
A supersonic missile is bad enough. But a hypersonic missile with a scramjet engine (where the through passing air is combusted at supersonic speeds unlike in ramjet engines where the air is slowed down to subsonic speeds before combustion) at Mach 20 plus is so indefensible you might as well give up the ghost. And its has tremendous range extension utility. For instance an Agni-5 with a hypersonic last stage will extend its range well beyond intercontinental distances. The Indian HSTDV-2 with a platypus nose, a titanium underside and aluminum-niodium topside, could be a strategic killer.
Probably India be only the 3rd country which posses such an advanced weapon. There are rumors that India is backing of from the project because of pressure from certain Western quarters rattled by the prospect of India’s acquiring such a potent weapon. A test of the Hypersonic Technology Demonstrator Vehicle — HSTDV-2, scheduled at TsAGI (Central Thermal Hydrodynamics Institute) in the Moscow metropolitan region in December 2014 was abruptly cancelled. The rumour is Finance Ministry did not sanction the few crore rupees worth of funds required for trans-shipping the item, testing it in Moscow.
Brahmos 2 is a hypersonic cruise missilecurrently under joint development by Russia's NPO Mashinostroeyenia and India's Defence Research and Development Organisation, which have together formed BrahMos Aerospace Private Limited. It is the second of the BrahMos series of cruise missiles. The BrahMos-II is expected to have a range of 290 kilometres and a speed of Mach 7.There is possibilities of extending the range because India joined MTCR recently.
During the cruise stage of flight the missile will be propelled by a scramjet airbreathing jet engine. Other details, including production cost and physical dimensions of the missile, are yet to be published. It is expected to be ready for testing by 2020. Expert’s belives Brahmos 2 will be based on Russian Zicron Hypersonic Maneuvering Cruise missile. Russia is developing a special and secret fuel formula to enable the BrahMos-II to exceed Mach 5.
5) Agni 6
Agni-VI is an intercontinental ballistic missile being developed by the DRDO for the use of the Indian Armed Forces Strategic Forces Command. Agni-6 ICBM visualises a range of 6,000-7,500 km; a larger payload capability than the Agni-5 to carry multiple independently targetable re-entry vehicles (MIRVs); and even manoeuvrable re-entry vehicles (MARVs) to increase survivability against enemy anti-ballistic missile systems.
The SLBM version of missile will arm the Arihant class submarines of the Indian Navy. DRDO revealed in 2012 that it is also in the process of developing another variant of Agni-VI missile. This will be a submarine-launched solid-fuel missile with a maximum range of 6,000 kilometres and a payload of three tonne
4) INS Vishal
INS Vishal (IAC-II) is the follow-on class of Vikrant aircraft carrier currently in its design phase, which will be built by Cochin Shipyard Limited for the Indian Navy. It is intended to be the first supercarrier to be built in India. The proposed design of the second carrier-class will be a new design, featuring significant changes from INS Vikrant (IAC-I), including an increase in displacement. Vishal will displace 65,000 tonnes. It will be propelled by nuclear energy
Navy already has finalised specifications of the second aircraft carrier which will include nuclear propulsion. Reactor technologies will come from India’s first nuclear submarine INS Arihant. Equipping INS Vishal with nuclear propulsions seems to be to gain greater operational endurance since warship powered by nuclear reactor means energy is unlimited and it can operate for over 20 years without refuelling
The carrier will travel at 30 knots, a hair above the Vikrant, and come in at a length of 300 meters, longer than the 262 meter Vikrant. The Navy’s letter of request also outlines plans for the carrier to field between 30 and 35 fixed-wing combat aircraft and 20 rotary wing aircraft. The Navy’s letter of request states that that carrier will be the first in the Indian fleet—and first non-Western carrier—to field a catapult launched but arrest landing (CATOBAR) aircraft launch system. There is a possibility that the CATOBAR system could incorporate General Dynamics’ new electromagnetic aircraft launch system (EMALS) technology.
Vishal will have integrated electric propulsion (IEP) or integrated full electric propulsion (IFEP) has been finally zeroed in to be integrated. IEP eliminates the mechanical connection between the engines and the propulsion which in turn reduces need for clutches and even Gear Box , Advantage of IEP for Surface ships has many advantages like reduction of weight and volume, Reduction in acoustic signatures, better placement of engines in the hull and reduced manpower for its maintenance .
Indian Navy is looking to buy four carriers-based- airborne early warning and control aircraft for INS Vishal for which Northrop Grumman has provided Navy technical information on its E-2D Advanced Hawkeye which is only AEW platform which can operate from aircraft carriers.
3) Ghatak UCAV
The classified effort to build a stealthy unmanned combat air vehicle formally received sanction as a ‘Lead-in Project’ last May, with the first funds released earlier this year. A project that has direct oversight from the Prime Minister’s Office and the National Security Advisor, Ghatak (which began as the DRDO’s Autonomous Unmanned Research Aircraft – AURA) has remained steadily out of view.
Ghatak will be powered by a modified dry thrust version of the Kaveri engine (read on for more details of this modification), will sport a flying wing planform with internal weapons and will sport stealth characteristics developed wholly in-house. Let’s now get into what hasn’t ever been reported before about the Ghatak/AURA programme.
While the Aeronautical Development Agency (ADA) is overseeing the programme along with the Gas Turbine Research Establishment (GTRE), the real R&D is being frontfooted by two academic institutions: IIT Bombay and IIT Kanpur. Since 2013, low speed experiemental studies have been carried out on the Ghatak’s serpentine intake by a team at IIT Bombay. This team has been made a kind of mini ‘Skunk Works’ towards proving computational fluid dynamics on the Ghatak, with no limits on resources and access to facilities.
Two, two specialised research teams at IIT Kanpur were roped in in 2015 for wind tunnel testing of a low RCS intake (work began in mid-2016). The second was even more significant — in November 2015, a team from IIT Kanpur was brought on board to conduct and study the autonomous flight of a low RCS aircraft configuration with a ducted fan for multiple flight modes. Scientists shared the following image with Livefist, never seen before, that provides the first official schematic of the power/thrust configuration on the Ghatak.
Over the last three-four years, the Aeronautical Development Agency has been made aware by several foreign airframers, including stealth pioneer Lockheed-Martin, Dassault, Boeing, BAE Systems,and even MiG Corp that they’d be willing to assist the Ghatak programme in a possible variety of ways — either as offsets, or a commercial consultancy arrangement. Livefist can however confirm that the Narendra Modi government has decided that the stealth component of the Ghatak programme will be entirely in-house, and will be limited to academic institutions and private industry in country.
Scientists on the AURA/Ghatak programme confirm to Livefist that concept UCAV is tied in several ways to the fifth generation AMCA development , which itself could see technology infusions from a line-up of interested suitors, including Saab, Boeing and Dassault Aviation. The latter is keen to use its Rafale deal offset commitments to feed technologies into the Ghatak (and AMCA) programmes. The ‘Lead-in project’ sanction that the ADA obtained for the government was in fact a joint sanction for both programmes, given the huge number of common R&D elements, including shaping, materials, construction, intake geometry, data-links and avionics, weapons and of course the Kaveri engine. Top sources at ADA say that full project sanction for the modified Kaveri engine.
2) Arihant Class & Next Gen SSN
The Arihant class is a class of nuclear-powered ballistic missile submarines being built for the Indian Navy. They were developed under the US$2.9 billion Advanced Technology Vessel (ATV) project to design and build nuclear-powered submarines. The lead vessel of the class, INS Arihant was launched in 2009 and after extensive sea trials, was confirmed to be commissioned in August 2016.
A follow-on class of 6 SSBNs codenamed S5 is under development. INS Aridhaman is the second Arihant-class submarine. In August 2017, it was reported that she would be launched soon and would undergo outfitting. Harbor trials and sea trials are expected to last for 2 years and commissioning is expected sometime in 2019. Work on the third SSBN submarine is going on simultaneously but details are not available.
Next Gen SSN
Government cleared a project to build six new hunter killer boats (SSN) for the Navy. A joint Navy, BARC and DRDO project, the boats will be designed by Navy’s Directorate of Naval Design and be powered by a new reactor being developed by BARC. SSNs are as important as SSBNs as they can blockade important sea routes, denying the enemy access to important resources in an event of war, and shadow enemy ships. This new SSN will be similar in size to the Arihant-class but will carry advanced torpedoes and be able to move much quicker.
1) AMCA & FGFA
Advanced Medium Combat Aircraft (AMCA) is an Indian programme to develop a 5+ generation fighter aircraft. More than four thousand staff devoted to the project, according to a report in 2015. ADA had settled upon a final design involving a twin-engine, canted twin-tail configuration, with an overall profile similar to that of the American F-22 Raptor. Mock-ups of this design have already reportedly undergone wind-tunnel and radar cross-section tests.
ADA pitches the AMCA as one of the world’s top dogfight dukes, boasting “extended detection range and targeting, supersonic persistence and high speed weapon release”. Close-combat operations will be facilitated by “high angle of attack capability, low infrared signature and all round missile warning system.
Four prototypes are expected in 2019”. That may sound overly optimistic – especially in the backdrop of stealth fighter programmes in the U.S., Russia and South Korea experiencing developmental issues. However, it is also a pointer to the Indian defence establishment’s confidence in its ability to develop an entire weapons platform from scratch after the success of the Tejas Light Combat Aircraft.
According to Livefist the first 1:1 full scale model AMCA is being built in Bengaluru. Later this year, the model will undergo a series of rigorous tests at an RCS facility in Hyderabad, where the programme team will have its fest chance at seeing how the shape they’ve chosen for the jet deals with radiation. The exercise will be historic. Because it will be the first time India will be specifically testing a stealth airframe.
Fifth Generation Fighter Aircraft (FGFA) or Perspective Multi-role Fighter (PMF) is a fifth-generation fighter being developed by India and Russia. It is a derivative project of the Russian Sukhoi Su-57 being developed for the Russian Air Force.
India and Russia inked an inter-governmental pact for the FGFA project in 2007. Proposed development of FGFA based on Su-57 5th Generation fighter aircraft has been under negotiation for last 7 years and recently Indian Air Force submitted a favorable report on co-development of FGFA but it also pushed for far more Transfer of technology and deeper Indian involvement in the project.
IAF is looking for Indian built FGFA to have nearly 70-80 % of components which can be sourced from India with Russian imports limited to less than 20-30 % range. IAF reportedly is also asking for better high thrust engines which have better serviceability and also have higher Indian made components.
Apart from this there is many other ongoing as well as completed projects such as , Project 17 A, Rafale , Tejas MK2 , Pinaka MK2 ,NETRA AWACS & Next Generation AWACS , Rustom 2 , LCH, LUH, Akash SAM, Ka 226, AH 64 Apache , Chinook 47 , Nirbhay , Kalvari Class Submarines , DSAR, Midget Subs , Next Generation Missile Vessels etc etc
Reference and Info sources
A railgun is a device that uses electromagnetic force to launch high velocity projectiles, by means of a sliding armature that is accelerated along a pair of conductive rails. US is the only country which developed a working rail-gun. Countries like India, China and Russia are researching to develop their own rail-guns. Below you can read a research paper published on Defense Science Journal in 1994. Even though it was an old article the basics are pretty much same.
A rail gun using electromagnetic propulsion was developed to launch hypervelocity projectiles. A 240 kJ, low inductance capacitor bank operating at 5 k V powered the rail gun. Launchers and projectiles were designed and developed for this purpose. The currents producing the launch forces are of the order of hundreds of kA. Even very low impedances for the current through the rail gun circuit are substantial sources of energy losses. A simulation code was developed to optimize the performance of the rail gun. Control and instrumentation facilities were set up along with a computer-based data acquisition system for measurement and analysis. The capacity to launch projectiles of 3-3.5 g weight to a velocity of more than 2.00 km/s was demonstrated.
A facility was devel6ped to launch hypervelocity projectiles using electromagnetic energy. The projectiles were launched using a railgui1. The rail gun consists of two parallel rails and a conducting metalic foil placed behind the insulating projectile. When a high current flows through the rails, the foil explodes and forms a plasma armature. The force acting on the armature is given by
Force at time t = 0.50 * Inductance per unit length of launcher * (current through the launcher at time t) 2
The rail gun currents are in the region of Hundreds of kA. This Lorentz force accelerates the projectile
An electromagnetic propulsion system requires a storage device with an energy density comparable to that of chemical explosives. The most expensive and technologically difficult part of the system is the high-energy electric source. The power sources considered for electromagnetic propulsion are well researched
Capacitor Bank and Charging Unit
The capacitor bank was used as a power source owing to its availability and lower cost despite its lower energy density. A low-inductance, 240 kJ capacitor bank was set up to provide the basic power to the railgun. A high-voltage charging unit was used to charge the capacitor bank.
High Current Switches
The capacitor energy is switched into the railgun by high-power ignitrons. When the peak current is reached, additional high-power ignitrons are used to crowbar the capacitors out of the circuit to obtain a dc pulse. This minimises the stress on the capacitors, the launcher and the projectile.
Low-inductance transmission lines were made using sandwiched conducting plates to maximize the energy transfer to the load. The transmission lines are subjected to repulsive forces owing to the passage of current through them. These, forces were 'estimated to provide proper bolting and bracing to avoid deformation of the transmission lines.
LAUNCHER AND PROJECTILE
Launchers and projectiles are subjected to high plasma pressures. High magnetic fields and high temperatures. In the present railgun set-up, the plasma pressures generated varied between 100 and 150 MPa.
A simple, single pulse driven rail gun launcher was developed with a minimum of metal components in proximity to the bore to maximize the inductance of the launcher and to improve the launch efficiency. The launcher has a 12 mm square bore cross-section. The launcher was fabricated with lengths ranging from 1 to 2 m. The following launcher designs were used for the firings:
The launchers with the last two design modifications proved more reliable and durable than the launchers based on the first design.
Thermal energy transfer from the rails leads to ablation and the melting of the bore materials. Such ablation degrades the performance of the railgun by adding parasitic mass to the plasma. The bore materials should have a high melting point and superior erosion and ablation resistance. High rail conductivity necessitated the use of copper rails. Polycarbonate and fiberglass were most suitable as bore materials. Loose bore to projectile tolerances or variation in bore dimensions can result in plasma leakage. Most of the launchers showed marked deterioration after a few shots. The deterioration could be attributed to changes in the bore dimensions due to the rail insulator ablation. Substantial deposits of carbon were observed inside the bore of the gun and needed cleaning.
The projectiles are made of Perspex or polycarbonate cubes of 12 mm length. Perspex projectiles tended to shatter. Polycarbonate projectiles survived the high plasma pressures. The plasma and the solid armature were both used for carrying the high currents. Most firings were carried out using plasma armature. A plasma armature is formed when Al/Cu foil melts/explodes on the passage of high currents. The foil vaporizes by joule heating to produce plasma to drive the armature. A neoprene obturator was placed at the rear of the projectile to seal the bore against plasma leakage around the projectile. As a deviation, a solid metallic projectile acting as an armature was also used to carry the current.
DATA ACQUISITION AND SIMULATION
A computer-based data acquisition system was set up to monitor important parameters that affect the performance of the railgun. Current transformers and Rogowski coils were used to measure the rail currents in the range6 of 100 to 500 kA. Magnetic probes were used to get the position-time profile of the projectile inside the bore of the gun and railgun current distribution. These probes help detect plasma leakage and formation of secondary arc. The velocity outside the bore of the gun was measured using shorting screens. A high-speed camera was set up to measure the velocity of the projectile and establish the integrity of the projectile at the muzzle end. This is a non-contact method and is free from electromagnetic pickups.
A simulation code was developed to predict the performance of the railgun. The performance of the model was evaluated by monitoring different parameters
All measurements were supported by appropriate software developed to analyse the entire performance of the railgun. The current-time data are used to predict the displacement, velocity and acceleration of the projectile and the plasma pressure.
Some typical railgun trial results are given in Table. Projectile velocities greater than 2000 m/s were obtained for trial no’s 1 to 3. The efficiency varied between 4 to 5 per cent with railgun current in excess of 260 kA. Plasma leakage and formation of secondary arcs were responsible for the lower projectile velocities than expected from the computer model for trial no’s 5 to 7. Trial no.7 was done using a solid conducting projectile made of aluminium. An armature was kept behind the projectile with no ablator. The armature vaporized and the plasma escaped ahead of the projectile. This led to a lower system efficiency and projectile velocity. A solid projectile made of Perspex and armatures made of several copper foils were used in trial no.4. The mass of each foil was kept around 100 mg to avoid the melting of the armature owing to the high railgun current.
Our study has shown that projectiles attain hypervelocity’s by using a single small square bore railgun. In the existing railgun facility the efficiency varied between 4 to 5 per cent. Significant improvement in the efficiency of the railgun set-up is one of the key issues that will determine the use of railguns for various weapon applications. Hence we carried out detailed modelling and simulation of the entire railgun system. The results from the simulation were validated with the measurements. Measurements made at high common mode voltages of around 1000s of volts and high electromagnetic noise were exceptionally good, providing reliable and repeatable records. Intact projectile launch and 2-3 m of free flight projectile were studied using high-speed photography when punctures in the shorting screens were observed. Using a high-speed camera the integrity of the projectile was established beyond doubt. A 12 mm cubical polycarbonate projectile weighing about 3 g could defeat a 6 mm aluminium sheet at 2 m from the muzzle end of the gun). The complete railgun system was also placed in a 5 m long vacuum chamber to study the railgun performance. Our studies are as yet inconclusive. Owing to the failure of some odd capacitors in the capacitor bank, repetitive trials could not be carried using the full energy of the bank. The energy extracted from the capacitor bank varied between 120 and 160 kJ. The kinetic energy of the projectiles can be increased substantially by using a higher-energy capacitor bank as a power source
Due to unknown reasons Rail-gun development was not completed at that time. But from this press release of Ministry of Defense, it is clear that DRDO restarted their work in the field of Electromagnetic rail gun along with other futuristic technologies like Supersonic Missile Assisted Release of Torpedo, Stealth Wing Flying Test bed, AESA Based Integrated Sensor Suite, Multi-Agent Robotics System etc
Defense Science Journal, Val 44, No 3, July 1994, pp 257-262
S.G. Tatake, K.J. Daniel, K.R. Rao, A.A. Ghosh, and I.I. Khan
Armament research & Development Establishment Pune-410121
There are five main things a pilot must remain aware of when contemplating aerial engagement, of which, getting sight of your opponent and keeping sight of them are the most important. Other major factors influence a dog fights are, thrust-to-weight ratio, wing loading, and the "corner speed" (the maximum/minimum speed at which the aircraft can attain the best turning performance). Apart from this, variable limitations must also be considered, such as turn radius, turn rate, and the specific energy of the aircraft. The concept of energy awareness during air combat is not new. Wise use and conservation of energy during combat will increase your chances of victory.
Missiles are generally made from aluminium and its alloys, steel, magnesium and titanium. The major concern is the strength-to-weight ratio of the material. Higher this ratio the better. On account of the high temperatures encountered by missiles flying at supersonic speeds and needs for lighter materials, newer materials are coming into usage. Fibre-reinforced plastics (FRP) like the carbon-carbon variety, graphite compounds, molybdenum, beryllium, etc.
Some of the important factors calling for adequate caution during material selection are as follows:
The individual components of a radar determine the capabilities and limitations of a particular radar system. The characteristics of these components also determine the countermeasures that will be effective against a specific radar system. Here we will discuss the components of basic pulse radar, continuous wave (CW) radar, a pulse Doppler radar, and monopulse radar.
PULSE RADAR SYSTEM
The most common type of radar design is the pulse radar system. The name describes a process of transmitting discrete bursts of RF energy at the frequency of the radar system. The time that pulses are transmitted determines the pulse repetition frequency (PRF) of the radar system. A pulse radar system can figure out range and azimuth. Range is determined by the time that it takes a pulse to go to a target and return. Target azimuth is determined by the relative position, or antenna orientation, when the pulse strikes the target.
A major important item in the aerodynamic missile configuration is the wing or the main lifting surface. A great variety of wing planforms or configurations are used. Without going into the detailed analyses for optimisation of the configuration, only the names of a few well-known theories are stated here.
The linearised theory is used in supersoninc flow over wings. This theory is derived from the exact differential equation of steady compressible flow. There are also a few equations of first order and linear equations called 'Ackeret Theory'. The basic assumptions made are: (a) the airfoil is thin, and (b) the flow is two dimensional, to mention a few typical ideal assumptions which one comes across many a time.
A few higher order terms have been derived making use of constants called the 'Busemann constants' owing their name to the man who derived them. This derivation makes use of expansion series which are mainly mathematical.
A straight wing planform is the one which is often used. Two other basic wing planforms used are delta and swept back wings. There are many variations of these basic planforms. Due to the advantages and disadvantages associated with each of the basic planforms used, a thorough study involving their aerodynamic efficiency, structrual weight and cost of manufacturing is often called for.
In the analysis of wings of arbitrary planform it is important to know whether the leading (and trailing) edge is subsonic or supersonic since the pressure distribution is markedly different for each condition. Extensive experimental investigations have been conducted to determine and compare the aerodynamic characteristics (commonly called as chics') of the basic planforms for practical applications. The factors taken into account are Reynold's number, fluid viscosity and such other dimensional properties. Thus, airfoil is the cross section of a wing which gives a minimum drag and a maximum lift.
The pressure over an airfoil is primarily a function of the angle between the free stream air direction and the surface. The airfoil shape or section for supersonic application is noticeably different from those sections used in the subsonic region. In general, sharp nosed symmetrical airfoil sections of the double wedge, modified double-wedge, or biconvex variety result in the most efficient aerodynamic design.
Every radar produces a radio frequency (RF) signal with specific characteristics that differentiate it from all other signals and define its capabilities and limitations. Pulse width (pulse duration), pulse recurrence time (pulse repetition interval), pulse repetition frequency, and power are all radar signal characteristics determined by the radar transmitter. Listening time, rest time, and recovery time are radar receiver characteristics. An understanding of the terms used to describe these characteristics is critical to understanding radar operation.
PULSE WIDTH (PW)
PW, sometimes called pulse duration (PD), is the time that the transmitter is sending out RF energy. PW is measured in microseconds. It has an impact on range resolution capability, that is, how accurately the radar can discriminate between two targets based on range.
The pulse width of the transmitted signal is to ensure that the radar emits sufficient energy to allow that the reflected pulse is detectable by its receiver. The amount of energy that can be delivered to a distant target is the product of two things; the output power of the transmitter, and the duration of the transmission. Therefore, pulse width constrains the maximum detection range of a target.
Weapons-control radar, which requires great precision, should be able to distinguish between targets that are only yards apart. Search radar is usually less precise and only distinguishes between targets that are hundreds of yards or even miles apart. Resolution is usually divided into two categories; range resolution and bearing resolution.
Range resolution is the ability of a radar system to distinguish between two or more targets on the same bearing but at different ranges. The degree of range resolution depends on the width of the transmitted pulse, the types and sizes of targets, and the efficiency of the receiver and indicator. Pulse width is the primary factor in range resolution. A well-designed radar system, with all other factors at maximum efficiency, should be able to distinguish targets separated by one-half the pulse width time.
PULSE RECURRENCE TIME (PRT)
Pulse recurrence time is also known as pulse repetition time. PRT is the time required for a complete transmission cycle. This is the time from the beginning of one pulse of RF energy to the beginning of the next. PRT is measured in microseconds. PRT is the same as pulse repetition interval (PRI), which is used in radar warning receivers and other electronic warfare support (ES) assets to discriminate between radar systems. It also affects maximum radar range.
ELECTRONIC warfare (EW) is the systems approach to the exploitation and control, to the maximum extent possible, of the electromagnetic (EM) spectrum. It is an important capability that can advance desired military, diplomatic, and economic objectives or, conversely, impede undesired ones. The use by an adversary of the EM spectrum for communications, navigation, and radar functions can be challenged by the techniques and technology of EW systems. In a military application, EW provides the means to counter, in all battle phases, hostile actions that involve the EM spectrum—from the beginning when enemy forces are mobilized for an attack, through to the final engagement. EW exploits the EM environment by sensing and analyzing an adversary’s application of the spectrum and imposing appropriate countermeasures (CMs) to hostile spectrum use.
CHARACTERISTICS OF RF RADIATION
In order for a radar system to determine range, azimuth, elevation, or velocity data, it must transmit and receive electromagnetic radiation. This electromagnetic radiation is referred to as radio frequency (RF) radiation. RF transmissions have specific characteristics that determine the capabilities and limitations of a radar system to provide these target discriminants, based on an analysis of the characteristics of the target return. The frequency of transmitted RF energy affects the ability of a radar system to analyze target return, based on time, to determine target range. RF frequency also affects the ability of the transmitting antenna to focus RF energy into a narrow beam to provide azimuth and elevation information. The wavelength and frequency of the transmitted RF energy impact the propagation of the radar signal through the atmosphere. The polarization of the RF signal affects the amount of clutter the radar must contend with. The ability of a radar system to use the Doppler effect in analyzing the radar return impacts the velocity discrimination capability of the radar.
The output signal from a typical radar system has several important characteristics that affect the capabilities and limitations of radar systems. The first characteristic considered is usually RF. The frequency of the transmitted signal is the number of times per second the RF energy completes one cycle. The basic unit of measurement is the hertz (Hz). One hertz equals one cycle per second. Most radar has an RF in the millions of hertz.
While official Chinese media have been quite reactive and open with the launched of the People's Liberation Army Navy (PLAN or Chinese Navy) first Type 055 Destroyer (they did publish official images of the ceremony just two hours after it took place), details on the specifications of the ship, especially its sensor suite, are still scarce. But with plenty of imagery of Type 055 sensors now available, Navy Recognition contacted two retired French Navy officers (a former frigate commander and a former electronic warfare specialist) in order to try and learn more about the PLAN's latest surface combatant's sensors.
Upmast of Type 055 during its launch (left) and upmast of the shore integration facility at Wuhan's 701 institute (right)
This analysis based on open source intelligence (and mainly images) is limited because of the limited sources of images. All information here are hypotheses or "guesses" to the best of our sources' knowledge.
Our experts first underline that the sensor fit aboard the vessel is not complete yet. In the image above, you may notice that what is likely a TACAN (tactical air navigation system ) antenna fitted on top of the mast at the shore integration facility (right) is not present on the destroyer's actual mast (left). Some elements above the pilot house / bridge appear to be reinforced and are likely future placements for various sensors including an electro-optic s fire control system for the main gun. Navigation radar appear to be missing too. Note also that the 055 mast appear to be fitted with some kind of RCS reduction shields compared to the bare mast on the right.
Study of the movement of a body in the presence of air is called aerodynamics and this study is vitally important for the design of aircraft, missiles and rockets. The atmosphere as we know is densest close to earth's surface at sea level. As we go higher it becomes thinner (i.e.? the pressure and density are lower). The sensible atmosphere is upto a height of about 80 kilometers. The temperature also varies with height. The layer of atmosphere nearest to earth is called troposphere. Above that is stratosphere which is further subdivided into lower stratosphere and upper stratosphere. Beyond that, is ionosphere or ozonosphere and the last is exosphere. The very high speed fighter aircraft fly upto altitudes of about 30 km, while transport jets fly upto about 10-11 km.
The aircraft and missiles are bodies that are heavier than air and so can support their weights only if they produce a force to counter it. This force can be either lift force generated by the flow of air over the wings and body or generated by means of an engine in the form of thrust. This is done by helicopters or by aircraft with swing-engines (vertical takeoff type) where main engines can be swiveled. In missiles (most are launched vertically or with an inclination), a part of the weight is countered by the rocket engine thrust.
When we have a body with wings or without wings moving through air, there are forces generated which act on the body to oppose its motion (drag). In other words, this force must also be countered by the engine's thrust. .The drag force depends upon the fineness or bluntness and size of the body. To minimize the drag force one has to choose the aerodynamic shape such that functional requirements are also met.
In the missiles aerodynamic surfaces called wings, fins, and control surfaces and body called fuselage (with suitable nose shape conical or ogival followed by cylindrical) are designed to provide the necessary lateral maneouvrabilitv. This is achieved by deflecting control surfaces through actuation mechanism and thereby altering the balance of forces and generating turning moments. This happens at a very rapid rate.
In cruise missiles wings are provided to generate lift force while the missile flies in horizontal level mode. Most of the aerodynamics is studied by mathematical analysis of flow and then further validated by tests on scaled-down models in wind tunnel where forces are measured and correlations generated. An experimental data bank is generated for subsequent designers.
Aerodynamic considerations and structural design factors are intimately related to the propulsion and guidance aspects. The external missile shape and design is finalized keeping in view the needs of other subsystems and performance criteria. Thus mechanical and electric missile system engineers take equally important part in the overall missile design. This calls for a need to have a good insight and appreciation on the part of these personnel for the overall missile design.
Aerodynamic characteristics of various external components and their configuration aid their selection towards an optimum missile performance with respect to its lift and drag characteristics, aerodynamic stability, maneuverability, etc. Comprehensive and accurate data to enable a missile technologist to zero-in on a particular configuration is not readily available since much of the essential data is classified. Moreover, the requirement of stupendous quality of data desirable and sufficient for a fairly efficient design is a deterring factor too. However, an important asset the missile engineer: must have in discharging any R&D assignment is a sound understanding and knowledge of the fundamental principles involved in all the subsystems. The fundamentals of many technically specialized areas-aerodynamics, thermodynamics (mainly heat transfer), kinematics, propulsion, structural design-are a necessity though it makes the task of the aeronautical design engineer rather complex. Some of the major considerations the latter should have for an optimization of design are enumerated here.
The body of the missile may be divided into three major sections the - fore body or the nose, the mid-section and the aft or boat-tail section.
This is something what a photonic radar sees, the world around it.
In a race of making fifth generation combat aircrafts nations have realised that stealth capability is a major game changer in both wartimes and peace times. The rumoured destruction of Syrian S-300 battery by Israeli F 35s and the claimed uncontested flight of American F 22 Raptor at engagement ranges of the glorious S 400 prompts the Russians ( and everyone else) to think out an effective counter to this low observability technology. They seem to have found solution in an old abandoned concept where detection happens with the help of light and not radio waves. It works in similar way as that radar but uses infrared light beams instead of radio waves. If stated capabilities are to be believed then this new system would be able to detect stealth aircrafts at long ranges. The stealth aircrafts have measures taken to reduce the reflection of X band radio waves. The Radio Optic Phased Array Radar makers claim that since it uses light and not radio waves the optimisation of reduced radio waves reflections is not going to work. In this article we have attempted to dig out weather the claim is true or just another bragging. How exactly this thing works, what are its specific capabilities and whom are working in this field. Do give your opinion at the end.
The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated by NASA, as part of the Space Shuttle program. In this article, we examine the monumental technology behind America's shuttle program, the mission it was designed to carry out.
First, let's look at the parts of the space shuttle and a typical mission.
The space shuttle consists of the following major components:
A typical shuttle mission is as follows:
To lift the 4.5 million pound (2.05 million kg) shuttle from the pad to orbit (115 to 400 miles/185 to 643 km) above the Earth, the shuttle uses the following components:
Lasers have become an indispensable part of modern day battlefield. Depending on the wavelength and power; lasers have wide spectrum of military applications from dazzling human eye to shooting down a UAV, guiding munitions for precision strike, imaging enemy targets and detecting chemical, biological and explosive materials.
Laser Science and Technology Centre (LASTEC) is working for the development of laser source technologies for Directed Energy Weapon (DEW), dazzling and imaging applications. It is developing standalone sensor systems using different laser sources for applications like detection and location of optical targets and detection and identification of chemical, biological and explosive materials. Other laser systems developed by LASTEC include unexploded ordnance disposal system and different variants of dazzlers. LASTEC is also working in the area of electro-optic countermeasure systems and development of laser materials.
Over the years, LASTEC has acquired the expertise in designing, testing and evaluation of different types of laser sources and systems. Gas Dynamic Laser and Chemical Oxygen and Iodine Laser Sources of the order of tens to hundreds of kilowatts for DEW application have been successfully developed and demonstrated. Recently, single mode kW class Fiber Laser Source was realized in collaboration with foreign experts making India only the 6th (known) country to possess the requisite technological knowhow. Efforts are channelized in scaling the power levels of these laser sources.
Scientific principles and techniques like Raman scattering and its variants, laser photo acoustics, laser induced fluorescence, differential absorption, etc. have been aptly applied to develop a number of equipment for detection and identification of various chemical, biological and explosives warfare agents in field conditions. These equipments are at various stages of evaluation and have tremendous application in low intensity conflict operations.
A number of sub-system level technologies for building the most modern state-of-the-art laser systems for military applications have also been successfully developed. Expertise in associated technologies like beam pointing and tracking, embedded system design and thermal management has been achieved. FACET, a state-of-the-art facility for test and evaluation of laser systems has been established at Ramgarh, Chandigarh.
LASTEC is committed to provide world class laser sources and systems, using state-of-the-art technologies and complying to the world standards. The systems being developed are contemporary to those developed by the world leading military laser manufacturers and are appropriate to the Indian conditions.
The indigenous laser sources, equipment and associated technologies developed by LASTEC/ sucoF ygolonhceTDRDO have been covered in two issues of Technology Focus. I hope this issue of will be useful in generating awareness about the tireless efforts of DRDO in developing cutting-edge defence technologies in the area of Laser Sources.
In missiles the control function is to ensure stability of the missile and implement the guidance signals received from external sources or generated onboard. The control, after processing the guidance signals, actuates the aerodynamic surfaces or thrust vector to generate turn of the missile speed and direction as required.
The guidance system is to detect whether the missile is flying above or below, to the left or right, of the required path. It obtains these deviations or errors and sends signals to the control system to reduce these errors to zero. The task of the control system therefore is to manoeuvre the missile quickly and efficiently making use of these signals.
In order to appreciate controls we shall briefly describe the motion of the missile as a free body. The missile has a total of six degrees of freedom of movement. Out of this, three degrees are translational or linear about the three axes viz., x, y and z; while the other degrees are rotational movement about three axes termed as pitch, yaw and roll.
Pitch is the turn of missile when it climbs up or down. Yaw is its turn to left or right. The roll is when the missile rotates about its longitudinal axis, which is also called roll axis. The longitudinal axis is the one running from nose to tail. If a missile is resting horizontally then, the pitch axis is the one which is normal to longitudinal axis and parallel to the horizontal axis and pitch axis. Missiles can roll when in motion due to various reasons.
There are missiles in which roll is controlled. Roll can be sensed onboard using a free gyro sensor and eliminated through actuation of controls. Some missiles have roll induced by design to use it for stability. The other axes which are controlled for motion are pitch and yaw axes.
Tejas is a 4+ generation, supersonic, highly maneuverable, multi-role, smallest and lightest in its class contemporary combat aircraft designed for the Indian Air Force designed and developed by DRDO. It is considered ‘game changer’ for India’s air defense preparedness.
The LCA has been designed and developed by a consortium of five aircraft research, design, production and product support organizations pooled by the Bangalore-based Aeronautical Development Agency (ADA), under Department of Defense Research and Development Organization (DRDO). Hindustan Aeronautics Limited (HAL) is the Principal Partner in the design and fabrication of the LCA and its integration leading to flight testing. Several academic institutions from over the country have participated in the development of design and manufacturing software for LCA. National teams formed by pooling the talents and expertise in the country are entrusted with the responsibility of the development of major tasks such as development of carbon composite wing, design, design of control law and flight testing. Several private and public sector organizations have also supported design and manufacture of various LCA sub-systems.
The LCA design was finalized in 1990 as a small tail-less delta winged machine with relaxed static stability (RSS) to enhance maneuverability performance and a host of other advanced features. A review committee was formed in May 1989 which reported that Indian infrastructure, facilities and technology had advanced sufficiently in most areas to undertake the project. It was decided that the full-scale engineering development (FSED) stage of the programme would proceed in two stages.
An air-breathing engine is an engine that takes in air from its surroundings in order to burn fuel. All practical air breathing engines are internal combustion engines that directly heat the air by burning fuel, with the resultant hot gases used for propulsion via a propulsive nozzle. A continuous stream of air flows through the air-breathing engine. The air is compressed, mixed with fuel, ignited and expelled as the exhaust gas. Thrust produced by a typical air-breathing engine is about eight times greater than its weight.
The thrust results from the expulsion of the working gases from the exhaust nozzle. To expel the gases from the nozzle at high velocity, the air entering the combustion chamber of the engine is compressed.
There are so many arguments and debates related to the detection of stealth fighters are happening around. Here we are presenting a simple method to find the detection range of radars against stealth fighters.
Below you can see the radar equation, various parameters that affect the range of radar and how these variables individually affect the detection range.
R max = 4th root of ((Pt * G2*lamda 2 * RCS) / ((4 Pie) 3 * P Min))
The variables in the above equation are constant and radar dependent except target RCS.
Over the last decades, air forces have always been the first military component engaged in all crises or conflicts, from the Falklands to the Gulf, from Bosnia to Kosovo, from Afghanistan to Libya, and more recently Mali, the Central African Republic and Iraq.
Military aviation is undoubtedly the most strategic weapon today, both in terms of combat effectiveness and of critical technologies implemented. In modern warfare, air dominance from day one is a must, so that air-to-ground and air-to-sea operations can be conducted safely and efficiently. The decisive place of the air component in modern warfare is demonstrated by the defense strategies decided by those nations who want to keep a leading role on the world stage. The RAFALE, with its “OMNIROLE” capabilities, is the right answer to the capability approach selected by an increasing number of governments.
It fully complies with the requirement to carry out the widest range of roles with the smallest number of aircraft. The RAFALE participates in permanent “Quick Reaction Alert” (QRA) / air-defense / air sovereignty missions, power projection and deployments for external missions, deep strike missions, air support for ground forces, reconnaissance missions, pilot training sorties and nuclear deterrence duties.
Lessons learned from the latest conflicts where air power was used, can be summarized into four overarching expectations about weapon systems by political decision makers:
The “OMNIROLE” RAFALE combines all these advantages: it is relevant against both traditional and asymmetrical threats, it addresses the emerging needs of the armed forces in a changing geopolitical context, and it remains at the forefront of technical innovation.
Thanks to its versatility, its adaptability and its ability to meet all air mission requirements, the RAFALE is the “poster child” transformational fighter which provides a way forward to air forces confronted to the requirement of doing “more” with “less”, in an ever-changing strategic and economic environment.
Of a moderate size, yet extremely powerful, superbly agile and very discrete, the latest type of combat aircraft from DASSAULT AVIATION does not only integrate the largest and most modern range of sensors, it also multiplies their efficiency with a technological breakthrough, the “multi-sensor data fusion”.
Omnirole by design
When the RAFALE programme was launched, the French Air Force and French Navy published a joint requirement for an omnirole aircraft that would have to replace the seven types of combat aircraft then in operation.
The new aircraft would have to be able to carry out a very wide range of missions:
A fully optimized airframe
The RAFALE, a fully “OMNIROLE” fighter, is available in three variants:
All three variants share a common airframe and a common mission system, the differences between naval and land versions being mainly limited to the undercarriage and to the arresting hook.
The RAFALE features a delta wing with close-coupled canards. In-house research in computational fluid dynamics has shown the specific benefits of close coupling between the wings and the canards: it ensures a wide range of centre of gravity positions for all flight conditions, as well as excellent handling throughout the whole flight envelope. The close-coupled canards / delta wing configuration is key to the combat performance of the RAFALE: even at high angle-of-attack, it remains fully agile, and its range performance in strike missions with heavy weapon loads is unmatched for such a compact design. Close-coupled delta-canard wing offers significantly higher maximum lift coefficient and positive trim lift on all control surfaces. Further, canards and wing control surfaces overlap in their functionality, unlike with horizontal tail configuration, leading to improved damage resistance. Rafale’s close-coupled canards will allow purely aerodynamic spin recovery. Also Rafale’s close coupled canards will reduce pressure point shift with increased speed, allowing Rafale to remain aerodynamically unstable at higher speeds than non-canard configuration would.
The aircrafts a close-coupled design with two large canards, four leading-edge slats, four trailing elevons and one rudder to optimize lift/drag and reduce side-slip in all flight phases. The hydraulic system powering the flying controls operates at over 345bar (5,000lb/in2).
The aircraft is capable of withstanding from −3.6g to 9g (10.5g on Rafale solo display and a maximum of 11g can be reached in case of emergency). The Digital Fly by wire Control System is a "g" demand system with +9.0g/29° angle of attack (AoA) limit in air-to-air mode and +5.5g/20° AoA limit in both of the two air-to-ground/heavy stores modes (ST1 and ST2) to cater for forward or aft centre of gravity. The aircraft continuously "recognises" the load it carries, but indicates and leaves the final DFCS mode selection to the pilot. Minus g limit in all modes is -3.2.The Rafale is an aerodynamically unstable aircraft and uses digital fly-by-wire flight controls to artificially enforce and maintain stability. The aircraft's canards also act to reduce the minimum landing speed to 115 knots (213 km/h; 132 mph); while in flight, airspeeds as low as 15 knots (28 km/h; 17 mph) have been observed during training missions. According to simulations by Dassault, the Rafale has sufficient low speed performance to operate from STOBAR-configured aircraft carriers, and can take off using a ski-jump with no modifications.
The Dassault Rafale is a relatively small, light airplane. Therefore, it isn’t surprising that its wing loading ratio (the ratio of its weight compared to its wing space) is just 306 kg/sq m, the second lowest ratio on the market after the JAS-39 Gripen. Its combat radius is also impressive – 1,852 kilometers. The Rafale also has an excellent rate of climb – 304 m/s, i.e. 60,000 ft/min. This means the plane can climb to its service ceiling (55,000 ft) in a minute. Dassault Rafale has instantaneous turn rate of 30 deg/s, sustained turn rate of 24 deg/s and roll rate of 290 deg/s.
Flight Control Systems
An advanced digital “Fly-by-Wire” (FBW) Flight Control System (FCS) provides for longitudinal stability and superior handling performance. The FCS is quadruple redundant with three digital channels and one separately designed analogue channel, with no mechanical back-up: design independence between channels is key to avoiding simultaneous anomalies on all channels.
The Flight Control System of the RAFALE attains the highest level of flight safety by leveraging on the extensive experience of DASSAULT AVIATION in Fly-by-Wire technology: over one million flight hours without a single accident caused by the FCS. The RAFALE is safe and easy to fly in all flight regimes, featuring the same precise, yet benign handling performance in all load-out configurations throughout the flight envelope.
The flight control system of the RAFALE offers auto flight in terrain following mode in all weather conditions, allowing the RAFALE to fly unobserved in the opponent’s airspace: an important survivability factor in a high threat environment.
Thanks to the DASSAULTs unique know-how in finite element modeling, the RAFALE airframe fatigue is monitored with the same gauge-free concept which has proved its worth on the MIRAGE 2000 fleet. Composite materials are extensively used in the RAFALE and they account for 70% of the wetted area. They also account for the 40% increase in the max take-off weight to empty weight ratio compared with traditional airframes built of aluminium and titanium.
The M88 – a new generation engine
The M88-2 is a new-generation turbofan engine offering a high thrust-to-weight ratio with easy maintainability, high despatch reliability and lower operating costs. The M88-2 incorporates advanced technologies such as integrally bladed compressor disks (“blisks”), a low-pollution combustor with smoke-free emissions, single-crystal high-pressure turbine blades, ceramic coatings, and composite materials.
The M88-2 power plant is rated at 10,971 lbs dry and 16,620 lbs with afterburner. It is equipped with redundant “Full Authority Digital Engine Control” (FADEC), which provides for carefree engine handling anywhere in the flight envelope: the throttle can be slammed from combat power to idle and back to combat power again, with less than three seconds from idle to full afterburner. The aircraft has a fixed flight refuelling probe and its canards and elevons operate in conjunction to act as a fully variable airbrake, with both features intended to save weight. Maximum speed is M1.8/750kt (1,390km/h), service ceiling 55,000ft (16,800m), and typical approach speed at mid-weight (15t) and 16° AoA an indicated 125kt.Powerful carbon brakes allow for landing distances as short as 450m without the need for a brake parachute.
Launched in 2008, the M88 TCO (“Total Cost of Ownership”) programme was initiated to further improve engine durability and bring support costs down. Capitalizing on the ECO project, SNECMA was able to upgrade the high-pressure compressor and the high-pressure turbine of the M88-2: cooling is ameliorated and stronger components have been introduced, boosting durability by up to 50%. Life expectancy between overhaul has been considerably expanded for a number of modules, helping further minimize the impact of planned maintenance on engine availability. The M88 is the subject of a constant improvement effort by SNECMA, leading to the latest M88-4E version, which builds on the TCO programme. This version, which offers a longer engine life, is now fully operational. Production deliveries began in 2012, and RAFALE aircraft now comes out of the production line fitted with M88-4Es.The Snecma M88 turbofans have been optimized to limit infrared delectability. And it also received Hot Spot treatment, to reduce the InfraRed Signature.
Although not a full-aspect stealth aircraft, the cost of which was viewed as unacceptably excessive, the Rafale was designed for a reduced radar cross-section (RCS) and infrared signature . In order to reduce the RCS, changes from the initial technology demonstrator include a reduction in the size of the tail-fin, fuselage reshaping, repositioning of the engine air inlets underneath the aircraft's wing, and the extensive use of composite materials and serrated patterns for the construction of the trailing edges of the wings and canards. 70% of the Rafale's surface area is composite. Many of the features designed to reduce the Rafale's visibility to threats remain classified. The radar cross section of the airframe has been kept to the lowest possible value by selecting the most adequate outer mold line and materials. Most of the stealth design features are classified, but some of them are clearly visible, such as the serrated patterns on the trailing edge of the wings and canards.
To achieve Stealth Dassault combine four factors:
• RCS reduction of the most reflective parts of the structure
• Development of passive detections
• EW suite capable of jamming and decoying
• Terrain following system
The minimal RCS of Rafale, according to Dassault engineer (1/10~1/20 of Mirage-2000's frontal RCS), should be 0.05 to 0.1 m2 class.
Rafale makes extensive use of radar-absorbent material (RAM) in the form of paints and other materials. RAM forms a saw-toothed pattern on the wing and canard trailing edges, for instance. The aircraft is designed to, so that its untreated radar signature is concentrated in a few strong "spikes," which are then suppressed by the selective use of RAM.
75% of Rafale surface structure and 30% of its mass are made of composites. Besides, the high amount of composites and RAM materials, ducted air intakes, Rafale also has a sawtooth design feature all over the airframe and even in the air intakes. These sawtooth are made of RAM materials and meant to scatter and absorb radar waves. IRST surface of rafale is covered in gold shield which reflects very less radar energy and thus has stealth. The internals of the cockpit are RCS shaped as well as the canopy containing gold and RAM coat on the mounts which reflects very less radar reflection.
Terrain following system
The Rafale is fitted with a multisensory terrain-following system operating at the pilot's choice from the radar or from a digital terrain database: the RBE2 radar can detect even unreported obstruction and the digital terrain database does away with telltale emissions where total covertness is required. There is also a radar altimeter available in nap-of-the-earth flight over water or flat land. Data fusion is part of the system to cross-check the sensors before feeding their data to a flight path computation module whose development has been carried out per the exacting standards of safety-critical engineering.
The terrain-following function integrated with the Rafale's flight control system actually flies the aircraft closer to the ground or the sea than would be reasonable for the crew flying in manual mode - and it does so with a demonstrated safety level even in blind weather. Rafale is designed to fly a terrain-avoidance/threat- avoidance profile at 5.5 g and 100 feet in altitude.
It remains a valuable help to the crew even when flying higher above ground level, allowing them to concentrate on other mission tasks without the burden -and energy consuming anxiety - of maintaining terrain clearance during hi-speed/low-altitude legs. With its high thrust and low wing-loading, the Rafale is equally at ease flying at treetop height: its aerodynamics - delta wing and canards - is ideal for low-level agility and ride quality, and its canard fore-planes do not block downward visibility. Flying low and fast in the clouds then becomes a real option: high altitude SAMs are no longer an issue since you fly under the radar coverage, and short range optically-guided air defenses are powerless against a foe they cannot see. Other short range air defense systems can be dealt with by the Spectra EW suite capable of jamming and decoying. Speed is part of the game too, since air defense engagement zones are dramatically reduced against transonic targets, even in clear weather.
The Rafale core avionics systems employ an integrated modular avionics (IMA), called MDPU (modular data processing unit). This architecture hosts all the main aircraft functions such as the flight management system, data fusion, fire control, and the man-machine interface. The total value of the radar, electronic communications and self-protection equipment is about 30 percent of the cost of the entire aircraft.
The Rafale features an integrated defensive-aids system named SPECTRA, which protects the aircraft against airborne and ground threats, developed as a joint venture between Thales and MBDA. Various methods of detection, jamming, and decoying have been incorporated, and the system has been designed to be highly re-programmable for addressing new threats and incorporating additional sub-systems in the future. Operations over Libya were greatly assisted by SPECTRA, allowing Rafales to perform missions independently from the support of dedicated Suppression of Enemy Air Defenses (SEAD) platforms.
The Rafale's ground attack capability is heavily reliant upon sensory targeting pods, such as Thales Optronics's Reco New Generation/Areos reconnaissance pod and Damocles electro-optical/laser designation pod. Together, these systems provide targeting information, enable tactical reconnaissance missions, and are integrated with the Rafale's IMA architecture to provide analysed data feeds to friendly units and ground stations, as well as to the pilot. Damocles provides targeting information to the various armaments carried by the Rafale and is directly integrated with the Rafale's VHF/UHF secure radio to communicate target information with other aircraft. It also performs other key functions such as aerial optical surveillance and is integrated with the navigation system as a FLIR.
Thales' Areos reconnaissance pod is an all-weather; night-and-day-capable reconnaissance system employed on the Rafale, and provides a significantly improved reconnaissance capability over preceding platforms. Areos has been designed to perform reconnaissance under various mission profiles and condition, using multiple day/night sensors and its own independent communications data links
RBE2-AA / AESA – “Active Electronically Scanned Array” radar
The RAFALE is the first operational – and so far, the only – European combat aircraft to use an electronic scanning radar. Developed by THALES, the RBE2 radar has benefited from a massive research effort and from THALES’ unmatched know-how based on past experience. Compared to radars with conventional antennas, unprecedented levels of situational awareness are attained with earlier detection and tracking of multiple targets. With its superior beam agility and its enormous computing power, the RBE2 offers outstanding performance that cannot be replicated by mechanical scanning radars.
In October 2012, the first RAFALE fighter equipped with an “Active Electronically Scanned Array” (AESA) RBE2 radar was delivered to the French MoD. The AESA provides a wide range of functions:
The RBE2-AESA is fully compatible in terms of detection range with the upcoming long range METEOR air-to-air missile. The AESA offers an unprecedented growth-potential for the future. In those situations where discretion becomes the single most important tactical factor, the RAFALE can rely on several other sensor systems. RBE-2 has 120* angular coverage while RBE-2AA (AESA) has 140* angular coverage.
The RBE2-AA radar system is an active electronically scanned array (AESA) radar system derived from the Rafale’s RBE2 radar. It replaces the mechanically steered array antenna by electronically steering exerted by up to several thousand of transmit-receive modules which enable maximum performance and versatility as well as enhanced reliability. The radar is using about 1000 GaAs T/R modules and is reported to deliver a greater detection range of 200 km, improved reliability and reduced maintenance demands over the preceding radar. Active electronic scanning makes it possible to switch radar modes quickly, thereby enabling operational functions to run simultaneously.
Front Sector Optronics – FSO
Developed by THALES, the “Front Sector Optronics” (FSO) system is fully integrated into the aircraft. Operating in the optronic wavelengths, it is immune to radar jamming and it provides covert long-range detection and identification, high resolution angular tracking and laser range-finding for air, sea and ground targets. Using those two optronic channels, the FSO provides day/night, long-range detection, recognition and identification of air, sea and land targets. The FSO does not emit any radiation and is insensitive to jamming. Fully integrated in the aircraft’s nav-attack system, it provides tactical information and target engagement. Its infrared capacities are essential during night flights, in particular for long-range target recognition. The FSO’s powerful TV sensor (cued by the RAFALE’s active and passive sensors) is truly valuable to positively identify targets in situations where a visual contact is required by the rules of engagement.
Front Sector Optronics (FSO) provides a tele-lens picture of the target. It allows target tracking, through IR (Infra-red search and track) and visual sensors: air targets at ranges up to 100 kilometers, surface or sea targets at up to 6 kilometers. The covert approach capability of the FSO is especially valuable in air policing and intercepts, where the TV picture of the target provides early visual identification and detection of suspect manoeuvres. The IR Search and Track channel uses sophisticated processing algorithms for the automatic detection and tracking of airborne threats and targets on the ground.
Air-to-Air and Air-to-Surface Tracking
Infrared Search and Track (Growth potential):
Air-to-Air or Air-to-Surface identification and ranging:
Advantages and functions:
Identification and Tracking:
SPECTRA – internal Electronic Warfare suite
SPECTRA -Self-Protection Equipment to Counter Threats for Rafale Aircraft. Jointly developed by THALES and MBDA, the SPECTRA internal “Electronic Warfare” (EW) system is the cornerstone of the RAFALE’s outstanding survivability against the latest airborne and ground threats. It is fully integrated with other systems in the aircraft, and it provides a multi-spectral threat warning capability against hostile radars, missiles and lasers.
The SPECTRA system carries out reliable long-range detection, identification and localization of threats, allowing the pilot to instantly select the most effective defensive measures based on combinations of radar jamming, infrared or radar decoying and evasive maneuvers. The angular localization performance of the SPECTRA sensors makes it possible to accurately locate ground threats in order to avoid them, or to target them for destruction with precision guided munitions. Additionally, SPECTRA fulfils new functions in a combat aircraft, while significantly participating in the determination of the aircraft's tactical situation, and providing the crew with operational advantage by performing accurate threat location. By virtue of its fully passive situational awareness capability, SPECTRA are a major contributor to the low observability concept of Rafale. SPECTRA gives Rafale firing solution with 1* precision at 200 km.
The outstanding capability of SPECTRA regarding airborne threat localization is one of the keys of the RAFALE’s superior situational awareness. Also instrumental in SPECTRA’s performance is a threat library that can be easily defined, integrated and updated on short notice by users in their own country, and in full autonomy. SPECTRA now include a new generation missile warning system that offers increased detection performance against the latest threats.
Using sophisticated techniques, such as interferometry for high precision DOA and passive ranging, digital frequency memory for signal coherency and active phased-array transmitters for maximum effectiveness and covertness, the highly advanced multi-sensors and artificial intelligence data fusion capabilities of SPECTRA provide the Rafale aircraft with the best chance to survive in harsh and lethal environments. The Rafale combat aircraft and the SPECTRA system are fully operational onboard the French Navy's Rafale.
The SPECTRA system consists of two infrared missile warning sensors (Détecteur de Départ Missile Nouvelle Génération). A new generation missile warning system (DDM NG) is currently being developed by MBDA. DDM NG incorporates a new infrared array detector which enhances performance with regard to the range at which a missile firing will be detected (with two sensors, each equipped with a fish-eye lens, DDM NG provides a spherical field of view around the aircraft). The DDM-NG also offers improved rejection of false alarms and gives an angular localization capability which will be compatible with the future use of Directional Infrared Counter Measures (DIRCM). DDM-NG has an advanced Missile Warning System covering most of the sphere around the aircraft. In particular it provides the capability to detect Manpad missiles by detecting their burning engines. DDM-NG is a passive, imaging infrared Missile Warning System using the latest advances in sensor technology and processing algorithms. The DDM-NG system’s long detection range, spherical field of view and advanced software provides the highest level of performance.
Thales Group and Dassault Aviation have mentioned stealthy jamming modes for the SPECTRA system, to reduce the aircraft's apparent radar signature. It is not known exactly how this work or even if the capability is fully operational, it employs active cancellation technology, such as has been tested by Thales and MBDA. Active cancellation, a unique EW technique that locates an enemy radar in range and bearing, calculates the scatter that it will receive from the Rafale, and transmits an exact mimic of the aircraft’s actual echo — but one-half wavelength out of phase, so that the radar sees nothing.
SPECTRA is divided into different modules and sensors strategically positioned throughout the airframe to provide all-round coverage. The latest advances in micro-electronic technology have led to a new system which is much lighter, more compact and less demanding than its ancestors in terms of electrical and cooling powers.
Heart of the SPECTRA is the GIC computer (Gestion de l'Interface et CompatibilitÃ©) comprising 3 processors.
DBEM (DÃtection et Brouillage ElectromagnÃtique) - RWR/ECM
DDM (DÃ©tecteur infrarouge de DÃ©part de Missiles) - MLD
Data from all the sensor suites are fused and processed by a central computer, which prioritizes and activates the relevant countermeasures, based upon comparison between the received signals and an onboard threat library. RF jamming is transmitted through active phased array antennas. Employment of this advanced technology allows the jamming signal to be concentrated in the sector where it is needed, not only increasing its effectiveness, but also reducing the probability of intercept by the adversary’s own sensors. In addition to RF jammers, the SPECTRA system incorporates mechanical countermeasures for the dispensing of chaff and decoys that are effective in either electromagnetic or infrared domains. In addition to protecting the Rafale, SPECTRA also has a valuable offensive function. Fused data from the sensors provides threat tracks in the weapon system, which can be displayed in the cockpit. These tracks can be used for targeting in the defense suppression role. Additionally, the data product from the SPECTRA sensors is of very high quality, so that the system can be used for the gathering of Elint (electronic intelligence). Pop-up threats can be compared against the threat library, which can be updated with new information. The product of SPECTRA is also recorded and can be downloaded upon the aircraft’s return to base for more detailed analysis in the ground-based support centre. In this way master threat libraries can be updated, and revised data files produced for subsequent missions.
The net-centric capability of the RAFALE hinges on its open architecture, its data fusion software and its compatibility with a variety of data links, which “plug” the RAFALE into the integrated battlespace .A secure high-rate data link is provided to share data in combined air operations in real time with other aircraft in the formation, airborne and surface command and control centre’s, tactical air controllers or other friendly assets. The Link 16 data link is also available to those customers cleared to operate it. As a net-centric capable asset, the RAFALE can exchange images. The Rover (“Remotely Operated Video Enhanced Receiver”) is an element of this capability which allows aircrews and forward air controllers on the ground to share videos or images of the target. It helps prevent blue-on-blue incidents and collateral damage, a decisive advantage in peacekeeping operations.
DAMOCLES and TALIOS- Laser designation pods
The DAMOCLES laser designator pod designed by THALES brings full day and night laser designation capability to the RAFALE, with metric precision. It permits laser-guided weapons to be delivered at stand-off range and altitude. The IR sensor of the DAMOCLES pod operates in the mid-wave infrared band, allowing it to retain its effectiveness in warm and / or humid conditions. DAMOCLES is interoperable with all existing laser-guided weapons. THALES is now working on TALIOS, a new generation multifunction targeting pod.
TALIOS is an acronym for Targeting Long-range Identification Optronic System. It is follow-on from the company’s Damocles navigation and targeting pod, for which Thales took 120 orders, two-thirds of them for export.
Like other such pods from competing suppliers, operators found a new role for Damocles as an imagery sensor–the so-called Non-Traditional Intelligence, Surveillance and Reconnaissance (NTISR) role. Thales says that in designing TALIOS with the latest sensors and stabilization techniques, and by adding a third optical window, it has eliminated some of the shortcomings of previous pods when collecting imagery. For instance, it has a wide field of view, and is able to operate throughout the mission.
Further, Thales claims that TALIOS is the only pod to provide color imagery to NATO standards, while other new features include day or night operation from any altitude; scene-matching; and automatic detection and tracking of mobile targets. TALIOS was previously known as the Pod de Désignation Laser de Nouvelle Génération (PDL-NG). The TALIOS pod is the same shape as Damocles, and approximately the same weight, and can therefore be substituted easily.
AREOS – Recce pod with Quick Analysis Capability
AREOS - Airborne REcce Observation
For both strategic and tactical reconnaissance missions, the French Armed Forces have adopted the new generation THALES AREOS reconnaissance system for the RAFALE.As demonstrated in Libya, Mali, the Central African Republic and Iraq, this high-tech, day and night equipment can be used in a wide range of scenarios, from stand-off distance at high altitude down to high speed and extremely low-level. To shorten the intelligence gathering cycle and accelerate the tempo of operations, the AREOS pod is fitted with a data link which allows high resolution images to be transmitted back to military decision makers in real time. The outstanding performance of AREOS in stand-off reconnaissance makes it a sensor with a true pre-strategic value. It can flight up to 600 knots, and can withstand the shock of carrier operations.
The pod can be operated in fully autonomous mode, without any intervention by the crew. The AREOS Reco NG pod is 4.6 meters long (15 ft.) and weighs 1,100 kg (2,420 lb), making it compatible with the Rafale, as well as the Mirage 2000 if needed. Up front on the pod, the HA/MA (high altitude/medium altitude) optical sensor supports photography at medium range, or even long-range at standoff distance. The AREOS Reco NG offers an identification range of several tens of kilometres – two to three times the range of the Presto pod currently deployed on Mirage F1CR aircraft in Afghanistan.
Located aft in the AREOS pod, the low-altitude sensor supports horizon to horizon photography at an altitude of only 60 meters (200 ft) and very high speeds. The pod operates automatically, whether working in intermittent, zone coverage or terrain-following mode, and always knows its exact position in space, so that it can control the pointing of its optical sensors in both pitch and roll. Its control capability is based on data transmitted by its own inertial reference system, correlated with data from the nav-attack system on the aircraft itself. As soon as the shots are taken, they are automatically overlaid on a digital elevation model, geo-referenced and assembled to provide a complete mosaic of the target. For greater flexibility and coverage, the optics move fore-and-aft within the head of the rotating pod.
The images are then stored on a hard disk in the pod. They can be transmitted to a ground image receiving and processing station in real time, via a high-speed microwave link.The recce pod can also operate in video mode by using successive images and by measuring the displacement of a moving object from one image to another, it can estimate its speed. Battlefield trials based on a hundred test flights enabled the CEAM military aircraft test center to validate the operation of the sensors and their tactical use in conjunction with the Rafale. Test flights covered the full range of scenarios, from conventional to unusual, including tests of opportunity targets involving aircraft being reassigned in the middle of their sortie, through the L16 datalink.
The pod is very easy to operate the crew sees a pointer on their digital map with a mission request. All they have to do is indicate that they accept the mission and slave the pod to the pointer. It’s fast, easy, and there’s no risk of a misunderstanding, since no radio communications are involved.
One of the limitations of imaging-cum-targeting pods has been the need for aircrew to slew the pod-head to the area of interest, and then switch from wide to narrow field-of-view for positive identification and designation of targets. In so doing, situational awareness can be lost.
Thales claims that it has a unique solution, which it has named Permanent View, with geo-referenced imagery from a wide area that is likely to be covered on the mission is stored in the pod. If (for instance) a pilot sees an explosion on the ground or is informed of a target by troops-in-contact, he can arrange to see the surrounding terrain on a cockpit display, with the pod’s field-of-view indicated at center-screen.
This makes slewing the pod easier, and also helps the pilot avoid maneuvers that might temporarily mask the target.
The sheer power of multi-sensor data fusion
In essence, the “multi-sensor data fusion” concept implemented into the RAFALE allows the pilot to act as a true “tactical decision maker”, rather than being only a sensor operator.
PCWRITE - This combination of "letters" appears in the lower left corner of the HLD - Head Level Display, giving a real-time and instant confirmation of which sensors are signaling at that moment. Each letter representing either the RBE2 AESA radar, the Infrared / Laser / TV Front-Sector Optronics (FSO), the internal system of electronic warfare SPECTRA EW, IFF (identification friend-or-foe), and data link are merged into a unified and clear visual symbolism directly on the SA display (situational awareness), and that means keeping the pilot in the situational loop. Rarely (not witnessed at any time during our evaluations) would the pilot ever be unaware of the environment within the 360º “bubble” surrounding the aircraft. The core of these enhanced capabilities of the RAFALE lays in a new “Modular Data processing unit” (MDPU) incorporating “commercial off the shelf” (COTS) elements. It is composed of up to 19 flight “line-replaceable units” (LRUs), with 18 of them individually providing 50 times the processing power of a typical mission computer employed in previous generation fighters. The MDPU is the cornerstone of the upgradeability of the RAFALE. It allows a seamless integration of new weapons and new capabilities to maintain the war fighting relevance of the RAFALE over the years as tactical requirements evolve, and as the computer industry keeps rolling out new generations of processors and software.
The “multi-sensor data fusion” provides a link between the battle-space surrounding the aircraft and the pilot’s brain with its unique ability to grasp the outcome of tactical situations and make sensible decisions. It hinges on the computing power of the MDPU to process data from the RBE2-AESA radar, the “Front Sector Optronic” (FSO) system, the SPECTRA EW system, the IFF, the MICA infrared seekers, and the data link.
Implementation of the “multi-sensor data fusion” into the RAFALE translates into accurate, reliable and strong tracks, uncluttered displays, reduced pilot workload, quicker pilot response, and eventually into increased situational awareness.
It is a full automated process carried out in three steps:
A unique “Man-Machine Interface” (MMI)
DASSAULT AVIATION has developed a very easy to use pilot interface (MMI), combining the “Hands on Throttle and Stick” (HOTAS) control concept with touch screens. It relies on a highly integrated suite of equipment with the following capabilities:
The comprehensive design of the cockpit provides for everything that aircrews can expect from an “OMNIROLE” fighter: a wide field of view at the front, on both sides, and at the rear, a superior agility, an increased G-protection with 29° tilted seats, and an efficient air conditioning system demonstrated under all climates.
The Rafale's glass cockpit was designed around the principle of data fusion – a central computer intelligently selects and prioritizes information to display to pilots for simpler command and control. The primary flight controls are arranged in a hands-on-throttle-and-stick (HOTAS)-compatible configuration, with a right-handed side-stick controller and a left-handed throttle. The seat is inclined rearwards at an angle of 29° to improve g-force tolerance during maneuvering and to provide a less restricted external pilot view.An intelligent flight suit worn by the pilot is automatically controlled by the aircraft to counteract in response to calculated g-forces. Dassault also plans to introduce an automatic "g-loc" recovery mode. It has framed canopy providing 360* horizontal and 197,7* vertical visibility, including 16* over the nose, 1,7* over the tail and 27* over the sides, with a maximum of 54* over the side visibility.
Great emphasis has been placed on pilot workload minimization across all operations. Among the features of the highly digitized cockpit is an integrated direct voice input (DVI) system, allowing a range of aircraft functions to be controlled by spoken voice commands, simplifying the pilot's access to many of the controls. Developed by Crouzet, the DVI is capable of managing radio communications and countermeasures systems, the selection of armaments and radar modes, and controlling navigational functions. For safety reasons, DVI is deliberately not employed for safety-critical elements of the aircraft's operation, such as the final release of armaments.
For displaying information gathered from a range of sensors across the aircraft, the cockpit features a wide-angle holographic head-up display (HUD) system, two head-down flat-panel color multi-function displays (MFDs) as well as a central collimated display. These displays have been strategically placed to minimize pilot distraction from the external environment. Some displays feature a touch interface for ease of Human–computer interaction (HCI). A head-mounted display (HMD) remains to be integrated to take full advantage of its MICA missiles. The cockpit is fully compatible with night vision goggles (NVG).
Entry and exit to the B/C models is via a ground crew-positioned vertical ladder, but the M model has an integral drop-down step. Seat height and rudder pedal adjustment is electric, and the cockpit is a classic fighter "snug" fit, but with all the required flight switches forward of the 3-9 body line. The single throttle and sidestick controller contain over 34 separate switches, many with multifunctions, but the main switches such as airbrake, radio telecommunications, auto pilot and auto throttle were "chunky" and easy to differentiate.
The left and right lateral head-down display screens were touch sensitive with additional L/R rotary and L/R finger switches to designate and control display modes. The head-level display (HLD) allowed for a wide-angle view of the tactical situation and is focused at infinity, so there is no need to refocus your eyes when scanning rapidly between head-up and head-level. Advances in display technology may enable a future HLD to retain the same advantages in a more flat panel display and give more cockpit space.
The wide-angle (30° x 20°) holographic HUD meant the displayed symbology was delightfully uncluttered and sharply focused and could be viewed completely without any head movement away from a design eye point position.
After the sideways-hinged canopy (designed to allow for unrestricted ejection seat removal if required) was closed electrically and with a rapid engine start using the auxiliary power unit completed, it only take about 90s ready to taxi after engine stabilization. Taxi speed can easily control, because the residual ground thrust is limited by keeping both "mini-throttles" (acting as low-pressure cocks) in the "idle" position before setting them to "normal" for take-off. Ground steering was highly accurate and responsive, and the brakes were very smooth and progressive.
Safety of Pilots
Pilot safety is safeguarded by various systems of the Rafale. Starting with the seat, a tilt of 29º distributes the gravitational effect, preventing G-Loc; even at 9Gs that Dassault’s fighter can pull without surpass the operational load factors parameters, in air-to-air mode. The GPW - Ground Proximity Warning, alerts by audible and visual signals, to avoid colliding with the ground when the attitude and altitude of flight correspond to an approach to the surface. If needed, a pre-programmed recovery system can be accessed by the pilot, and in the case of spatial disorientation, there is an "anti-spin” feature even though the Rafale has not shown any tendency to spin, even in the corners of the envelope. Nevertheless, once anti-spin switch is activated, the flight computers redirect the aircraft to a safe flight regime with wings leveled, 5 degrees of climb, and 350 kts. In the absence of reaction by the pilot, GPW will also automatically initiate a maneuver leading back to the leveling of the airplane’s wings and a positive attitude to climb. If Rafale safety features prevents CFIT events (controlled flight into terrain), it is exactly on the low flight (close to the ground - hilly or flat - or water) that the fighter shows one of its greatest strengths. With a unique capability and clever use of Terrain Following mode is much more than an aid to agile piloting at very low altitude.It acts as an extra pilot in the cockpit, since the security in the fidelity of the system - which combines the redundancy of AESA radar and the digital database, leave pilot entirely focused on the tactical objective of the mission: namely, to deliver the "package" in the right place at the right time... and yet, track airborne targets and threats during the raid.
An on-board oxygen generating system, developed by Air Liquide, eliminates the need to carry bulky oxygen canisters. The Rafale's flight computer has been programmed to counteract pilot disorientation and to employ automatic recovery of the aircraft during negative flight conditions. The auto-pilot and auto throttle controls are also integrated, and are activated by switches located on the primary flight controls.
A full range of advanced weapons
Initial deliveries of the Rafale M were to the F1 ("France 1") standard, these had been equipped for the air-to-air interceptor combat duties, but lacked any armaments for air-to-ground operations. Later deliveries were to the "F2" standard, which added the capability for conducting both air-to-ground and reconnaissance operations; the first F2 standard Rafale M was delivered to the French Navy in May 2006. Starting in 2008 onwards, Rafale deliveries have been to the nuclear-capable F3 standard, and it has been reported that all aircraft built to the earlier F1 and F2 standards are to be upgraded to become F3s. The mission system of the RAFALE has the potential to integrate a variety of current and future armaments.
The RAFALE’s stores management system is Mil-Std-1760 compliant, which provides for easy integration of customer-selected weapons. With its 10-tonne empty weight, the RAFALE is fitted with 14 hard points (13 on the RAFALE M). Five of them are capable of drop tanks and heavy ordnance. Total external load capacity is more than nine tonnes (20,000 lbs.). “Buddy-buddy” refuelling missions can be carried out in portions of the airspace out of reach of dedicated and vulnerable tanker aircraft.
With its outstanding load-carrying capability and its advanced mission system, the RAFALE can carry out air-to-ground strikes, as well as air-to-air attacks and interceptions during the same sortie. It is capable of performing several actions at the same time, such as firing air-to-air missiles during a very low altitude penetration phase: a clear demonstration of the true “OMNIROLE” capability and outstanding survivability of the RAFALE.
Guns: 1× 30 mm (1.18 in) GIAT 30/M791 autocannon with 125 rounds
Rafale has the biggest gun on the market (ex aequo with Sukhoi aircraft): a hefty 30mm GIAT gun firing incendiary rounds. This makes the Rafale an excellent choice for both air to air and air to ground combat, as its 30mm rounds would provide excellent support for troops on the ground. 30mm is the caliber of the guns of most APCs and IFVs.
The MBDA MICA is an anti-air multi-target, all weather, fire-and-forget short and medium-range missile system. It is intended for use both by air platforms as individual missiles as well as ground units and ships, which can be equipped with the rapid fire MICA Vertical Launch System. It is fitted with a thrust vector control (TVC) system Range Air-launched 0.2–50 km at Mach 4.
Exocet AM39 is the airborne version of the Exocet anti-ship missile family. It can be launched from strike aircraft, Maritime Patrol Aircraft and helicopters. With a range of up to 70 km, depending on the altitude and speed of the aircraft, the Exocet AM39 enables the aircraft to remain at range from enemy air defenses. When carrying out a low altitude attack, the missile may also be launched under the target ship radar coverage. Ingress is at a very low altitude over the sea (sea skimming).
Built-in ssup portability
The RAFALE supportability and mission readiness claims are supported by the undisputed track record of the earlier generation of French fighters, such as the combat-proven MIRAGE 2000. From the early beginning of the development phase, the French MoD assigned very stringent “integrated logistic support” (ILS) requirements to the RAFALE programme. “Computer aided design” (CAD) with the Dassault Systèmes CATIA software suite, concurrent engineering and bold technological choices ultimately produced an ILS system that exceeds the original supportability requirements.
The following examples, selected from a range of unique and innovative features, demonstrate the advance in reliability, accessibility and maintainability brought by the RAFALE:
From 2006 to 2011, French Air Force and Navy RAFALE fighters were engaged in countless combat missions in Afghanistan where they demonstrated a very high proficiency and a tangible military value. The AASM/HAMMER precision-guided modular air-to-surface armament, PAVEWAY laser-guided bombs, and the 30 mm cannon were employed on many occasions, scoring direct hits with remarkable precision.
In 2011, French Air Force and French Navy RAFALE fighters were successfully engaged in coalition operations over Libya. They were the first fighters to operate over Benghazi and Tripoli, and they carried out the whole spectrum of missions the RAFALE was designed for: air-superiority, precision strikes with HAMMERS and laser-guided bombs, deep strike with SCALP cruise missiles, Intelligence, Surveillance, Tactical Acquisition and Reconnaissance (ISTAR) and Strike Coordination And Reconnaissance (SCAR). During the Libyan conflict, hundreds of targets – tanks, armored vehicles, artillery emplacements, storage dumps, command centres and air-defense systems (SA-3 Goa and SA-8 Gecko fixed and mobile SAM launchers) – were hit with devastating accuracy by RAFALE aircrews.
French Air Force RAFALES have taken a leading role in Mali, helping destroy enemy infrastructure and support friendly troops in contact. Four RAFALES undertook the longest raid in French Air Force history, taking off from Saint-Dizier, in eastern France, and landing in N’Djamena, in Chad, after hitting 21 targets and spending no less than 9 h 35 min airborne. The French Air Force quickly set up a forward operating base in Chad, and the RAFALE detachment later grew to eight aircraft. This represented the first time the RAFALE had operated from a FOB in Africa.
More recently, RAFALES were engaged in support of peace-keeping operations in the Central African Republic, and as part of a wide international coalition in Iraq.
Courtesy :- Official Websites of Dassault , Thales, MBDA
:- Wikipedia and many other internet resources
A rocket engine is a type of jet engine that uses only stored rocket propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines, obtaining thrust in accordance with Newton's third law. Rocket thrust results from the high speed ejection of material and does not require any medium to "push against", so they are well suited for uses at very high altitude and in space. There are two main categories of rocket engines; liquid rockets and solid rockets. Under normal temperature conditions, the propellants do not burn; but they will burn when exposed to a source of heat provided by an igniter.
A) Solid fuel rockets
Solid-fuel rocket engines were the first engines created by man. Solid rocket engines are used on air-to-air and air-to-ground missiles, on model rockets, and as boosters for satellite launchers. In a solid rocket, the fuel and oxidizer are mixed together and packed into a solid cylinder. Once the burning starts, it proceeds until all the propellant is exhausted. With a liquid rocket, you can stop the thrust by turning off the flow of propellants; but with a solid rocket, you have to destroy the casing to stop the engine. One of the biggest problems with solid fuel rocket engines is that once started, the reaction cannot be stopped or restarted. This makes them considered uncontrollable. Therefore, solid fuel rockets are more widely used for missiles, or as booster rockets. A solid rocket is much easier to handle and can sit for years before firing.
A hole through the cylinder serves as a combustion chamber. When the mixture is ignited, combustion takes place on the surface of the propellant. A flame front (the surface of the interface that faces reactants is often termed as the flame front. Similarly, the surface the faces the products can be termed as the flame back) is generated which burns into the mixture. The combustion produces great amounts of exhaust gas at high temperature and pressure. The amount of exhaust gas that is produced depends on the area of the flame front and engine designers use a variety of hole shapes to control the change in thrust for a particular engine. The hot exhaust gas is passed through a nozzle which accelerates
B) Liquid fuel rockets
In a liquid rocket, the propellants, the fuel and the oxidizer, are stored separately as liquids and are pumped into the combustion chamber of the nozzle where burning occurs. Liquid rockets tend to be heavier and more complex because of the pumps and storage tanks. The propellants are loaded into the rocket just before launch. Liquid rocket engines are used on the Space Shuttle to place humans in orbit, on many un-manned missiles to place satellites in orbit, and on several high speed research aircraft following World War II
All liquid rocket engines have tankage and pipes to store and transfer propellant, an injector system, a combustion chamber which is very typically cylindrical, and one (sometimes two or more) rocket nozzles. Liquid systems enable higher specific impulse than solids and hybrid rocket engines and can provide very high tankage efficiency.
Liquid rockets can be mono-propellant rockets using a single type of propellant, bi-propellant rockets using two types of propellant, or more exotic tri-propellant rockets using three types of propellant.
According to the type of propellants used in the rockets we can classify liquid fuel rocket engines into cryogenic, Semi cryogenic & hypergolic
A cryogenic engine uses cryogenic fuels. A cryogenic technology is the process of involvement or including of usage of rocket propellants at a cryogenic temperature. It can be combination of liquid fuels such as: liquid Oxygen (LOX), and liquid Hydrogen (LH2) as an oxidizer and fuel in the different mixtures or proportions. The mixture of fuels offer the highest energy efficiency for the rocket engines that produces very high amount of thrust. Here, the Oxygen remains liquid only at the temperature below (-183 C) and Hydrogen below (-253 C). This is a type of rocket engine that is functionally designed to use the oxidizer which must be refrigerated in the liquid state. Sometimes, the liquid nitrogen (LN2) is used as a fuel because the exhaust is also nitrogen.
The engine components are also cooled so the fuel doesn’t boil to a gas in the lines that feed the engine. The thrust comes from the rapid expansion from liquid to gas with the gas emerging from the motor at very high speed. The energy needed to heat the fuels comes from burning them, once they are gases. Cryogenic engines are the highest performing rocket motors. One disadvantage is that the fuel tanks tend to be bulky and require heavy insulation to store the propellants. Their high fuel efficiency, however, outweighs this disadvantage.
A Cryogenic rocket stage is more efficient and provides more thrust for every kilogram of propellant it burns compared to solid and earth-storable liquid propellant rocket stages. Specific impulse (a measure of the efficiency) achievable with cryogenic propellants (liquid Hydrogen and liquid Oxygen) is much higher compared to earth storable liquid and solid propellants, giving it a substantial payload advantage.
Dont forget to see this awesome video by ISRO - https://www.youtube.com/watch?v=nfZBIHGAiuk
Semi cryogenic engines using liquid oxygen and kerosene as propellants. They are considered relatively environment friendly, non-toxic and non corrosive. In addition, the propellants for semi-cryogenic engine are safer to handle & store. It will also reduce the cost of launch operations. Apart from this combination of Liquid oxygen (LOX) and alcohol (ethanol, C2H5OH) Liquid oxygen (LOX) and gasoline , Liquid oxygen (LOX) and carbon monoxide.
The main difference between cryogenic and semi cryogenic engine is its fuel. Cryogenic engine has better specific impulse than semi cryogenic engine so it is ideal for upper stages of rockets. Semi-cryogenic engines offer the best thrust to weight ratios , higher density of the exhaust gases of the semi-cryogenic contribute to high mass flow rates making it easier to develop high thrust engines. So semi cryogenic engine is ideal for lower stages.
A hypergolic propellant combination used in a rocket engine is one whose components spontaneously ignite when they come into contact with each other. The two propellant components usually consist of a fuel and an oxidizer. Although commonly used hypergolic propellants are difficult to handle because of their extreme toxicity and corrosiveness, they can be stored as liquids at room temperature and hypergolic engines are easy to ignite reliably and repeatedly.
Rocket engine, where a solid fuel is combined with a liquid oxidizer or vice versa, is known as a hybrid rocket. Hybrid rockets avoid some of the disadvantages of solid rockets like the dangers of propellant handling, while also avoiding some disadvantages of liquid rockets like their mechanical complexity.
Fuselage IR radiance consist of emission by virtue of its temperature, reflected earth shine, sky shine & sun light. For a low flying aircraft, even if the rear fuselage emissivity is made zero, the air craft can still be locked on by SAM, due to the reflected earth shine in 8-12 micrometer. In the absence of earth shine, negative contrast with the background sky radiance can be used for air craft detection & lock on. Matching of fuselage IR emissions with those of the background is a high potential technique for IR camouflage. The IRSS system for fuselage can be grouped in 2 categories
AIRCRAFT SKIN HEATING/COOLING
Air craft uses a system for electrical heating of the upper portion of the fuselage for background matching. The negative IR contrast of the aircraft with respect to the surroundings is minimized there by providing IR camouflage when viewed by aircraft flying at higher altitudes. However heating is less often applicable; instead cooling of the aerodynamically heated fuselage skin especially at high mach no is more often applicable. Cooling of the skin to a temperature near the ambient air will reduce the detection range by IR imaging scanners. Heat pipe cooling & liquid evaporative cooling of aircraft skin from inside & heating/cooling of surfaces by thermo couples were patented as IRSS system. In such systems the background temperature is sensed & the aircraft skin heated/ cooled to the same temperature resulting in IR camouflage. The skin is heated or cooled using a thermo electric module that converts electrical energy into a temperature gradient. By application of voltage across the modules one side of the module becomes hot & the other side becomes cold. The temperature of the adjacent surface can be controlled by varying the applied voltage.
The aircrafts IR radiance strongly depends on the emissivity of the radiating surface; which depends on surface temperature & surface physical & chemical properties. Most methods of IRSS are associated with performance penalties e.g. Increased drag, additional weight, increased RCS; increased nozzle back pressure etc. emissivity optimization of the aircraft surface is a viable option which does not impose performance penalties. Rear fuselage emissivity optimization in the 3-5 & 8-12 band emissivity reduction from 1.0 to 0.0 reduces peak aircraft spectral lock on range by almost 100% in the 8-12 micrometer bands. It is seen that lock on range is more sensitive in 8-12 band as compared to 3-5 band. Emissivity can be optimized by physical & chemical treatment of the radiating surfaces.
SOME TECHNIQUES TO EMISSIVITY OPTIMIZATION
LIMITATIONS OF IR SUPPRESSORS
Passive IRCM’s can be incorporated on an aircraft in the initial design or modification stage or later as retrofits/additives. First gen IR suppressors were simple & aimed to provide optical blockage of hot engine parts. 2nd gen IR suppressors involve a combination of optical blockage, metal cooling & exhaust gas cooling which add more complexity to the system. The major performance penalties associated with incorporation of IR suppressors are disclosed below
ACTIVE COUNTER MEASURES
These countermeasures include IR jammers and IR flares, which serve as decoys by luring away the approaching heat seeking missile. Saturation jammers introduce large amount of IR noise into the threat’s tracking system that damages the seeker optics. Smart jammers are either non-directional or directional (DIRCM), and deceive IR trackers by sending false target information. The IR flares were used first as active countermeasures against IR seekers in the Vietnam War in the 1960s. These decoys are easy to handle, reliable, and are made of cheap constituents like metal fuels and oxidizers. To imitate the tail-pipe IR spectrum, the decoy flares fired from the rear. Busting smoke of bronze–copper-lined flakes, bronze flakes, and mixture of flakes with chaff, serve as IR decoys for longer duration .However, the new generation of imaging IR detectors can discriminate IR flare (as point source) and target, making flares ineffective as IRCM. To counter this situation, decoys driven by liquid fuels that produce as large a radiating plume as that of aircraft were proposed. Such decoys use more energetic fuels like tri-ethyl-aluminum, tri-isobutyl-aluminum, di-ethyl-aluminum, etc., which are called as pyrophoric liquids
Development of a Missile Approach Warning System (MAWS) against IR-guided missiles is a formidable task. Typical MAWS should ideally have the following characteristics:
There are three technological options available for MAWS
COUNTER COUNTER MEASURES
CCMs are counter the active and passive IRCMs. Some examples of CCM are as follows