[DrPriyankT]

This is my humble effort in describing the genesis of the LCA Tejas program in the IAF, it's capabilities and it's role in the future of the IAF. Be Warned, its a long read! I also request members to give their valuable opinions and more information which I may have missed to add.

LCA TEJAS
The Light Combat Aircraft Project was envisaged in the year 1983 by the DRDO, with an aim to develop a Generation 4 jetfighter, to replace the Mig-21’s. IAF had inducted the Mig-21’s from 1969, and the first aircraft were planned to be replaced by the early 1990’s. However, the genesis of this project had started in the 1970’s right after the development of the HF-24 Marut, which was an otherwise sturdy fighter, let down majorly by its underpowered engines. HAL began design studies with the IAF's new ASR, which called for an air superiority fighter with secondary ground attack - close air support capabilities dubbed as 'Tactical Air Support Aircraft'. The HAL completed design studies for the new Tactical Air Support Aircraft in 1975, but the project fell through due to the inability to procure the selected "proven engine”.
By the time approval was sought for the Tejas in 1983, India already had designed and built the Marut, and already had started license manufacture of the Soviet Mig 21, British Gnat and the Anglo-French Jaguar (just about started by then). This gave DRDO and HAL the confidence that we can build a Gen-4 fighter right from scratch. I would like to point out here that at this time the Chinese too had just license produced various Soviet jets, and they too started the design process for their homegrown J-10 (based on the IAI Lavi) in the 1980’s and look at where they are now. Yes, they begged, borrowed, and stole a few designs, but you must credit them with the fact that they have a Gen-5 fighter ready in the current day, even though they started designing Gen-4 fighters when we started, but that is a discussion for another day.
After GOI’s approval was obtained in 1983, the ball started rolling in 1984, with the establishment of the Aeronautical Development Agency (ADA), which was supposed to the nodal agency for the design of the new jet. However, the first of many delays started as the IAF had not readied and given its ASQR (Airstaff Qualitative Requirements) till October 1985. However, this delay gave ADA time to build up resources, and hire the right people for the job. This project was originally planned to have 1st flight of prototype by 1990, and induction by 1995, when the 1st Mig-21’s would retire.


Image Source: Ain Online

For this project, along with the aircraft, the government envisaged homegrown development of three more critical technologies, that is homegrown digital fly by wire, an afterburning turbofan and a multimode doppler radar. India was successful in developing the fly by wire system ,the turbofan engine being developed was the Kaveri, which even though did not power the LCA, taught us lessons which will help in the development of future gas turbines, and the multimode radar later metamorphized into the AESA Uttam Radar, which is going to be the primary sensor of future Tejas Aircraft (more on it later).

The project was finally in some semblance of motion in 1987, when the project definition phase was commenced in October 1987 with France's Dassault-Breguet Aviation as consultant. No wonder we see the design of the Tejas, that is a delta winged aircraft which resembles a Mirage 2000, all thanks to the influence of Dassault as a consultant. Dassault had offered ADA, its old analogue flight control technology, but ADA insisted on a quadruplex digital fly by wire system, which to its credit, it developed on its own.

In 1989, the GOI, formed a review committee to discuss the feasibility of the Tejas project, and the said committee gave its thumbs up to the project. Then in 1990, a two-stage full-scale engineering development (FSED) process was opted for the development of LCA. Also in 1990, the design was finalised, a small tailless delta wing design with relaxed static stability which incorporates "control configured vehicle" concept and digital FBW flight control system for enhanced manoeuvrability. Again, I would like to insist on how the Tejas derives its design from the favourite go to aircraft of the IAF, the Mirage 2000. Yes, their wings are shaped a bit differently, with the Mirage having clean lines on the leading edges of its low mounted wings and the Tejas has a slight curve on the leading edges of the mid mounted wings, but the similarity in design philosophy shows. Delta wings are generally preferred in interceptor aircrafts like the Mig 21 (which the Tejas was to replace), as they offer lower drag, better low speed angles of attack (however they need powerful engines for this) and in general better manoeuvrability for dog fighting. Also the midmounted wing in the Tejas gives it better low altitude flight characteristics and stability vis a vis the low mounted wing in the Mig-21 and the Mirage 2K, which can be useful for low level ground attack roles.


The legendary Dr.Kota Harinarayana was the original Programme Director and Chief Designer for the Tejas Programme. He steered this mammoth project in its initial tumultuous years, when its design was being frozen, and mission critical technologies were being developed from the ground up. In 1992, the LCA National Control Law (CLAW) team was set up under National Aeronautical Laboratory to develop the complex quadruplex digital fly by wire system for flight control of the Tejas. At that time Lockheed Martin was appointed the consultant for the FBW system being developed, however the contract for the same was terminated in 1998, on account of the post Pokhran sanctions. However, I consider it good riddance, as it forced us to develop our own technology, which will help us in the future as we develop more indigenous aircraft.


Phase 1 of the LCA program commenced in June 1993, and under it, it was envisaged that there would be two technology demonstrator aircraft, namely TD-1 and TD-2. The focus of this phase was to establish proof of concept of the program in the two technology demonstrator aircraft. This was to lead to the development of PV-1 and 2 (Prototype Variant). NAL's CLAW team completed the integration of the flight control laws with the flight control system software performing flawlessly for over 50 hours of pilot testing on TD-1, and the TD-1 finally flew with an indigenous FBW flight control system on its maiden flight on 4 January 2001. The successful 1st flight of TD-1 by Wing Commander Rajiv Kothiyal started the end of phase 1 of the LCA program. Phase 2 of the programme was commenced in November 2001 which envisaged the manufacturing of three more prototypes - a production standard air force variant, a naval variant, and a trainer variant, in addition to the replacement of imported Line-replaceable units (LRU) with indigenous LRUs.
The main powerplant of the Tejas is the General Electric F404 engine. Originally, the Tejas was intended to be powered by the desi GTRE Kaveri engine, but the difficulties of developing a jet engine were too much for DRDO and HAL, and hence we had to depend upon the American Engine to power our desi fighter. However, since data is available publicly for the reasons of the failure of the LCA, we cannot say with certainty what caused DRDO to abandon the Kaveri for the Tejas, but I am sure our scientists and engineers must have learnt a lot of lessons even though the Kaveri as an operational aeroengine did see the light of day. Kaveri engine can be discussed in another post if members are interested. Here I would like to mention that China despite all their technological prowess and industrial espionage have not still been able to create a military turbofan which can match a Russian engine, leave alone American and European engines. Their WS-10 engine (based on the CFM-56 core) still cannot match the Russian AL-31/41 Engines. The selection of the American engine hamstrung our Tejas as we lost American support for the F-404 from 1998 to 2004 when ties thawed. In 2004, General Electric was awarded a US$105 million contract for 17 uprated F404-GE-IN20 engines to power the eight air force and two naval prototypes for which deliveries began in 2006. In 2008, HAL placed an order for additional 24 F404 IN20 engines to power production Tejas Mark 1 fighters. The higher power F414 has been selected for Tejas Mk2 aka MWF.


After the turbofan engine and the fly by wire system, a pulse doppler multimode radar completed the trio of critical technologies being co-developed with the LCA. Initially, the Ericsson/Ferranti PS-05/A I/J-band multi-function radar, also used on Saab's JAS 39 Gripen, was intended to be used. However, by then DRDO had developed quite a few phased array radars for the indigenous SAM systems like the Rajendra Radar for the Aakash and the INDRA radar, which gave them the belief that they could develop a homegrown radar for a fighter plane. HAL's Hyderabad division and the DRDO's Electronics and Radar Development Establishment (LRDE) laboratory were selected to jointly lead the MMR programme, and work commenced in 1997. The Centre for Airborne Systems (CABS) was responsible for the MMR's test programme. Between 1996 and 1997, CABS converted the surviving HAL/HS-748M Airborne Surveillance Post into a testbed for the LCA's avionics and radar. By mid-2002, the MMR had reportedly suffered major delays and cost escalations. By early 2005, only the air-to-air look-up and look-down modes — two basic modes — were confirmed to have been successfully tested. In May 2006, it was revealed that the performance of several modes being tested “fell short of expectations’’. The problem with the radar was mainly attributed to the compatibility issue arose between the LRDE/HAL multi-mode radar and the LRDE's advanced signal processor module. Using an "off-the-shelf" foreign radar as an interim option was being considered. The multimode radar, procured for the initial LCA Mk1’s was the EL/M-2032, produced by ELTA of Israel. It will be used for the 40 Tejas Mk 1 (IOC and FOC) aircraft, along with the 10 Tejas twin seat trainers. ELTA EL/M-2052 AESA (Active Electronically Scanned Array) will be used for the 1st 20 of the 83 MK1A aircraft, while the next 63 aircraft will be equipped with the indigenous Uttam AESA Radar.
Uttam AESA radar is a Liquid Cooled Gallium Arsenide based radar, developed by LRDE. It is a scalable radar, whose TR (Transmitter-Receiver) modules can be increased in number to make more powerful radars to fit into nose cones of larger aircraft. Three units are in various phases of testing, as of 2021. Uttam AESA radar has completed 230 hours of airborne testing onboard two Tejas fighter jets (LSP2 and LSP3) beside an executive jet; presumed to be DRDO's Dornier 228 "Nabhratna" used as a flying test bed by LRDE. Once fully validated and certified, plan is to introduce the radar in later batches of Tejas Mark 1A aircraft from the 21st production aircraft. It will be integrated into DRDO’s unified electronic warfare platform which will be the core of the EW abilities of future aircraft. Scaled up Uttam’s will be used for the Tejas Mk2 aircraft, Twin Engine Deck borne fighter and AMCA. It is also envisaged that the Uttam will be used for the upgrade of the Su-30 MKI, where it’s large radome will house an Uttam with more than 1500 TR modules making it a beast of a radar. Uttam will have 18 modes, and in the future if things go according to plan DARE will update the radar to Gallium Nitride based array. As per recent reports, the scaled up Uttam in LCA Mk 2 will have 1260 TR modules, and it will be integrated to the unified electronic warfare suite being developed by DARE. It will be akin to the SPECTRA EW warfare suite in the Rafale’s. Such an integrated EW suite in the Tejas Mk2, combined with the Rudram missile will make it a potent Wild Weasel Aircraft.


An interesting successful spin-off of the LCA program has been the development of a profitable commercial spin-off in its Autolay integrated automated software for designing 3-D laminated composite elements (which has been licensed to both Airbus and Infosys). The successful endeavours were the development and manufacturing of carbon-fibre composite structures and skins, and a modern glass cockpit. The Su-30 MKI manufacture in India has given HAL massive experience in manufacture of Titanium Alloy based aircraft, whereas experience in manufacture of Tejas which is heavy on carbon composite bodes well for future aircraft to be made in India.
This Wikipedia link will give those interested a concise and brief timeline of the development of the Tejas. https://en.wikipedia.org/wiki/Timeline_of_HAL_Tejas

[DrPriyankT]

General Design Characteristics of the Tejas

The Tejas is what aerospace engineers and designers will call a single-engine multirole fighter which features a tailless, compound delta wing design. This compound delta wing design will give it good maneuverability, good high speed, high alpha performance as compared to conventional cruciform winged aircraft. It is designed with relaxed static stability which makes it a very agile aircraft. However, like all delta winged fighters, it will be deadliest in single turn dogfights, however, in sustained turn dogfights, due to its large wings, it will bleed energy faster, however in a dogfighting configuration, the Tejas will have sufficient reserve engine thrust to gain back energy. This will be partially solved with Tejas Mk2 which is designed to have a sustained turn rate of 18 degrees per second. It’s canards too will help mitigate energy loss, whilst improving low speed handling. The tailless compound delta winged aircraft are designed to be small and lightweight, which at the same time reduces the number of control surfaces on the aircraft. Tejas has no fore-planes or tail-planes, but just a single vertical tail-fin. Extensive wind tunnel testing and advanced computational fluid dynamics have optimised the aerodynamic configuration for minimum supersonic drag, a low wing-loading, and high rates of roll and pitch. It is constructed of lightweight aluminium-lithium alloys, carbon fire composites and titanium alloys. 45% of its total weight and 90% of its surface area is made of carbon fiber composites. Upper and lower wing skins are manufactured from a single piece of carbon-fibre reinforced polymer. Wing spars and ribs are also made from carbon composites. The construction of elevons, tailfin, rudder, air brakes and landing gear doors use co-cured and co-bonded manufacturing techniques. The radome is made from Kevlar, while the fin tip is made of glass-fibre reinforced plastic. We can proudly say that the percentage of composites used in the Tejas is one of the highest amongst fighters of its class. The wing and fin of the compound-delta aircraft are of carbon-fibre-reinforced polymer and were designed to provide a minimum weight structure and to serve as integral fuel tanks. The tailfin is a monolithic honeycomb structure piece, reducing the manufacturing cost by 80% compared to the "subtractive" or "deductive" method, involving the carving out of a block of titanium alloy by a computerized numerically controlled machine. No other manufacturer is known to have made fins out of a single piece. Mastery of this complex manufacturing process will pay dividends during manufacture of AMCA and TEDBF.


Image source: Jet Photos

The Tejas Mk 2 will be lengthened by about 1.2 meters to accommodate the bigger engine, to carry more fuel and to increase space for avionics. It will have close coupled canards for better low speed handling. It will be in the 17.5 ton weight category, and as compared to the Tejas Mk1, it will have 11 hardpoints (including wingtip pylons) and its internal fuel carrying capacity will be 1.5 tonnes more than the Tejas Mk1.


The extensive use of carbon composites, especially with 90% of its surface area being made of it, confers upon the aircraft a significantly lowered radar cross section as compared to aircraft of its class made predominantly out of metal alloys. Obviously, the exact RCS figures are kept closely guarded secrets, but common sense dictates that the Tejas will have one of the lowest RCS amongst our fleet. Also, its Y-duct inlet which shields the engine compressor blades from probing radar waves reduces the frontal radar cross section. The use of Radar Absorbent Material makes it even more stealthy. Its small size and inherently low RCS could make it the Ninja of our fleet. The air-intakes are differently designed in the Tejas Mk2 to cater for increased airflow requirements of the bigger GE F414 engine.


If the naval variant of the of the Tejas were to see the light of day (in terms of production), for performing carrier landings where low speed handling is the clincher, it would have had wing leading–edge vortex controllers (LEVCON) which could be deflected to 25 degree downward angle and up to 30 degree upward angle to increase lift and reduce airspeed during approach. The LEVCONs are control surfaces that extend from the wing-root leading edge and thus afford better low-speed handling for the LCA Navy, which would otherwise be compromised by the increased drag that results from its delta-wing design. The LEVCONs should also increase controllability at high angles of attack (AoA). It also has strengthened landing gear to take the shocks of controlled crash landings, also known as carrier arrested landings, it has a strengthened undercarriage, an arrester hook and a powered nosewheel for on deck manoeuvrability. The Tejas trainer variant will have aerodynamic similarity with the Tejas Naval Variant.



Tejas Naval Variant taking off from shore based test facility at IMS Hansa Goa



A closer look at the Tejas Naval Variant - The trainer will appear quite similar to this

[DrPriyankT]

Avionics of the Tejas

The cockpit of the Tejas has quite a few made in India components. The Heads Up Display is designed by the Central Scientific Instruments Organization. The cockpit also has three full colour 5 inch by 5 inch displays, accompanied by 2 smart standby displays will provide key tactical data needed by the pilot for his/her mission along with basic flight data. The pilot will interact with the control systems via a keyboard and multiple selection panels. BEL has developed a ‘get-me-home’ unit, wherein the ail-operational/fail-safe air data computer manufactured by BEL uses computational intelligence based autoland system to provide the pilot with essential flight information in case of an emergency. For life support, the Mk1 fighters will depend on LOX containers to provide pilots with oxygen to breathe, whereas in MK1A, DRDO has developed an onboard oxygen generating system (OBOGS). The technology used for this OBOGS was scaled up and used to generate oxygen in hospitals during the 2nd wave of the Wuhan Virus Pandemic. Tejas uses the Elbit Dash-4 helmet which is helmet mounted display and sight, along with a hands on throttle and stick (HOTAS), along with it’s Heads Up Display to reduce pilot workload and increase situation awareness by allowing access to navigation and weapon cueing information with minimal need to spend time "head down" in the cockpit. The pilot sits on a Martin-Baker 6LG zero-zero ejection seat and DRDO integrated an indigenous canopy severance system (CSS) in the Tejas which allows the pilot to eject safely.


I have already mentioned the various radars to be seen in the various iterations of the Tejas, so I shall not be discussing it further here.


Image source: Guarding India

The Tejas Mk 1 uses a DRDO developed indigenous EW warfare suit known as Mayavi. It makes use of a digital radar warning receiver, a self-protection jammer and chaff dispensers. Not much information for the same is available, however, it is thought to be a derivative of the D-29 system developed for the Mig 29 UPG upgrade. It also is speculated to use the superlative Elta EL/L 8222WB wide band advanced SPJ pod already equipped on Su-30MKI fleet of IAF. The Mk1A will house the Unified Electronic Warfare suite (UEWS). It has been developed by DARE. It comprises of Electronic Countermeasures (ECM) - Electronic counter-countermeasure (ECCM) capabilities, emitter detection and geo location function, Digital radio frequency memory (DRFM) based jamming and deception capabilities and a wide band RWR with 360 degree threat detection capabilities. It too will carry the ELTA self-protection jammer, which soon will be replaced by an indigenous SPJ being developed by DARE. The identification friend or foe (IFF) system on Tejas is developed by Centre for Airborne Systems (CABS). The Tejas Mark 1A will have indigenous Software-defined radio based tactical data link for secured communication and network-centric warfare capabilities supported by IAF's AFNet digital information grid. Also, IAF has started integration of it’s BNET (Israeli Software Defined Radar {SDR}) with all its aircraft for secure jam-proof voice and data communications between its air, ground and space assets for network centric warfare. A small issue which may arise in the future is the Indian Navy uses DRDO developed SDR for its asset, and at the same time Indian Army is yet to select it’s SDR, this may create issues in interoperability between the three services, which hopefully will be solved by our engineers, so that assets of the 3 services seamlessly communicate.


The Tejas Mk1 and 1A have an offset pylon on their belly to carry a portable podded sensors like electro optical/infrared (EO/IR) sensor pod, forward looking infrared (FLIR) - laser designator pod and ECM pod. A podded EO/IR pod will offset the disadvantage of the Tejas where it does not have an inbuilt sensor. However the Mk2 will have a DRDO designed EO/IR sensor. Currently the Tejas will use the Israeli Litening 3 pod, which is also used by other aircraft of the IAF like the Su-30MKI and the Mirage 2000, it too shall be replaced by an indigenous pod. Tejas uses various form of onboard navigation instruments like tactical air navigation (TACAN) system, terrain referenced navigation system (TERPROM), VHF omnidirectional range–instrument landing system (VOR–ILS), DARE developed enhanced ground proximity warning system (EGPWS) and ring laser gyroscope based inertial navigation system integrated with satellite guidance from Research Centre Imarat (RCI).



A closer look at the TR units of the Uttam flight controls




A mock up of the Uttam AESA Radar Mounted on the nose cone of Tejas

[DrPriyankT]

Flight Controls
The Tejas has been designed with an inherently unstable airframe to give it added agility, hence to keep the Tejas controlled inflight, it needs multiple adjustments to it’s flight surfaces. is equipped with Aeronautical Development Establishment developed full authority quadruplex fly-by-wire digital automatic flight control system with fail-operational/fail-safe safety feature for automatic manoeuvre limiting and to ease pilot handling. The Tejas flight control system is operated with dual redundant modular MIL-STD-1553B standard databus and open architecture Digital Flight Control Computer developed by DARE. The mission computer of Tejas is developed by Solid State Physics Laboratory. Its flight control surfaces are controlled by hybrid electro-hydraulic actuators through the digital flight control computer. The wing's outer leading edge incorporates three-section slats which allow to operate at a higher angle of attack, while the inboard sections have additional slats to generate vortex lift over the inner wing and high-energy air-flow along the tail fin to enhance high-AoA stability and prevent departure from controlled flight. The wing trailing edge is occupied by two-segment elevons to provide pitch and roll control. The only empennage-mounted control surfaces are the single-piece rudder and two airbrakes located in the upper rear part of the fuselage, one each on either side of the fin.

A closer look at that shape and flight surfaces of a pair of Tejas's


Another look at its aerodynamic shape



Weapon’s Package
The maximum payload capability of Tejas is 5,300 kg (11,684 lb). All weapons are carried on one or more of seven hardpoints with total capacity of greater than 5,000 kg: three stations under each wing and one on the under-fuselage centreline. Tejas also incorporates multidispenser racks which allow it to carry multiple weapons on the same rack, enabling it to carry more weapons on the same number of hard points. An eighth offset station beneath the port-side intake trunk can carry a variety of pods like FLIR, IRST, laser rangefinder/designator, as can the centre line under-fuselage station and inboard pairs of wing stations. Auxiliary fuel tanks of 725, 800 and 1,200 litres can be carried on three wet hardpoints under the fuselage and wing to extend range. An aerial refuelling probe on the starboard side of the forward fuselage can extend range and endurance.


The gun carried on board the Tejas is a 1x 23 mm twin-barrel GSh-23 cannon. It operates on the Gast Principle. It requires no external power source. It is a twin-barreled weapon in which the firing action of one barrel operates the mechanism of the other. It provides a much faster rate of fire for lower mechanical wear than a single-barrel weapon. This cannon is mounted on the belly of the Tejas.


Its chief close combat missile’s will be the Russian R-73 Infrared Homing missile, and after multiple rounds of testing (due to wind flutter issues, as the Python 5 has 18 control surfaces), the Israeli Python-5 missile. Both these missiles are off-boresight missiles, which means the missiles can track targets many degrees of the centreline of the aircraft. Both have cryogenically cooled image homing infrared seekers. Both have a claimed range of around 30-40 km’s. Python 5 has the unique ability of lock on after launch and its off boresight ability is so high that it can actually target aircraft behind the launch aircraft. Both these missiles can be coupled to the pilot’s helmet mounted display to give the pilot the ability to lock on to targets with these high off boresight missiles, giving them a deadly advantage in dogfights. The Tejas with it’s small size, high agility and deadly close combat missiles can make it one hell of a dogfighter, making it the spiritual successor to both the Gnat and the Mig-21. In the future, it is expected to be integrated with the superlative ASRAAM missile and the IR variant of the Astra Missile. For those who don’t know, the ASRAAM has been selected to the CCM missile for the Jaguar DARIN 3 and it has already been test fired from the Su-30 MKI.


Currently it’s BVR missile is the Derby Missile. It is an Israeli BVR missile with a range of about 50 Km (claimed), and many reports also claim that the I-Derby ER with a claimed range of 100 km have been integrated as the BVR missiles for both IOC and FOC Mk1 Tejas. It too is a highly capable missile derived from the Python series of missiles. It is an active radar guided missile. An interesting fact about the Derby is that they were originally purchased for the Indian Navy when they were upgrading their Sea Harrier’s in 2006. The British had then denied us use of their Blue Vixen radar which would have given them the ability to fire BVR AMRAAM’s, so we took the help of the Israeli’s who upgraded the Harriers with the Elta EL/M-2032 radar and the Rafael 'Derby' medium-range air-to-air BVR missile. They were in service till 2016. In the very near future, the Tejas will be integrated with the desi Astra Mk1 with a claimed range of 110-120 km. Trials of the Astra Mk1 with the Tejas were to begin in H1 2021, but no report for the same is available. It will be integrated in the future with the 160 km Astra Mk 2 and the 350 Km range Astra Mk. 3 based on Solid Fuel Ducted Ramjet (SFDR) engine is being jointly developed by India and Russia. There is also a plan to integrate it with the Russian R-77 as we have ample stocks of the missile.


For its ground attack role, it will be equipped with the Russian Kh-59 missile, which has range of 100km plus and a warhead of 320kg. Whenever the lightweight Bramhos NG gets developed, it with all variants of the Tejas. For it’s SEAD (Suppression and Destruction of Enemy Air Defence) role, it shall be equipped with the Rudram Missile. For its antiship role, it shall be equipped with the Kh-35 missile. It will be equipped with the High Speed Low Drag (HSLD) bombs developed by DRDO in the 250-500 kg category. It will be equipped with the indigenous DRDO Glide bombs for precsion long range attack, they are like the Hammer bombs which equip the Rafale. Israeli Spice bombs are also equipped with it. For anti-runway role, it is equipped with SAAW, again developed by DRDO. In Laser guided bombs, it can be equipped with DRDO Sudarshan Bombs, Griffin Bombs (Israeli), Paweway Bombs (American) and KAB-1500L (Russian). Amongst unguided bombs, it will carry the FAB-500 and OFAB series of bombs. In IAF’s Ironfist and Vayu Shakti exercises, it has won accolades for its’s precision when it comes to bombing targets.

On the outboard pylons - two R73CCM's
On the middle pylons - a pair of fuel tanks
On the offset centreline pylons - a lightening pod



Completing winter trials in Leh in 2008. Contrary to what naysayers said! Complete with two missiles, targeting pod and two fuel tanks. Spituk monastery in the background



Firing the Python-5 missile as part of weapons trials



Dropping what looks like a General Purpose High Speed Low Drag (HSLD) bomb as part of weapons trials.

[DrPriyankT]

Variants of the Tejas

Tejas Mark 1 − Single-seat operational variant for the Indian Air Force. 16 aircraft are delivered in IOC standard constituting No. 45 Squadron IAF and delivery of Tejas Mark 1 in FOC standard has begun and 18 Squadron (Flying Bullets) has been raised with the first aircraft in May 2020. The delivery of the remaining 15 has been delayed due to COVID-19. FOC standard Tejas Mark 1 are BVRAAM capable, with general flight envelope expansion, increased angle of attack, higher g-limit of +9 g, updated avionics and flight control software suite as well as capable of hot refuelling and Aerial refuelling. Also, FOC aircraft have easier to remove panels to speed up field maintenance. IAF will have 40 single seat MK1 aircraft and 10 twin seat trainers.


Mk1A- It will be manufactured in single and twin seat variants. It will have AESA radars, a digital radar warning receiver, and the ability to mount a self-protection jammer right from the time of roll out. It is an increment on the Mk1. It will replace the Mig-21 Bisons. ( I personally can't wait for it to replace them, specially considering the fact that we lost 4 Bison's this year.)


MK2 A.K.A Medium Weight Fighter. It will replace the non-upgraded Jaguars, and in the long term Mig 29’s and Mirage 2K’s, so it has big shoes to fill. It is a 17.5 tonne class fighter with close coupled canards and integrated IRST system. Metal cutting for the same has commenced in February 2021, with rollout expected in 2022, and first flight in 2023. It will have a weapon carrying capacity of 6.5 tonnes, it will use a DRDO Uttam AESA Radar, with a unified electronic warfare system, an integrated IR/EO sensor and it will also be equipped with a dual colour missile approach warning system. It will incorporate sensor fusion to provide the pilot with a unified picture of the battle space around him, and to reduce the pilot’s burden, all data will be displayed on a single widescreen display in the cockpit, and the pilot will have a joystick which will be mounted on the right side and throttle on the left to increase cockpit space. Due to it’s increased weight and power requirements, it shall be powered by a GE F414-GE-INS6 engine.


SPORT - Supersonic Omni-Role Trainer (SPORT) aircraft is a two-seater Lead-in Fighter Training [LiFT] aircraft being developed from LCA Trainer Mark 1 for export purposes as light fighter.


CATS MAX - The main component of HAL Combat Air Teaming System (CATS), CATS MAX will be a twin seater Tejas Mark 1A modified with CATS interface to act as the mothership of CATS components. The CATS MAX is to be crewed by a pilot and a weapon system officer (WSO, pronounced "wizzo"), with the later controlling the CATS. We shall discuss CATS in a later post

[DrPriyankT]

Tejas and its Significance to the IAF


As mentioned earlier the Tejas was designed ground up as a piece for piece Mig 21 replacement, even though its design has an obvious inspiration from the Mirage 2000! So how it fit into the IAF scheme of things? The Tejas is to replace the Mig 21 as a point defence interceptor for the IAF at forward airbases like Uttarlai, Phalodi, Suratgarh, Naliya, Pathankot, Hasimara, Tezpur and Chabua. It will be perfect low cost aircraft to perform routine interceptions when the aircraft is on operational readiness alert. It will make sense to send out Tejas on these sort of missions as it spools up faster than twin engine fighters, so it can be up and away easily, and a second equally important reason is that its much cheaper to send light single engine fighters for bread and butter interceptions as compared to heavier fighters. As an example, Japan is finding it increasingly expensive to send their F-15J fighters for intercepting rogue PLAAF fighters conducting their airspace intrusions. Frequent scrambling of these fighters leads to loss of precious airframe and engine hours for each aircraft, whilst increasing maintenance costs when the planes get older. Taiwan also faces the same issues with their F-16’s and Mirage 2K’s. Hence basing Tejas at frontline fighter bases will free up heavier fighters like the Su-30MKI’s and Mig 29’s which are currently based at frontline bases like Bhuj, Jamnagar, Halwara, Adampur, Jodhpur, Tezpur, Chabua and Hisar, and at the same time save on costs which are otherwise incurred from frequent scrambles of heavier jets, saving precious cash which can be used for other capital intensive acquisitions. Also, the frontlines bases were designed with hardened aircraft shelters which were originally designed to fit the Mig 21’s due to their sheer numbers. The wingspan of the Mig 21 is around 24 feet and its height is around 14 feet, whereas wingspan for the is around 27 feet and its height is around 15 feet. Hence the hardened aircraft shelters constructed around the dimensions of the Mig 21 will accommodate the Tejas with almost no difficulty, saving again on costs which would have been incurred had we had to rebuild shelters around the dimensions of a Su-30 MKI or a Mig 29.


The Tejas is an all-round multirole fighter which can perform air to ground and air to air missions with equal elan, something the Mig 21 cannot (it can carry only unguided bombs and rockets). It’s small size and carbon composite construction enables it to stay relatively unseen on radar and even visually until its too late. Its like how Wing Commander Abhinanadan suddenly jumped up on to the unsuspecting Pakistani’s in his tiny Mig 21. The Tejas can take it a step further. In the valleys of Ladakh or the Northeast, it can spring a nasty surprise on the adversaries, when it suddenly emerges from the valley floor below radar clutter, to intercept enemy fighters. This ability gives the Tejas the ability to stealthily take out enemy air defence nodes, especially in hilly areas.


People have criticised the Tejas for its low internal fuel capacity. I personally cannot get their criticism. Tejas has been designed as point defence interceptor with multirole abilities which is to be based at airbases close to the border, to take off quickly when the klaxon goes off to intercept suspicious aircraft, not as a long range interdictor. It has three drop tanks and inflight refuelling to give it a boost in range. With its current range and air to air refuelling abilities, it can easily conduct Combat Air Patrols in border areas, and conduct strike missions into enemy territories.


One may wonder why then its based in the south at Sulur Airforce Station. The squadrons based there (SQ 18 and 45) are currently tasked with operationalizing the aircraft into the IAF, to help it understand the aircrafts strengths and weaknesses, far away from the prying eyes of the PAF and PLAAF. Here the IAF is developing tactics specific to it, and how it can work with the other fighters and aircraft in our arsenal. Remember, the Su-30 was first based at Pune, where they were put to their paces before being deployed in numbers elsewhere.


The biggest gamechanger for the Tejas is, that it has spurred the development of hundreds of MSME’s in India to develop world class defence products and has given us confidence to develop newer aircraft and technologies. The Tejas may very well be a steppingstone to developing India into an aerospace powerhouse. We have the talents and brains to embark on such endeavours, we just need the right policies to push them to their logical conclusion.

Disclaimer: No sensitive information has been divulged in this write-up and all information shared is from public domain.

[saikarthik]

A great consolidation of technology and project facts. Few pictures about technology will make new people to understand them easy.

I couldn't find the sensor suite and protection systems images but adding a couple of images,

Integrated flight control system



Some actuators

[V.Narayan]

Congratulations @DrPryankT for this excellent article full of facts and data. It is hard to find the full story in one place on the internet but now here we have it. Thank you for all your effort in putting it together.

I have been following this project since the mid-1980s when it first came in the news. We now have a fairly competent light fighter and it behooves the IAF to work more closely with HAL-DRDO combine to perfect it. The IAF top brass sadly have not yet fully assimilated that the user be it the RAF or USAF or PLAAF has to work closely with the OEM-Designer to perfect the last mile of a super complex machine like a combat fighter and that last mile is a very long one. The IAF dominated by the flying branch and with inadequate heft of the engineering community has always been used to receiving perfected products (imports or license built). So this is a new new culture that fortunately is now being driven in by the current top brass and insistence of the late Raksha Mantri Manohar Parrikar. Good for them.

Every frontline aircraft does not need to be a Su-30MKI or a Rafale. Just like a cricket team doesn't need 11 Sachin Tendulkar's. To ensure any Air Force has adequate numbers to fight a sustained war we need a mix of big & small, hi and lo and that's where the LCA is the right choice. This aircraft has the potential to be improved incrementally by us for 20 to 25 years. And because it is ours and less expensive than the Rafale it can be built in larger numbers as it should be to recoup the costs and get economies of scale.

The whole saga has had its positive and negative points. First, the negative points of the story (not the aircraft) which were mainly in the 1980s to 2010 where the IAF and MoD set sky high expectations with no thought to national competency in a field or even the ability to develop a given competency. Metaphorically they took a Jane's All Worlds Aircraft book and looked at the latest Western fighters of the time and drew up a specification list. I recall one Air Marshal stating in the press (1980s sometime) that we are only interested in a perfect fully functioning machine with no lead-in time extending for years and if HAL-DRDO can't do that we'd rather buy from MiG or Dassault. I have put in my own words what I remember. Actually his quote was deeply acerbic and dismissive about expecting IAF involvement & support to develop the machine. Sadly that was the attitude that pervaded till the 2000-2010 decade. This is in total contrast to how other big aeronautical nations developed their aeronautical design & manufacture expertise as a national endeavour. China on the other hand always went step by step, did not ask for only the most perfect most well equipped fighters and see where they are now. Our good old Indian Navy did what China's PLA AF did and see where they are now on indigenous design competence.

But now thanks to more enlightened IAF top brass and a whole new generation of designers and management we really do have a competent asset.

My very best wishes to the brave IAF pilots who will fly this beautiful machine and the engineers and technicians who will maintain it and arm it over the many years ahead. Marcel Dassault once said if it looks right it will fly right. And the Tejas definitely looks right to by aviation eyes.

Jai Hind


Photos below from Wikipedia, HAL and the Govt site for the LCA. Note the cockpit, the weapons configurations (some of many) and the manufacturing network

[roadrunner_nv]

Brilliant article! The LCA has long been an aspirational project for our country. To see it in action is immensely joyful. Im sure the AMCA program will incorporate many learnings from the LCA program. A large number of young minds continue to be involved in innovating this space.
My only wish is if we can fly our own aircraft with our own engines (what else would a Team-Bhpian think about?). The Kaveri was a program riddled with blockages but if there was any intellectual superpower that could pull off this feat, it is India. I just hope that there is some work going on behind the scenes that’s addressing this aspect.

[AirbusCapt]

Originally Posted by roadrunner_nv

Brilliant article! The LCA has long been an aspirational project for our country. To see it in action is immensely joyful. Im sure the AMCA program will incorporate many learnings from the LCA program. A large number of young minds continue to be involved in innovating this space.
My only wish is if we can fly our own aircraft with our own engines (what else would a Team-Bhpian think about?). The Kaveri was a program riddled with blockages but if there was any intellectual superpower that could pull off this feat, it is India. I just hope that there is some work going on behind the scenes that’s addressing this aspect.

That's being handled by Safran (France) who has promised to help get the Kaveri engine upto standards. This is an offset of the Rafale program which will help India become self sufficient.

[fhdowntheline]

Great article with a lot of technical depth to salivate the tastebuds of aviation fans like me!.

Only one point that I would like to ask- how relevant would be the need for a Tejas to be able to reach speeds above Mach 1.6 (I understand that's the current limit) ?

Fighters in the similar size/role have slightly higher speeds, for example F16 can do M2.0, the Gripen can reach M2.0, I guess the Mig-21 itself is even slightly faster than that, even a F104 was faster.

Does this put any kind of disadvantage whatsoever on the Tejas on a comparative basis ?

[saikarthik]

Originally Posted by fhdowntheline

Fighters in the similar size/role have slightly higher speeds, for example F16 can do M2.0, the Gripen can reach M2.0, I guess the Mig-21 itself is even slightly faster than that, even a F104 was faster.

I am not an expert in these matters, but a fan of defense technology. With my limited knowledge, the wars of today is fought with who can detect enemy first and with BVR missiles. Tejas was replacement for the interceptor MIG 21 BISON, and it's use is still the same though it can do light multirole too.

It's important to have speed for interception and getting out of range from enemy defense once you have attacked, but I don't think it matters more now considering our operational geography (can do terrain hugging in valleys of the norther mountains) and still emerge as a surprise and again get out. In western border, it's a different case. I will let experts to comment on it.

[RedTerrano]

First of all felicitations are a must for all those involved (I mean technicians, designers, scientists, defence experts et al, not including the policy makers)

Envisaged in the 80's it took decades to enter service. How does this fare with other countries?
Secondly, how does the existing Tejas tech fare with contemporary aircraft? Is that decades behind as well?
Where do we go from here? What stage will we stop becoming a weapons importer and transit to an exporter?

It would be nice if some experts shed light on this.

[nasirkaka]

Feeling nostalgic..

We designed the Ground Support Equipment for the Tejas in 2001 (called LCA in those days). Was fun working with ADA and spending time at HAL hanger hanging around the aircraft, PV1 & PV2.
Thanks for putting this together. Will have to go through this in detail when time permits.

[Raghu M]

I have to say, wonderful article with very good detail to features and specs. I follow military news very closely, so I jumped at this thread as soon as I read the heading. I think the Tejas is one of the best looking fighter jets out there. It's not impressive that it took so long for it to get to test trials. Sad to say but the Chinese recognized the fact that air superiority is priceless and acted swiftly. Alas we could not match their speed and swiftness in achieving manufacturing capacity of the Tejas as they have done with the J-10 jets. The Tejas is capable of even being exported to various countries, it's just that we need to manage the lobbying and the orders in quick time and deliver.