HAL Tejas | Updates, News & Discussions-[Thread 2]

[skynet]

 

[Major Shaitan Singh]

The Indian Navy funds 40% of the LCA-N fighter programme, and intends to purchase at least 46 LCA Navy Mk.2s, the more powerful and capable proposition based on the current Mk.1 platforms in flight test. Much more is known now about what the Mk.2 will really involve. But first a short dash back 12 years.

The LCA Navy programme was sanctioned in 2003. The Aeronautical Development Agency (ADA), which had been entrusted with converting the standard air force variant, imagined it would take six-seven years to convert the platform into a naval prototype. Amazingly, the team at the time officially noted that the changes to the aircraft would be restricted to 15%. As we now know, things turned out quite differently.

A Team LCA-N official explains, "The major constraint of design space due to the existing LCA AF platform resulted in a sub-optimal design and compromises leading to the LCA Navy Mk-1 Variant being heavier than anticipated."

Six years into the project, it was officially noted by the ADA after months of discussions with the Indian Navy, that the LCA Navy Mk.1 wouldn't meet all the customer's capability requirements. These 'shortfalls' were put down to the platform's 'sub-optimal design'. It became imperative that a significantly more powerful and capable Mk.2 of the LCA Navy would be the platform that the Indian Navy would spend its real procurement rupees on.

In 2011, the ADA displayed models of its proposed Mk.2 for the IAF and Indian Navy. Apart from a brief wishlist of performance enhancements, not very much was clear. And to be fair, the team itself was awaiting greater clarity at the time.

Officially, according to Team LCA-N, "This programme (the LCA Navy Mk.2) is envisaged to minimize the constraints of LCA Navy Mk-1 and would have significant changes in design to improve aerodynamics, landing gear & arrester hook optimization, structural design optimization, updated sensors, avionics and flight control system. The landing gear mass of the LCA-Navy Mk.2 aircraft is likely to be reduced by 200-250 kg, albeit being capable of a higher take-off mass."


INTERFACE OF THE UTTAM RADAR & LCA Mk,2
Mk.1 prototypes NP1 and NP2 are now firmly in flight test. Apart from the number of seats in their cockpits, there are other differences: the NP2 naval fighter prototype flies with a modified Israeli Elta EL/M-2023 multimode radar (MMR). Sources add, "In terms of aircraft performance the two Mk.1 prototypes are similar. In that sense, both the prototypes will contribute equally for the carrier compatibility tests from the SBTF. The focus on sensor and weapon capability demonstration will be on NP2."

The Mk.2 aims to sport the in-development L-273/Uttam (the project name, incidentally,revealed first on Livefist) active array fire control radar being put together by the DRDO's Electronics & Radar Development Establishment (LRDE). According to official literature, the radar, intended to also be retrofitted on the Mk.1 aircraft that enter service, modes include air-to-air multi-target detection and tracking, multi target air-to-air combat mode, high resolution raid assessment, high Resolution air-to-ground mapping (SAR mode), air to ground ranging, real beam mapping, doppler beam sharpening, ground moving target indication and tracking and terrain avoidance. In air-to-sea mode, sea search and multi target tracking, range signature and inverse synthetic aperture radar will apply. But that's just the radar.

The the No.5 prototype NP5 will be a Mk.1 twin-seat trainer prototype, the construction of which has already begin at HAL. The NP5 was proposed to save time and as a risk mitigation exercise using existing resources and funds.

The MoD is now all set to clear the third and fourth prototypes, NP3 & NP4, both to be single-seat fighter prototypes of the LCA Navy Mk.2, incorporating all airframe and platform changes, including aft fuselage changes to house the new, larger and more powerful General Electric F414-GE-INS6 turbofan engine. Team LCA-N sources confirm that there will be changes in most sections of the airframe.


The Indian Navy funds 40% of the LCA-N fighter programme, and intends to purchase at least 46 LCA Navy Mk.2s, the more powerful and capable proposition based on the current Mk.1 platforms in flight test. Much more is known now about what the Mk.2 will really involve. But first a short dash back 12 years.

The LCA Navy programme was sanctioned in 2003. The Aeronautical Development Agency (ADA), which had been entrusted with converting the standard air force variant, imagined it would take six-seven years to convert the platform into a naval prototype. Amazingly, the team at the time officially noted that the changes to the aircraft would be restricted to 15%. As we now know, things turned out quite differently.

A Team LCA-N official explains, "The major constraint of design space due to the existing LCA AF platform resulted in a sub-optimal design and compromises leading to the LCA Navy Mk-1 Variant being heavier than anticipated."

Six years into the project, it was officially noted by the ADA after months of discussions with the Indian Navy, that the LCA Navy Mk.1 wouldn't meet all the customer's capability requirements. These 'shortfalls' were put down to the platform's 'sub-optimal design'. It became imperative that a significantly more powerful and capable Mk.2 of the LCA Navy would be the platform that the Indian Navy would spend its real procurement rupees on.

In 2011, the ADA displayed models of its proposed Mk.2 for the IAF and Indian Navy. Apart from a brief wishlist of performance enhancements, not very much was clear. And to be fair, the team itself was awaiting greater clarity at the time.

Officially, according to Team LCA-N, "This programme (the LCA Navy Mk.2) is envisaged to minimize the constraints of LCA Navy Mk-1 and would have significant changes in design to improve aerodynamics, landing gear & arrester hook optimization, structural design optimization, updated sensors, avionics and flight control system. The landing gear mass of the LCA-Navy Mk.2 aircraft is likely to be reduced by 200-250 kg, albeit being capable of a higher take-off mass."


INTERFACE OF THE UTTAM RADAR & LCA Mk,2
Mk.1 prototypes NP1 and NP2 are now firmly in flight test. Apart from the number of seats in their cockpits, there are other differences: the NP2 naval fighter prototype flies with a modified Israeli Elta EL/M-2023 multimode radar (MMR). Sources add, "In terms of aircraft performance the two Mk.1 prototypes are similar. In that sense, both the prototypes will contribute equally for the carrier compatibility tests from the SBTF. The focus on sensor and weapon capability demonstration will be on NP2."

The Mk.2 aims to sport the in-development L-273/Uttam (the project name, incidentally,revealed first on Livefist) active array fire control radar being put together by the DRDO's Electronics & Radar Development Establishment (LRDE). According to official literature, the radar, intended to also be retrofitted on the Mk.1 aircraft that enter service, modes include air-to-air multi-target detection and tracking, multi target air-to-air combat mode, high resolution raid assessment, high Resolution air-to-ground mapping (SAR mode), air to ground ranging, real beam mapping, doppler beam sharpening, ground moving target indication and tracking and terrain avoidance. In air-to-sea mode, sea search and multi target tracking, range signature and inverse synthetic aperture radar will apply. But that's just the radar.

The the No.5 prototype NP5 will be a Mk.1 twin-seat trainer prototype, the construction of which has already begin at HAL. The NP5 was proposed to save time and as a risk mitigation exercise using existing resources and funds.

The MoD is now all set to clear the third and fourth prototypes, NP3 & NP4, both to be single-seat fighter prototypes of the LCA Navy Mk.2, incorporating all airframe and platform changes, including aft fuselage changes to house the new, larger and more powerful General Electric F414-GE-INS6 turbofan engine. Team LCA-N sources confirm that there will be changes in most sections of the airframe.

 

[vsdave2302]

We really need some information on MK 2

I am more interested in discussion of LCA MK1 performance improvement. I foresee 2 main shortfalls. Highest speed and STR. If tejas can hit Mach 1.8 and can achieve 18* STR, this plane should be a very good one. The reason identified are dragy large wing and intake design problem. We should work on this 2 areas to resolve these problems and make MK1 more acceptable. If we can resolve these 2 issues than same modifications shall go into Mk2 also and improve the performance also.

 

[Stephen Cohen]

I am more interested in discussion of LCA MK1 performance improvement. I foresee 2 main shortfalls. Highest speed and STR. If tejas can hit Mach 1.8 and can achieve 18* STR, this plane should be a very good one. The reason identified are dragy large wing and intake design problem. We should work on this 2 areas to resolve these problems and make MK1 more acceptable. If we can resolve these 2 issues than same modifications shall go into Mk2 also and improve the performance also.

Saurav Jha's Blog : The Radiance of Tejas: A bright prospect for 'Make in India'

The Mk-II design will specifically address the sustained turn rate (STR), climb rate and transonic acceleration shortfalls of the Mk-I. The ASR requires a STR of 18 degrees (same as the F-16's) and Mk-II will close in on that. The climb rate will also be more or less satisfactorily reached. Transonic acceleration is expected to be realized fully. Moreover the Mk-II airframe will certainly be able to reach and fly through Mach 1.8 in a dive.

 

[vsdave2302]

Tuesday, February 10, 2015

The LCA Navy NP1's carrier compatibility test off the ski-jump in Goa last month yielded masses of valuable data for a team that hasn't been able to put the aircraft into the air even a fraction of the number of times it would have liked to by now. But while there was plenty to be at least somewhat cheered about, there were two major areas that the flight drew attention to. Two areas the team is focusing on fixing with all its resources:



1. The Control Law and Flight Control System (FCS) Software needs additional coding and updating to handle the higher performance of the platform. "This will enable extracting the best performance of the aircraft in a safe manner as the margins are progressively reduced," say sources on the team.

2. The second take-away was mechanical, and just as crucial: the NP1's nose landing gear extension routine was faster than predicted or expected. Sources on the team confirm that, "Minor modifications to the nose landing gear are in progress and would be available on the aircraft by end Jan 15."

3. Another lesson learned, according to team sources, is that design teams will need to be "even more pragmatic in keeping margins as excess reserves get compounded and could lead to load exceedence."

4. The team is also considering excessive airspeed to be something to look out for. "While on first appearances, excessive airspeed appears to be harmless, it could aggravate aircraft control problems if flight control failures are encountered," team sources said.
Once the 2 tangible fixes are complete, and operating procedures on the other two are in place, the scene shifts back to Goa in March for more ski jump flights, where the flight test team will work towards reducing margins to arrive at final performance levels -- the first final, or close to final operating parameters of the LCA Navy. "Also, it is planned to initiate activities towards arrested recovery starting with dummy approaches on the landing area, ‘taxi-in’ arrester hook engagements on to the arrester wire at the SBTF and final flight engagement," say team sources.

Questions have been raised over whether 'surprise' angle of attack and climb performance actually demonstrated problems with simulation studies, team sources said, "Extensive simulations had been made to predict landing gear loads and the behaviour of all other systems during the ski jump launch. The aircraft was extensively instrumented to enable validation of simulation. The landing gear loads and other system behaviour obtained from the actual ski jump launch were close to prediction."

Series concludes tomorrow with Part 3: The LCA Navy Mk.2

LIVEFIST: PART 2: The Four 'Fixes' After LCA Navy's Ski-Jump Flight

@sancho,

All predictions must have been made on basis of Airforce tejas performance. Does this mean that There is some change in Naval MK2 which enhansed the performance of Naval MK2. Whether the same changes if made in Airforce Tejas shall improve its performance as well?

Dose this mean that it will fly faster or carry higher load or shall have higher STR etc? (Since the lift is high?)

Saurav Jha's Blog : The Radiance of Tejas: A bright prospect for 'Make in India'

The Mk-II design will specifically address the sustained turn rate (STR), climb rate and transonic acceleration shortfalls of the Mk-I. The ASR requires a STR of 18 degrees (same as the F-16's) and Mk-II will close in on that. The climb rate will also be more or less satisfactorily reached. Transonic acceleration is expected to be realized fully. Moreover the Mk-II airframe will certainly be able to reach and fly through Mach 1.8 in a dive.

Yes I know that. But it is in dive mode. i want that performance in normal flight. Plabnes like MKI, Mirage do Mach 2+ in normal flight. Mk2 shall have more powerful engine compare to mirage so it should do Mach 2+ also. Why it will have Mach 1.8 and that too in dive. That is why I say that we need to work on aerodynamics and engine integration and air intake.

 

[sancho]

I am more interested in discussion of LCA MK1 performance improvement. I foresee 2 main shortfalls. Highest speed and STR. If tejas can hit Mach 1.8 and can achieve 18* STR, this plane should be a very good one. The reason identified are dragy large wing and intake design problem. We should work on this 2 areas to resolve these problems and make MK1 more acceptable. If we can resolve these 2 issues than same modifications shall go into Mk2 also and improve the performance also.

That's why the IAF wanted "some" more thrust and initially stated the need for around 90kN, but then the navy came in with their requirements and added many things and now we have to wait for a proper MK2 prototype to see what can be achieved and what not.

@sancho,

All predictions must have been made on basis of Airforce tejas performance. Does this mean that There is some change in Naval MK2 which enhansed the performance of Naval MK2.

The first MK2's will be based on the IAF version, but the MK2 upgrade as such, will mainly include IN's requirements. That's why the airframe needs to be lengthened to include more fuel and most likely why the fuselage will be re-designed to include enough space to include the N-LCA gears, without the hump that we can see on the NP1 and 2, so a more aerodynamic design. These modifications however might be a burden for IAF, since they increase the base weight of the fighter, which counters the higher trust to some extend again. The crucial point will be, how much more fuel can be carried internally, because that decides how many external fuel tanks needs to be carried in each mission. If it's enough to just carry 1 centerline 725l fuel tank, instead of 2 x 1200l tanks at the wings, you will reduce drag to a good extend.

The performance of the N-LCA will be even more tricky to evaluate, since from what we see now, it will be based on the twin seat version which alone adds more weight and drag by design. Add the weight of the navalisations and the higher operational limits of using it from short take off distances and possibly reduced payload can't really make it very capable.

 

[Echo_419]

That's why the IAF wanted "some" more thrust and initially stated the need for around 90kN, but then the navy came in with their requirements and added many things and now we have to wait for a proper MK2 prototype to see what can be achieved and what not.



The first MK2's will be based on the IAF version, but the MK2 upgrade as such, will mainly include IN's requirements. That's why the airframe needs to be lengthened to include more fuel and most likely why the fuselage will be re-designed to include enough space to include the N-LCA gears, without the hump that we can see on the NP1 and 2, so a more aerodynamic design. These modifications however might be a burden for IAF, since they increase the base weight of the fighter, which counters the higher trust to some extend again. The crucial point will be, how much more fuel can be carried internally, because that decides how many external fuel tanks needs to be carried in each mission. If it's enough to just carry 1 centerline 725l fuel tank, instead of 2 x 1200l tanks at the wings, you will reduce drag to a good extend.

The performance of the N-LCA will be even more tricky to evaluate, since from what we see now, it will be based on the twin seat version which alone adds more weight and drag by design. Add the weight of the navalisations and the higher operational limits of using it from short take off distances and possibly reduced payload can't really make it very capable.

Seems like a lot of Challenges lie ahead

 

[sancho]

Seems like a lot of Challenges lie ahead

It is, but only because we made it more difficult than it needed to be. The whole NLCA nonsense had made the MK2 upgrade far more complicated and delayed and all that for nothing else than what we will do with the NP1 and 2 tech demonstrators anyway. It would be a disaster if the MK2 gets so heavy now because of IN's requirements, that the TWR or other performance requirements of IAF still won't be met.

 

[Abingdonboy]

 

[sancho]

Mh

ADA Brochure from Aero India 2011

Changes now seems to be:

- height reduced from 4.6 to 4.4m
- no weight reductions anymore!!! (my guess that the weight might even increase seems to be valid)
- IFR probe? (not sure if they have removed it, since it's now part of the MK1 FOC)
- MMR seems to be AESA now
- interestingly still nothing on IRST, which is quiet disappointing

 

[Agent_47]

@sancho how important is IRST for LCA/IAF ?

 

[sancho]

@sancho how important is IRST for LCA/IAF ?

One of the aims of LCA is to take operational tactics of the Mig 21 to the next level. IAF had shown good performance in operating the Migs in passive modes, with radar guidance provided by MKIs. LCA with even lower RCS, even better EW and passive sensors, next to improving AWACS capabilities of IAF, would then be the logical next step.
I once even showed this with the same aim:

To use off the shelf systems of the Rafale to improve the LCA MK2 (and simplify it's development), for example the Thales FSO system with the IRST and TV channel, as well as the MICA (Maitri) IR. This combo of passive sensor and passive BVR missile, would allow the LCA to be used in passive mode, detect and track targets, visually ID the target at longer range than any comparable systems and then launch the missile before the target even knows that the LCA would be around.

 

[sancho]

Official ADA video for Aero India 2015

 

[commander jain]

@sancho any latest news about "AURA" ???

 

[sancho]

@sancho any latest news about "AURA" ???

No, that's a long shot and much dependent on other developments (Rustom H, engines, stealth design...).