Indian Military Aviation News and Discussion

[Arun_S]

FORCE Nov 2010

‘There Will Be Design Changes in LCA Mk-2 and all Design Changes will Lead to a Weight Penalty’

Air Marshal Philip Rajkumar (retd)



In your opinion what are the shortfalls the LCA could be facing currently because of an underpowered engine?



Lack of engine power leads to lack of performance. The main shortcoming would probably be in manoeuvring flight and the ability to take off with the required load from runways in hot and high conditions. There will be increase in time to climb to height and it won’t accelerate as fast. So the Indian Air Force (IAF) in its wisdom has said that they are not happy with the performance of the LCA with its current engine. One of the points mentioned is that the sustained turn rate has been lower than specified. One must understand that the performance parameters laid down in the Air Staff Requirement (ASR) have been arrived after a lot of debate in Air Headquarters. I don’t understand the argument of reducing the payload to meet performance. The IAF requires a certain level of performance to be delivered for the payload that is being asked for. Engine power is important and having arrived at the conclusion that thrust on the current GE-404 engine is insufficient, it is the GE-F-414 that has been chosen.



Now thrust is proportional to fuel consumption and increased thrust will lead to increased fuel consumption which will have a bearing on mission performance. Having a more powerful engine does not automatically increase performance.



What changes will the choice of a new engine require for the LCA Mk-2?



With regards to the LCA Mk-2 there will be design changes and all design changes will lead to a weight penalty. The outcome of this design exercise that ADA is undertaking on the LCA Mk-2 is yet to be seen. The LCA Mk-2 will have a slighter longer fuselage and may carry more fuel as well. Will the weight go up, will they add more fuel, will the aircraft be able to offer the performance demanded by the IAF with an engine offering more thrust and higher fuel consumption are questions I cannot answer, as these details have not been made public. We could however use this opportunity to lengthen the fuselage, look at the wave drag to improve aerodynamics, put a wider chord on the wings to generate more lift, etc. However, this would then essentially result in a new aircraft but it will be a more capable aircraft and this is a good opportunity to do so. The slightly larger LCA Mk-2 can also include essential operational equipment without which the LCA Mk-2 will not be able to fulfill its operational role. These changes would lead to increase in the All Up Weight (AUW) and result in the LCA Mk-2 being different from Mk-1 by 25 per cent.



By when do you see these changes being completed and the LCA Mk-2 taking to the air with the GE-F414 engine?



I will be extremely happy if the LCA Mk-2 flies by 2015 and all these changes are completed in the next five years. If they are changes in chord of wing and length of fuselage, then the FCS will also need changes. All these would again require flight testing, though not as extensive as that of the LCA Mk-1. This will require a flight test schedule that will take 2 to 2.5 years in my opinion. The LCA Mk-2 would then attain operational capability by 2018 and enter operational service with the IAF by 2020. If we can achieve this, it would be commendable.



Is it also time to review the role of the LCA in IAF, considering it will be operating next to the Su 30 MKI and MMRCA followed by the FGFA?



The LCA will be a frontline fighter capable of protecting itself and carrying out a useful strike role. But its theatre of operations will depend on the threat levels it will face. If we develop the LCA Mk-2 with the necessary Electronic Warfare (EW) and countermeasure dispensing capability, I don’t see why it cannot be used in any theatre of war. Given our geographical size and the need to face two fronts, we still need numbers with the IAF talking about 40 squadrons. The LCA will be the 3rd tier after the Su-30 MKI/FGFA and MMRCA. The IAF says that they will take 40 LCA Mk-1 aircraft and those aircraft are important for the simple reason that it will enable both ADA and HAL to obtain spares consumption data as to how many maintenance hours are required per flying hour. This data can be accumulated by using the LCA Mk-1 over this decade to put product support in place. The hope is that by the time the LCA Mk-2 is ready to enter service; all these problems would have been ironed out. The LCA Mk-1 could also be used to create an Operational Conversion Unit (OCU) if required to feed pilots into the system as the IAF will be inducting large numbers of aircraft over the next two decades. The LCA Mk-1 will serve the IAF extremely well for at least the next three decades.



What needs to be done to improve performance and reduce the weight of the LCA?



The way to go about increasing the LCA’s performance is by reducing its drag and weight including structural weight but this is a long drawn out exercise. The entire aircraft has to be instrumented so we can measure the loads existing in flight and then compare the data with design loads that have been catered for. A particular part of the structure could have been made too strong and another part too weak. So we have to perform a structural optimisation exercise that usually results in reduction in weight. The aerodynamic optimisation will lead to some configuration changes. Unfortunately our aeronautical institutions from the days of the HT-2 have never undertaken the task of measuring the aerodynamic loads during flight and optimising the structure. We did not do it for the ‘Marut’ or the ‘Kiran’. I have always maintained that performing a structural optimisation exercise is the way to go. I am told that it is a time consuming exercise, but we have to start from somewhere. There is no easy way out. You can also reduce weight by looking at the Line Replaceable Units (LCA), Head-Up Displays (HUD), and Mission Computers etc.



Will the selection of the GE-F414 benefit any of the competitors in the MMRCA contract for the IAF?



The aircraft using the GE 414 engine in the MMRCA competition are the F/A 18 Super Hornet and the Gripen. If they factor in this development it will definitely benefit as the cost of acquisition of these aircraft would come down a little bit. Certainly if the GE 414 is made in India it will bring down the cost of that acquisition, maybe by about 10 per cent.



Do you see the Snecma-Kaveri engine entering service in the LCA?



I definitely do not see the Snecma-Kaveri engine powering either the LCA Mk-1 or Mk-2. However LCA Mk-1 will be used as a flying test bed to put the engine through its paces, before it enters service. However we have to develop the Snecma-Kaveri engine because we cannot call ourselves an aeronautical power in any sense of the word unless we have our own engine. As we speak the Kaveri engine is getting ready to fly in Russia which will give us an enormous amount of confidence. After the 100 hour programme we will have a significant amount of data. With the French coming in the Kaveri will now become a reality and it will get test flown on the LCA airframe at some point of time. My estimate is that this will happen sometime between 2015 and 2018, once we sign on the dotted line. That is the engine that the MCA will be designed around and it will power this aircraft.



What needs to be done to ensure that MCA flies with an Indian engine?



The first thing that needs to be done is to complete the 100 hour Flying Test Bed (FTB) programme on the existing Kaveri engine. That is an essential pre condition. The data generated from the 100 hour FTB programme, will enable us to communicate much better with the French as we would have flown an engine, compared to the static test beds so far. We will also be able to extract more out of the French if this is done. The next is to develop this engine as soon as possible and put this in a flying test bed and keep it ready by the time the MCA gets designed. If we get our sums right then we can fly the MCA with an Indian engine between 2020 and 2022. This will also require a large number of designers and currently there is a serious manpower constraint in the design bureaus of HAL, ADA and elsewhere. You just have to look at the number of projects ongoing currently, HAL is now developing the LCH, LUH another helicopter in the 10 tonne class followed by programmes for the LCA, MCA, FGFA, Multirole Transport Aircraft (MTA), Intermediate Jet Trainer (IJT), Hindustan Turboprop Trainer (HTT-40) followed by upgrades for Jaguar, Mig-29, Mirage 2000, etc. All this, requires a large number of designers working concurrently as these programmes are being run side by side.

Received by email comments from friends:

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The thing is AM Rajkumar is not definitive, he says so as much. Which may mean he is no longer involved with the program, unlike what I had originally presumed. Still, given his vast knowledge of the program and contacts, some of his estimates may be correct, but its still a point to keep in mind that the definitive changes in the MK2 have not been released, so the changes he is talking about may/may not occur. From what I can gather so far, most of the heavy duty changes in the Tejas Mk2, will be internal vs external, starting from an AESA radar. The fuselage extension and wing modifications are likely for carrying increased fuel as well, to offset the more powerful (and thirstier) Ge414 engine. Other changes include repositioning some of the avionics and control surfaces, plus the FBW hardware will be modified. Its a pretty good touch up of many aspects of the Tejas, but not a total rework by any means. HAL is already outsourcing substantially, to companies like Quest and several others. The amount is likely to go up in the future.

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My view:



>> Basically, if its a 25% change, we are getting a Gripen NG in all but name. Best we buy Rafale or EF asap, and tie up the MMRCA quick.



That is exactly what I was thinking. the 5.5 tonne dry class LCA is RIP as IAF has now put in more aggressive requirements.



I had a long discussion with a key end user karta dharta, and that talk was enlightening as well as a bit disappointing, in that HAD/ADA is at difference with services in terms of mindset and vision. {dont have time to recount what was discussed. much of that I will keep close to my chest}. IAF will be happy to get it NOW as it is now (all warts and all), and get better contious improvement program (CIP) improved craft over time. Make an engine ourselves and use that as bedrock fro next aircraft.



IMHO bottom line is that LCA that is not in operation service is for all practical purpose a dead horse. All this talk of 2018 or 2025 in first service (not qty) does not score high in my books for both IAF and ADA/HAL.



w.r.t. LCA airframe being overweight, a good 100 - 150 kg can be reduced if India gets its landing gear from outside (instead of making it in home).



As for LCA-mkII, wave drag un-estimation killed LCA's low alt supersonic dream, so improving that is obviously important.



Increasing engine thrust dies not automatically translate into higher fuel requirement since, fuel consumption is a function of pilots thrust demand, and max thrust is not required all teh way from T/O to landing, but only during T/O and few minutes into combat. SFC is almost constant for 50-100% thrust regime.



Higher fuel capacity IMHO has come in because IAF wishes to have an expanded role LCA with longer legs / endurance and not sacrifice aero performance due to external tank (la. conformal tanks)



increasing wing span will make LAC-II fly like LCA-I.



The key piece missing is no talk of Thrust vectoring/



Watch out LCA replacement will come out in the form a similar sized UCAV. Its engine thrust of ~ 5 tonne (la kaveri). No kidding.



TSP getting chini bandar in qty is a problem that needs to fixed quickly by getting LCA's in qty.