The Safran/RR GTRE Collaboration                                          Prof. Prodyut Das

17-10-2025

The proposed collaboration with foreign companies for the development of a 120 kN jet engine is not recommended. The objections are:

1.      We are trying to buy with money what can only be acquired by dedication.

2.      The requirement itself is debatable and it has NOT been debated sufficiently. The designated aircraft’s specifications conform to fashion not task. A task-based specification will not justify super cruise and hence the 120 kN engine.

3.      The proposal for the collaboration comes from people “with interests but without liabilities”. All our failed projects fall into this category.

4.      We are ignoring the Antaeus factor. Each collaboration paves the way for the next.

5.       The lead vendor is unfit for the leadership.

6.      The slow progress of projects ensures that that the knowledge never reaches critical mass for breakthroughs. More knowledge is being lost through retirements than acquired through activity hence the continued stalemate.

7.      The funding can be put to better use.

Without correcting the factors above no effort will be sufficient no promise will be realized.

The text below may be considered as amplifications of the above views. The points need intense free for all Panchayat.

The Defence Ministry is in talks with RR and Safran to collaborate for the development of a 120 kN engine for AMCA. What looks like action is actually a symptom of shooting in panic; Decisions are being taken by people who can be sold the Aeronautical equivalent of the Brooklyn Bridge. Who has originated the idea is not known. The design knowledge of the sanctioning authority is zero. He goes by “advice” given by people with interest in the public funds but who have no liabilities when it gets delayed. The proposal has beneficiaries but not in engine development.

Our failure vis a vis the Chinese lies in the lack of focus and continuity a permanent “Malik” brings. The RM or the Secretary are “tourists”. -the one is a fourth in a span of ten years, the other, also new, comes from a background of Industrial publicity (IINFT). They can only give part time attention to a job where full time attention is needed. It is no accident that there are no relevant State managed aeronautical Industry successful in  a multi -party electoral democracy. One has to have a knowledgeable “Maalik” to vet the proposal, A knowledgeable Maalik (say the equivalent of Baba Kalyani) would not have stopped the development the Kaveri in 2008 or sanctioned the developments of the TAPAS BH or the Tejas Mk1 as proposed. 

The measurable objections to the collaboration are:

1.                 We will learn little. The engine core, which is where the advances are - the low loss combustors, the mixings of fuel and air for smokeless combustion, the combustion stabilization under widely varying flows, the stator and HP turbine blade cooling passages design- and their manufacture, i.e. the ransom technologies, will be with the French. The “collaboration” will be “outside the core” and GTRE will be sucking at the hind tit.

 

2.                 The entire concept of Air Power is under flux. When Western Financial papers take the trouble to downplay Sindoor in a sustained manner it tacitly acknowledges that Op. Sindoor has re-written the rules. Whether we need a 120 KN engine to create a “Western Concept fifth gen” to the urgency that we blow Rs. 65,000 crores on the project is very debatable- we are falling into a trap created by Western marketing. It has not been expertly debated because one of the parties- the developers - lack the soft knowledge and the involvement to understand the customer; the requisite level of trust has not built up, the proponents are “parties with interest but without liabilities”- they want the project at any cost because the funds give a sense of importance yet they are totally insulated from the outcomes.

 

3.                 We can wait. The AMCA is probably past its time and certainly meet the fate of prolonged development , a technique perfected by ADA. There will be NO change in that.  No wisdom there be in jumping early to catch the 6^th generation trapeze which is too far away. A good 4++gen will do e.g. Tejas if weight is reduced and the thing re- engineered for common sense. The Tejas’ history arouse misgivings that truth is being suppressed. If at all, a 43 yrs old project needs a replacement, not PR.

4.                 Every licence production of the past was a collaboration. Why did we fail and the Chinese, who hauled themselves up by their boot straps, succeed? Without re-organizing, we shall fail again.

 

5.                 Some glaring reason we fail is because:

 

a)      We are continuing to keep the private sector- the big ones, with muscles to do the moving- at arm’s length, the Labs preferring the smaller ones which the Labs can control. Those who ask for China funds for their labs do not ask for China levels of justice, participation and fair play.

b)     The glacial progress ensures rate of knowledge generation is lower than the rate of knowledge wastage. A five-year project taking fifteen years means that very little of the “officer” material accumulates. The Leaders retire, the Wheedler is retained.

c)      The “metaphysical” objection to this collaboration is we are trying to buy, with money, what can be only acquired through taciturn action by iron willed men.

A weakness in soft knowledge- a disdain for history

The Kaveri failures were garden or common failures. Engines will fail during development. Denigrators of the importance of old wives’ tales will have missed the tale of the development of the RR Avon. The Avon, then known as AJ 65, was a tremendously unruly beast to tame its surging and blade breakage. It was heart breaking but Hooker didn’t go to a consultant; Being an engineer he persisted. Old wives in the game will know he changed the Avon’s power turbine design from a single to two stages-thus reducing blade stress and therefore breakage which is easy to understand but it also reduced the engine weight- work that one out. Many non-engineering qualities are required to develop an engineering product or you use enormous quantities of (unavailable) technology to solve common sense problems, no amount of unctuous “babu giri” can get you past the laws of basic science. Ask for collaboration and a fool will be parted of his money and, that too, like this case, on the door step of success; this collaboration is just that. There are things a collaboration cannot buy. If the GTRE feels that it can’t do the job there are others in the country who can. No collaboration, Try again - but under new Command.

GTRE did not lack funds. It lacked the involvement of the directing staff.

Our past history of collaboration shows we also lack the ability – for reasons not known- to meet as equals with the collaborator. The Tejas is one of many examples. We will waste funds.  Given exchange rates, we shall get perhaps Rs. 6500 crores worth of value – one tenth of what if it was done locally.

Past “rides” we have taken

The Labs and agencies appear not to have the ability to handle collaborations- or there is “sabotage by subtlety” . The results show that. I see a pattern where we start off well enough but at the crucial moment the configuration is changed as if a brilliant designer came in and made subtle changes which guarantee cascading troubles, slow rectification and almost a “monkey on a grease pole” situation. I have no idea how it happens but the pattern is there. I have given some notes at the end which you may please see.

We do not need funds, collaborations or need to accept delays. We, need a serious review of the process of approving the configuration. This is essential because the delay and cost starts here and never ends. The Tejas delays were embedded into the configuration

The configuration-based failures are limited to a clutch of organizations. Many DRDO units (ADA is an independent body outside DRDO) have produced excellent products. The various artillery pieces, INSAS, some of the Radars and sonars were the envy of the West, the missiles are world class and now battle proven as is the Arjun and the Nag. Amongst the PSUs Hal’s Dhruv is unbeatable and GRSE and MDL are respected names. The disappointment with these programmes can be that they have taken 13 years against a possible five or six.

Delay is also unacceptable because  it prevents build-up of critical mass of competence-the rate of accumulation of expertise remains sub functional but those others appear to have “loitered with intent”. The delays were built in. There can be no excuses for Tejas to take 43 years or the TAPAS BH platform having problems meeting fairly basic specifications. As detailed earlier the TAPAS platform performance was being met in the 1930s. The approval for these projects was given in one case by over-ruling informed criticism and in the other -without sufficient soft knowledge that should have seen the problems sticking out like sore thumbs.

To specifications or to task? A case studies.

We think we need a 120 kN engine because everyone else (or so we think) has “super cruise” for our AMCA. The Chinese H 36 is not super cruising. This conclusion does not need high-quality technical scrutiny but common sense. Here we are designing to a matching specification when we should design to a task- in this case – how to counter the limited number of enemy 5^th gen.  What does History tell us?

 In 1940 the Russians (like us!) woke up to the German threat. They commissioned the development of 22 designs -nota bene-22- single seat fighters designs of which three Yakovlev (YaK), Lavochkin, Gudkov, Gorbunov (LaGG) and Mikoyan Gurevich ( MiG) made the grade in terms of performance and timeliness. Their anticipated German opponent was the acme of western technology expertly flown. Yet in designing their fighters the Russians, with Slavic stoicism, went for the task-based rather than the specification matching approach. I will resist temptation  to hobby horse and confine myself here just to one aspect-the airframe’s engineering- and how the Russian approach was profound engineering. (Please see notes at the end for some further tit bits).

By 1939 when the Kremlin met for the new fighter’s conference (note- conference= panchayat), the world standard for fighter airframes was the all-metal light alloy yet none of the Russian fighters were all metal. The Yak-1 was a steel tube, wood and fabric identical in technology to the German Fokker EV or the Albatross D V of 1918, the MiG-1/3 was wooden monocoque aft of the firewall and the LaGG-1/3 was all wood. The brilliance of the “retrograde engineering” was in layers,

1^st.Layer was common sense. Lightweight materials, in this case aluminium, are not justified in small structures. They don’t save weight but add complexity.

The 2^nd layer was the deeper wisdom. Compared to the resources required to produce aircraft quality duralumin, very little is needed to set up a seasoning kiln and sawmill next to a Siberian Forest to get aircraft quality timber sawn to size. The machinery and factories required to build wooden and steel tube 1918 technology airframes were very little and they could operate in Siberia in near open sheds at -40 degrees C. with, very little by way of power supplies. Crushing all German hopes of a fall in Russian aircraft production due to disruptions by the planned invasion - Soviet fighter production actually went up 4 times in the first year.

The 3^rd layer of wisdom in the choice for wood were the people who built the aircraft: welders, glue smiths, joiners and carpenters in peacetime. Though skilled they would have been wasted as cannon fodder in the Infantry since their acquired skill would be of no use in metal aircraft construction. Here their skills were tapped to produce aircraft.

Did the designers think of all this? There are records to indicate that they did. Aircraft design is not all technology. It is a minimum of technology carefully buttressed by common sense, good engineering practise, history, old wives tales and superstitions. In the Fighter Conference – which were surprisingly democratic and outspoken-any fancy proposal would be brutally shot down amidst heavy jeers and sarcasm by the Avianarkomat. The same interlocuters permitted all Russian bombers to be all metal- where it made sense.

What came out in the wash?

The natural question is “okay, the Russians were bloody geniuses but how did the crude designs work against the sophisticated Germans”? History gives the answer. The VVS (Russian Air Force) swamped the Luftwaffe and ground it down. period. The Germans had no chance.

Let us put some numbers on the back of the envelope to estimate the probable outcomes. We assign weightage to the various characteristics relevant to the case being studied- wing, power, span loadings, armaments, fire power range etc and form an equation where

combat potency of the individual aircraft = i ……. (1) Sigma xi summed over n 

n being the number of attributes under consideration and x_i   is the potency of the particular attributes, say fire power. Unfortunately, most comparison of specifications end here and leads to a tendency of matching specification as we have done in the AMCA.

Whilst combat potency of an individual fighter aircraft can be mapped fairly accurately it does not reflect the effect of numbers for which we must modify the above with a n² which is the Lanchester’s law and n is the number of unit involved in the combat so we have

Combat success probability =  x n² …Sigma xi multiplied by n squared…. (2)

Let us compare the outcome of the Air war on the Eastern Front 1941-45.

The Russians produced and fielded 75,000 single engine fighters over the period June 1941 to May 1945.The Germans produced a total of 55,000 fighters over a 6 year period May 1939 to May 1945 which they had to spread over two fronts i,e, as a first approximation an yearly availability of fighters of say 5000 German fighters for the Russian front versus an annual Russian availability of 17,000 fighters.

If you crank in these figures, the approximation is for stalemate to occur i.e.  neither side could dominate over the other the individual Russian fighters would have to be one twelfth as effective.

In reality the Soviet fighters were not at all “inferior” but were really different in approach, which requires maturity to appreciate rather than insecurity to condemn for being different, The Russians were comparable in a peculiarly different way , The net result was the differently concepted Russian Fighters available in vast numbers not only overcame the massacre in the opening phases of Barbarossa or the handicap of the loss of Air Force leadership in Stalinist purges they allowed the Russians the space to learn the tricks and fight back till Berlin. The VVS ground out the Luftwaffe gaining upper hand within a year,

A Note on the “different” engineering of the Soviet Fighters.

Sl. No	Aspect	Comments
1.	Air Frame structure	Modified 1918 technology with small improvements in glues and processes. Comparable to Albatross DIII/ Fokker EV of WW1
2.	Aerodynamics	First rate. The Russian (Polikarpov (?)) penchant for short fuselages gave rise to stability issues but otherwise all Kharasho!
3	Powerplant	A Hispano Suiza 12 Y based approach boosting power from 760kw of the French HS 12Y of  1939 output to 960 kW at the expense of engine life which was reduced to a statistically justifiable number. The engine weighed 900 kgs compared to a DBs 1100 kgs and, by use of standard design practises, made suitable for mass production. Approx 1,36,000 were made in 4 years. The skill in recognizing a sound design to base and then implementing a rational and yet bold redesign is to be noted
4.	Armament	Excellent quality by tradition but weight of fire was half of German fighters. Possible Justification; Tyro pilots- Russki or Niemets- open fire from too far and waste ammo. anyway, but the weight penalty remains! “Experten” fire close up and don’t need so much. When you compare specifications do remember such little things
5.	High Altitude Performance	Barring the MiG 3, performance was poor due to single stage supercharger which limited performance above 5000 mts. Since the German bombers were at below this attitude, the German Fighters were welcome to the higher altitudes.
6	Gunsight, Transparencies, Radio	Who can beat German Optics of that time? The rest of Soviet equipment were not the best but were sturdy and adequate.
7.	Fit finish tolerance	Estimated 20 km.p.h loss at 300 km.p.h. design cruising speed. Things improved somewhat later. In field serviceability, particularly in winter, outstanding.

 

Despite the mixed bag above the Russians were often revealed profound thinking and an unhesitating willingness to copy good ideas.

When the “Bubble canopy” came the West (FW190, P47, P51 ) adopted it but spoiled things somewhat by having the rear armour plate block some of the view. The Russians used a 65 mm armour glass- an idea the copied from the Bell Aircobra which left the rear view unobstructed.

The West had self-sealing tanks but the Soviets went a step further. They, by a very simple device using copper shavings, fed their inert combustion gas from the engine into the fuel tanks, preventing fuel tanks from exploding when hit by incendiaries. The “Crude” appearance” of Russian manufacture covered profound thinking combined with excellent engineering. The Russians impregnated the wood with phenol formaldehyde resin to improve fire and rot resistance calling it Delta Derevezina “delta wood” which along with shpon, laminated birch ply formed the basis of their fighter materials. It was fire resistant.

The ability to debate the Specification

The anxiety of the Labs to get funds is so high that any debate is treated as hostile rather than contributory. The essential debates imperative for the growth of the specifications and elimination of the missteps is not institutionalized. Apart from this funds anxiety I will add that I suspect that the ADA baboos even when they know their engineering, they don’t know the domain.  That is a personal assessment from interaction- the specialist is there- the generalist is not. The Engineer and the Fighter pilots do not meet as at team but as rival or as a clerk and a customer. None of the required fission happens.

The Russian example also underlines forus  a grim reality. Quality alone will not do. We need numbers - a present 29 squadron strength air force is not 2/3rds of a 42-squadron air force- it is not 29/42 but 29/42 ²  = 0.476 in terms of combat success it is less than half of a 42 squadron air force. Our target should be 50 and it is affordable with correct policies. Tejas and Kaveri programme recovery by redesign, if necessary, by throwing all rules and shibboleths out is essential.  This kid glove handling of failing laboratories must cease. The AF cannot afford it.

Notes on the Monkey on the grease pole configurations

1.      The Tejas. It started with a developable canard concept rather like the Gripen. By a process never discussed we switched to an “undevelopable” configuration. Let me explain. It’s a fatal combination of a 13.2 mts. fuselage, 1.7 AR wings, tailless delta planform, large use of composites and FBW is as crafty development quicksand as a brilliant enemy mind can think of- and I can’t think how it came about. The fuselage is too stubby for good aerodynamics and lacks volume for equipment upgradations. If you add a “plug” to the fuselage- as is proposed to be done for the Mk2 - the weight goes up and the CG shifts. Since there is no “Stab” you have to rewire the FBW which is reportedly not modular and the 1.7 AR wing means you pay a much larger drag penalty as compared to the more common 2.2 AR. That is not all. If the prototypes were in sheet metal, modifications would be faster; composites require too long for mods. Additionally, it makes the aircraft unnecessarily expensive for export. Every “mod” creates an avalanche. “Kya Ullu banaya”. The points I have raised do not require fund . It required ability and interest in the domain.

 

2.      The Tejas Mk2. The bug is in the canard location. It will cause problems and we take a risk so that after several years wasting of time with “it’s just around the corner” someone will toothily repeat “We overpromised and under developed” and force us again to import. I may add that the Israelis “did” the Tejas Mk2 on a pirated Mirage III by adding a canard and replaced the ATAR with a very different J 75 in much less time. I suppose the IAI had unlimited fund and time that the apologists of ADA trot out as an excuse. Our present Tejas troubles were entirely self-created. -I believe -perhaps deliberately.

 

3.      The Saras. The only justified rear engine large jet was Pierre Sartre’s Caravelle. It, miraculously, was formidable. It did not make much sense in its many imitators because the turbofan came in quickly and fan scream is almost as loud a source of noise as the jet shear and thunder of the early Avon. Even in small BJs Honda is the way to go. The problem with rear engine layout is a very rearward location of the CG and the blocking of the Stabilizer- factors that contributed to the unfortunate loss of the Saras. Even had the Saras succeeded, it would run slap into the competition of the Beech 19. What is the system by which we recommend  development that would not have sold even if it had succeeded technically – bluntly -a bad proposal? Or is the old “Colonial” policy of Indian Industry should not challenge the West being covertly maintained?

 

4.      The ADE Tapas BH. We disdain back of the envelope calculations but the Tapas BH is a case of how much it could help. It is structurally an old wives tale that a load applied to the tip of a cantilever- “a flag pole bending case” suffers extraordinary deflection. It is so much an old wives tale that even I remember the formula, δ = PL³/ 3EI where δ is the deflection.  The same load on an identical simply supported beam is δ = PL³/ 48 EI. i.e. 16 times less. This is why aircraft designers try and avoid putting a stabilizer on the top of a slender fin. You get either a heavy structure or a shaky one. Now look at the TAPAS. It’s designers did not go for a “look around”, and an unknown Raja babu not only gave approval for the poor beast to have a high mounted T tail but also displayed a flair for disaster by adding this flag pole bending case to the base of the slender overlong “tadpole” rear fuselage. Do you see the problem? A “flagpole” on a “flagpole”!

 

5.      The ceiling problem of the TAPAS BH lies in this. Overweight- made worse by the criminally inadequate attention to drag reduction- caused the aircraft not to attain its promised ceiling and therefore endurance. Fitting turboprops would not be necessary if the airframe was light and drag low because of the symptoms of inadequate attention to details that the para above reveals. Pistons can go up to 12,000 mts. Now the cry is turboprops- our usual escape route of fleeing from one unsolved problem to a brand-new proposal with God knows what additional new problems.; stand by for endurance and costs issues. All this was avoidable by some intelligent copying at the time of approving the design. It is this inexpert vetting of projects- sometimes by over ruling sane advice- leading to entirely avoidable, iterations which causes disappointment, funds shortages and delay. It is painful because it could be corrected even at the design review. When a problem appears, instead of wading in to “fix” it we throw away years of work and start afresh where again we will run away from the new problems when they appear. Of course we can, after that, always blame the customer for being import addicts.

 

6.      The HJT 36. This started off as a perfectly well thought out basic design which, if a tad too large, would have sailed through the spin tests. This layout was approved up to the mock up stage. Mysteriously but following a set pattern of bad configurations turning up a second configuration appeared and was finalized which was so trouble prone by configuration that it seemed designed to create problems in spinning. The result? A delay in the programme by about decade, then BAC was called in and they gave advice any aeromodeller would have given and further confusion and hesitation until it seems HVTIAF went in and did the fixes though I still think the nicest solution would be to lower the intakes a la BAC 167.

 

Using the Funds

Finally, if we do NOT spend this awesome Rs, 65,000 crores on this project we can use it for local R&D by a responsible and accountable system. There are many relevant projects e.g. using the ISRO expertise of large rocket motor FRP casings to replace the centre fuselage tube module of the HS 748 with a CF tube. There will be significant weight savings,

There are many more like that but since this started about collaborations on engines I am giving the thought on developing our own engine.

We have the Pegasus, This can be the base engine much as the Hispano  Suiza 12Y was for the Russians. We have samples of the engine plus vast operational experience. The engine dates back to 1960 and many areas such as engine control, TET, fit, finish controls, new materials have since emerged and will benefit the new design. The scantlings of the Pegasus are 3480 mm long, 1219 dia and 1796 over the nozzles. The engine delivers 106 kN at an sfc 0.76 . The weight is 1802 kilos including the nozzle vectoring system. By all accounts it was a reliable engine. This could be a good basis for our engine without collaboration.

The wrong thing would be to set up a new GTRE design team to deliver the new GTRE V/STOL engine in 3033 for a cost of 10,000 crores i.e. the usual etc. Funded Proposals should be invited from teams like BF,L&T and the like to  A small team , no more than two or three can see what can be scrounged and what would be needed to develop the engine. Small steps within the pendency of the team leader- not till retirement sinecures.

The particular interest of the engine is based on a dis connected fact. Given the uncertainties in   the next Carrier’s configuration a Pegasus redux would be not only useful in that context but also as a possible not a TEBDF but SEBDF. Let's look at beginning with the low inertia style, It an idea that we may look at.