LCA News and Discussions

vina · Post by **vina** » 19 Jan 2011 06:50

tsarkar wrote:I fail to see how increased engine power will improve g limits/AoA/sustained turned rate, that are aerodynamic design features.

Well, sustained turn rate is heavily T:W ratio dependent. When you are pulling such high g , the drag also goes up and there is no substitute for thrust to power you through. If you dont have that thrust, you need Mother Earth's assistance via gravity by dropping height to gain the kinetic energy to do the turn.

babbupandey · Post by **babbupandey** » 19 Jan 2011 07:11

vina wrote:
tsarkar wrote:I fail to see how increased engine power will improve g limits/AoA/sustained turned rate, that are aerodynamic design features.
Well, sustained turn rate is heavily T:W ratio dependent. When you are pulling such high g , the drag also goes up and there is no substitute for thrust to power you through. If you dont have that thrust, you need Mother Earth's assistance via gravity by dropping height to gain the kinetic energy to do the turn.

Isn't there also a limit placed by airframe itself, even if you get a very fancy T:W ratio of 1.5, then the tight turns will be limited by airframe itself - the aircraft's structure may not support such tight turns.

ramana · Post by **ramana** » 19 Jan 2011 07:57

Due to limitations on funds a crash would have killed the program. In addition LCA is a statically unstable aircraft. If engine stops it drops lke rock. No glide path. It was mentioned early on by Arunachalam, the then RM advisor. As for Kaveri I already said it wasn't understood the difficulty of a turbofan and even then it was woefully underfunded.

Singha · Post by **Singha** » 19 Jan 2011 08:27

would a higher seating position for the pilot with a more F-solah style bubble canopy for improved side and rear visibility be a useful idea ?

SaiK · Post by **SaiK** » 19 Jan 2011 08:38

high wing load should also reduce maneuverability, thus reduced turn rate? also larger wings mean lower the loading (for the same load), and thus faster turn rate? so can they increase a little bit of wings for high gs in addition to the higher thrust engine?

neerajb · Post by **neerajb** » 19 Jan 2011 09:37

indranilroy wrote:^^^ Shivji, I seriously think you should take up the profession of a prof some where. (Just for pun) you already have a Dr. before your name .

You beat me to it.

Shivji you should seriously consider switching profession. Choices could be (priority wise):

1) Journalism : Your posts on BR are much more knowledgeable/informed than most DDM crap articles that one comes across these days on print media/electronic media. We need psy-ops against our stereotype DDM too to poke fun at them for their ignorance/stupidity and you fit the bill.

2) Politics : India needs a RM like you. Plus you will get votes from BR members atleast.

Cheers....

vina · Post by **vina** » 19 Jan 2011 09:45

ramana wrote: In addition LCA is a statically unstable aircraft. If engine stops it drops lke rock. No glide path.

Well that will happen if the FCS fails . Even on an engine flame out the back up batteries and (don't know probably some auxiliary power gen equipment like a ram air turbine?) can keep the FCS functional and it will continue to glide as long as it is above the minimum stall speed. I don't see any reason why that should be otherwise.

An FCS failure will be an immediate "Eject" kind of situation.

vina · Post by **vina** » 19 Jan 2011 09:48

Singha wrote:would a higher seating position for the pilot with a more F-solah style bubble canopy for improved side and rear visibility be a useful idea ?

You already have such a plane . It is the LCA Navy/Trainer , with a SU-30 style drooped nose and the possibility of having a humped back for an extra large fuel tank, by gradually tapering that bulge back into the fuselage (watch out for that in MKII, I would be willing to put money on that) like the MKI / Mig 29-K etc.

neerajb · Post by **neerajb** » 19 Jan 2011 09:51

vina wrote:Even on an engine flame out the back up batteries and (don't know probably some auxiliary power gen equipment like a ram air turbine?)

I think in Tejas's case it is Jet fuel starter. But unlike APU it is mechanically linked to the engine. So I assume that the generators will keep on generating electricity via engine powered by JFS.

Cheers....

Singha · Post by **Singha** » 19 Jan 2011 10:04

I would imagine people do not test a total FCS failure in the air, instead they test on ground static rig?
sounds like s**t scary situation to be in for a unstable fbw a/c.

suryag · Post by **suryag** » 19 Jan 2011 10:09

Dumb question has the tejas been subjected to engine relighting(shutdown and start) in air?

akimalik · Post by **akimalik** » 19 Jan 2011 10:11

The following four videos are 100% mine with no copyright issues. Only 1 is LCA. Two are ALH and one is Su-30
http://www.youtube.com/watch?v=ADdxH7oChXA
http://www.youtube.com/watch?v=7gDN9qapMz4
http://www.youtube.com/watch?v=bbbXooobp7I
http://www.youtube.com/watch?v=5lhBGOFOtK4

If you are using Linux, download WinFF and convert to MPEG 1 as needed.

Dear Shiv & Rahul Sirs,
I'd like to thank you for the videos you shared.
FYI I managed to demonstrate our Base Station application streaming an LCA video and also managed to highlight this point to the correspondent (thankfully he seemed to be aware of the LCA

).
Unfortunately, to my dismay no videos of this demonstration were made hence cannot share the moment of joy

.
All the same, I appreciate the promptness with which you shared the relevant information.
Thanks once again

neerajb · Post by **neerajb** » 19 Jan 2011 10:11

Correction:

It operates in two modes - Starter mode and Accessory mode. In starter mode, it aids in starting the engine through Jet Fuel Starter (JFS). In accessory mode, it drives accessories namely, two hydraulic pumps and an Integrated Drive Generator (IDG).

http://machinist.in/index.php?option=co ... 6&Itemid=2

I assume that the two modes cannot be engaged simultaneously. Can someone elaborate the emergency power supply system in Tejas?

Cheers....

shiv · Post by **shiv** » 19 Jan 2011 10:57

vina wrote:
ramana wrote: In addition LCA is a statically unstable aircraft. If engine stops it drops lke rock. No glide path.
Well that will happen if the FCS fails . Even on an engine flame out the back up batteries and (don't know probably some auxiliary power gen equipment like a ram air turbine?) can keep the FCS functional and it will continue to glide as long as it is above the minimum stall speed. I don't see any reason why that should be otherwise.

An FCS failure will be an immediate "Eject" kind of situation.

Here is some related info from AM Rajkumar's book

svinayak · Post by **svinayak** » 19 Jan 2011 11:22

This does not talk about total power shut off of the entire FCS bus.
There has to be some backup power mode which will keep the redundant FCS still operational.

If on an attack/damage to the aircraft there is failure of the system then there is no other option other than 'eject'

Kailash · Post by **Kailash** » 19 Jan 2011 11:38

Had a few questions regarding material research for the MkII. Could not find much information in open source.

*Composites have been on the LCA for quite a while now. Has there been any research on composites - to enhance physical properties and/or to reduce weight? I know DRDO does a lot of research on nanotubes, fullerines etc. But do we have a roadmap for transfering all this science to engineered products?
*Is there any research done by DRDO or Private sector on growth of InGaN/GaN substrate (leave alone power electronics circuits T/R modules etc)?
*DRDO was experimenting with a gold plating over the canopy, newer radar absorbant paints etc. How much of this would make it on to the Mk-II? Has there been any further research on the RCS reduction?
*Is GTRE/DMRL still trying for a breakthrough on productionizing SC blades and BLISK or have they frozen research in this area?

Kailash · Post by **Kailash** » 19 Jan 2011 12:41

ARDE, HEMRL scientists ensure pilots’ safety in Tejas

Lessons learnt during the development of CSS for Tejas have been used for developing CSS for other aircraft.

Wonder which other aircrafts they are talking about!

pralay · Post by **pralay** » 19 Jan 2011 14:00

Kailash wrote:Wonder which other aircrafts they are talking about!

What else do we have

LCA Navy, IJT and may be a secret project for AMCA like china

babbupandey · Post by **babbupandey** » 19 Jan 2011 14:15

I think they meant Navy LCA because MCA is yet to materialize.

tsarkar · Post by **tsarkar** » 19 Jan 2011 14:36

vina wrote:If you are doing an ab-intio design, then it is a different story.

Tejas and examples I give below are ab-initio

vina wrote:In a warship, you need that kind of design database from experience and so is a different ball game! Same with an aircraft like the LCA.

For Tejas or IN ships, there was no design database available, so everything had to be developed from scratch.

vina wrote:The thing is if you notice, all these are not major efforts UNLESS you build a full ship for every iteration! At design stage it is all on paper /computer memory and can be easily fiddled with in few lines drawn or clicks of mouse. It is always a truth that changes are nearly painless in initial design and the later you are in the cycle of the product, the cost and pain of changes shoot up!.

This is where we have a difference of opinion.

No one builds a full ship, but tank test models. And EVEN with models, it is a very time consuming process.

In the old Talwar frigate, a decision was taken to replace the forward 4.5’’ guns with P-15 missiles launchers taken from old Osa boats. Now, in a ship design process, you make tank models, etc , and broadly follow the iterative process described by you. However, time constraint (old Talwar didn’t have ample service life remaining to accommodate a lengthy design & development time) & budget (not worth investing a paisa more than necessary, since it took funding away from Leander/Godavari projects). Same were the issues during adding ski-jump to Vikrant. So the process described by Kartik was followed

Another example - http://indiannavy.nic.in/t2t2e/trans2em ... ect_25.htm

But I believe the Soviets insisted that the bridge structure should go further aft. And it got shifted. I would not have permitted that to happen. It caused some trim problem which had to be adjusted by other means.

As discussed, simply no time or money to do an iterative process, and its past the Computer Aided Design stage, so only option left is jugaad design process.

Also note that we don’t have a ready supplier base. Warship/Aircraft components are specialized and cannot be shared with commercial ships/civil airliners. Very few manufacturers are willing to build them because the manufacturing process requires investment for a very limited production run. The reason why IN buys/build 12 Leander (6N+3G+3B) or 9 Talwar (3T+3T+3S) or 10 Delhi (3+3+4) is to ensure commonality in system & components to drive cost down.

Now, does this sound familiar?

When you are working on a Naval Staff Requirement and when the total project starts sliding back 18 months, everybody gets fresh ideas. Fresh weapons, fresh helicopters, fresh radars, fresh sonar and everyone wants to pitch in. That has a very deleterious effect.

Issue with Tejas was the end users did above, and the designers chose the most advanced technological option available (hence risky), and the chances of making ends meet diminished there & then itself. A good program manager would have been able to push back anything - from both sides - that increased project risk. The desire to increase composite percentage, etc, was meaningless vis-a-vis delivering the required capability to the field.

Lalmohan · Post by **Lalmohan** » 19 Jan 2011 14:39

^^^ so actually what is lacking is a national military technology strategy and policy spanning multiple ministries

the french do this quite well i think (worth learning from)

Philip · Post by **Philip** » 19 Jan 2011 17:01

AKA's decision to stall FDI in defence at 26% against intense pressure to raise it even higher is laudable,as the aim is to get local corporate entities into the defence industry along with PSUs meeting the majority of defence needs within the country,so that the "holy grail" of indigenisation can be pursued asap.It is imperative that as far as defence goes,India should possess a sound technological base from which the majority of its defence needs are met at home,ensuring a seamless supply of weapon systems and components at any time,peace or during a crisis in adequate number.Where this is not possible,JVs with friendly countries/manufacturing entities as is beinbg done with Brahmos is preferable.Where we do not have the capability or need to augment our numbers rapidly foreign purchases allied to local production TOT can be the method of the moment-as is being planned with the MMRCA case,but as has been shown in the past,even excellent foreign platforms/systems have needed to be fine tuined/modified to meet our unique requirements,thus neccessitating that an increasing number of systems should be designed and manufactured indigenously.This way we will be able to get the best out of both local innovation in design and cost-effectiveness in production as well as the tech knowhow from collaborating foreign entities.Brahmos and the FGFA programmes are excellent JV models,while Arjun,the LCA and the variety of naval programmes show how we can lead a programme through indigenous design and incorporate key components,weaponry,etc, which we do not possess into the overall deisgn.

Kanson · Post by **Kanson** » 19 Jan 2011 18:20

tsarkar wrote:
When you are working on a Naval Staff Requirement and when the total project starts sliding back 18 months, everybody gets fresh ideas. Fresh weapons, fresh helicopters, fresh radars, fresh sonar and everyone wants to pitch in. That has a very deleterious effect.
Issue with Tejas was the end users did above, and the designers chose the most advanced technological option available (hence risky), and the chances of making ends meet diminished there & then itself. A good program manager would have been able to push back anything - from both sides - that increased project risk. The desire to increase composite percentage, etc, was meaningless vis-a-vis delivering the required capability to the field.

Push back? with IAF ? Few posts above a page from Rajkumar's book describing the futility of such exercise in pushing back IAF's demand.

The desire to increase composite percentage

Did you mention "desire" as a desire by loony lab rats to show cause his skills and to earn his reputation? My Goodness.

Lalmohan · Post by **Lalmohan** » 19 Jan 2011 18:25

i suspect that senior IAF officers have not been attending their Mil-Eng complex strategy lectures at staff college!

tsarkar · Post by **tsarkar** » 19 Jan 2011 18:33

Lalmohan wrote:^^^ so actually what is lacking is a national military technology strategy and policy spanning multiple ministries

What is required is pragmatism. All programs that succeed are pragmatic, all that don’t were unrealistic to begin with. US FCS, LCS, JSF program were unrealistic in the first place. For JSF, the focus on commonality compromised in-field capability.

When Godavari was built, it used old Leander hullform and engines, and increased capability by 10% on the Brooke and Garcia class frigates then used by Pakistan, as well as for engaging Agostas, Orions & Mirages. Delhi + Brahmaputra are derived from old Kashin & Leander, and respectively offer 10% capability advantage over their contemporary Chinese counterparts. So does Shivalik and Kolkata.

The focus should always be on capability.

A realistic goal for Tejas would have been a fighter 10% more capable than F-16 Block 15 used by Pakistan, agnostic to metal/composites, light/heavy, small/large.

In the field, I personally won’t mind flying an Il-76 sized fighter, provided it is 10% more capable than F-16 Block 15 in every relevant performance aspect.

In WW2, plywood Mosquitoes beat German planes made of advanced aluminum alloys simply because the plywood Mosquitoes were more capable.

tsarkar · Post by **tsarkar** » 19 Jan 2011 18:53

Kanson wrote:Push back? with IAF ? Few posts above a page from Rajkumar's book describing the futility of such exercise in pushing back IAF's demand.

And this is where a strong program manager could have made a difference. Like here

I believe the Soviets insisted that the bridge structure should go further aft. I would not have permitted that to happen.

For Tejas, the Program Manager could have escalated to ministry stating IAF requirements were beyond available means, and overkill for present threats, and non-conducive to the stated program goal of indigenization.

Kanson wrote:Did you mention "desire" as a desire by loony lab rats to show cause his skills and to earn his reputation? My Goodness.

Directed at whosoever arrived at the 5500 kg figure. Directed at whosoever believed composites could fulfill that expectation. In the event the relevant Subject Matter Expert knew/discovered that composites could not fulfill the stated expectation, he/she could have raised a red flag to Program Management that the expectation was unrealistic, and Program Management could have undertaken course correction.

I certainly dont want to act smart by passing comments without knowing the actual challenges faced by those on the job. However, I want to learn from failures, and incorporate best practices from wherever we succeeded.

nachiket · Post by **nachiket** » 19 Jan 2011 19:13

tsarkar wrote:
A realistic goal for Tejas would have been a fighter 10% more capable than F-16 Block 15 used by Pakistan, agnostic to metal/composites, light/heavy, small/large.

In the field, I personally won’t mind flying an Il-76 sized fighter, provided it is 10% more capable than F-16 Block 15 in every relevant performance aspect.

Sir, the LCA was meant to replace the huge numbers of Mig-21s in IAF service. A fighter 10% more capable than the F-16 in all aspects would mean a larger, heavier and consequently more expensive aircraft. When the LCA project was started, could India afford to replace each Mig-21 with such an aircraft? This was the late 80s. Our economy was a complete mess and the immediate future looked bleak.

Kanson · Post by **Kanson** » 19 Jan 2011 19:16

Juggi G wrote:A Beam of Light
The Indian Express
By
Admiral Arun Prakash PVSM, AVSM, VrC, VSM, Indian Navy

Is this piece from Arun Prakash? Wonderful!

Both these strategic and prestigious platforms are on the threshold of entering service, but with a fairly arduous road to traverse before attaining fully operational status.

The LCA project attracted maximum criticism because of the time it took and the cost overruns it had.

Why not about ATV ? If Navy and BARC allowed any close scrutiny of its ATV programme, it too face criticism as much as and much more than LCA. Navy doesn't like its projects to be discussed, period. Point is whether it is ATV or LCA, it is the first time such a project was taken and the technology advancement to be tackled is immense. No point in talking about cost overrun or time overrun in this fashion as Shiv Aroor done it some years before.

Obviously, the DRDO over-estimated its own competence. This led to the ambitious claim that they had the capability to develop, in-house, not just the airframe and engine, but also the radar as well as a complex fly-by-wire (FBW) flight control system required for an “agile” (or aerodynamically unstable) fighter. This blunder was compounded by trotting out hopelessly optimistic cost and time estimates, on the incorrect premise that since India had earlier designed and built the HF-24 Marut, we possessed the design skills and manufacturing expertise.

When India bought INS Vikrant from UK, India didn't have any experience in operating ships like Aircraft Carrier. Then why was the then IN Captain of Vikrant insisted in commandeering the Ship all by himself when his counterpart, RN captain preferred a joint commandeering with him as IN was inexperienced in handling such ships?

What was the IN reaction to Vikrant Captain's behaviour? Was he admonished, court martialed for his attitude for commandeering the ship when there is no prior experience?

What is the lesson, if any, to be learnt from IN Captain's behaviour?

I guess, as Adm Arun Prakash became writer and editor, i think, i should expect from him what should be expected from similar groups.

Kanson · Post by **Kanson** » 19 Jan 2011 19:33

tsarkar wrote:
Kanson wrote:Push back? with IAF ? Few posts above a page from Rajkumar's book describing the futility of such exercise in pushing back IAF's demand.
And this is where a strong program manager could have made a difference. Like here
I believe the Soviets insisted that the bridge structure should go further aft. I would not have permitted that to happen.
For Tejas, the Program Manager could have escalated to ministry stating IAF requirements were beyond available means, and overkill for present threats, and non-conducive to the stated program goal of indigenization.

Sir, the Program Manager, Kota, was new to the Job then in 80's. The Original program manager who is well experienced in such endeavors was kicked out. Rumour was that somebody was not comfortable with his overbearing attitude - only rumour. Making assessment in a fashion of 2+2=4, the uneasiness *could* have been from IAF. What can be expected from such a person new to the job?

Kanson wrote:Did you mention "desire" as a desire by loony lab rats to show cause his skills and to earn his reputation? My Goodness.
Directed at whosoever arrived at the 5500 kg figure. Directed at whosoever believed composites could fulfill that expectation. In the event the relevant Subject Matter Expert knew/discovered that composites could not fulfill the stated expectation, he/she could have raised a red flag to Program Management that the expectation was unrealistic, and Program Management could have undertaken course correction.

Sir, from reading, the composite level is raised to the present level to decrease weight. Original composite level planned is less than the current level.

vic · Post by **vic** » 19 Jan 2011 19:50

Lets forget about who pushed out whom and concentrate on today!!!!!We need to put way more money and effort in LCA programme. Things like composite tech, metallurgy, aviation grade aluminum, FBW, wind tunnel modeling, simulator development, canopy, ejection seats, Oxygen systems, actuators, hydraulic systems, avionics, HUD, HOTAS, HMS, ECM, DRFM, DIRCM, jammers, Pylons, RLGs, etc etc helps in "whole" aerospace development and not only in LCA. LCA +Kaveri can easily be the base for UCAV. Even ssuming that empty weight of LCA Mark-1 batch1 (for SP 1 to 10) will be 7500 kg and will go down to 7000 kg till 40th SP with 83kn F404IN20 engine, even then I think that we should order atleast 60-80 Mark-1s. We should order 150 LCA AJT with Kaveri. Then we should order 150 Mark-2s and develop UCAVs on the offshoots.

Vivek K · Post by **Vivek K** » 19 Jan 2011 20:21

The problem with Indians is that though most of us do not know much about the subject at hand, we like to put our "expert opinion" as THE opinion for all to follow. The LCA has thankfully escaped the meathooks of this and has scraped through. It will live on despite being 3 legged, not 10% (like Zardari), not 15%, not 20% or any such thing.

Folks let those that are the most knowledgeable INDIANS in this field do their thing. Do not pull them down without understanding their limitations or operating environment. A ship is different from a plane, from a tank, from a space launch vehicle and a satellite. Each needs different expertise. Just like Ajai Shukla would be better off talking about Tanks and things Army, others may need to stay with ships and things Navy. Otherwise it may make for smaller bandwidth for genuinely knowledgeable opinions.

tsarkar · Post by **tsarkar** » 19 Jan 2011 20:52

Kanson wrote:the Program Manager, Kota, was new to the Job then in 80's.

I agree we cannot change the past, I'm only citing the role played by effective program management in a successful project.

Kanson wrote:Sir, from reading, the composite level is raised to the present level to decrease weight. Original composite level planned is less than the current level.

My understanding from speaking with people associated with the project is that it uses a mix of metal & composites. Composite panels on metal frame in the fuselage, and this arrangement doesnt provide the expected returns. Also, the approach has been replacing a metal part with a composite part, which isnt the optimum way. But this discussion is immaterial to my point, which is to focus more on ends(capability), rather than means(metal or composite or reverse engineering)

ramana · Post by **ramana** » 19 Jan 2011 21:14

TSarkar, Co-cured composite gives maximum savings in weight but is also very risky technology wise. The other alternative of composite panels on metal fittings is achievable. However it leads to "black" aluminium designs i.e. composite replace metal parts but don't take advantage of the composite material properties. All in all its great for the first design.

BTW thanks for insight on the Leander's and Godavari's requirements and how they were met.

I agree all programs should go thru lessons learned. While these could be not public, the open discussions inform the public of the complexity and challenges faced by the programs.

vina · Post by **vina** » 19 Jan 2011 21:20

tsarkar wrote:Tejas and examples I give below are ab-initio

This is where we have a difference of opinion.

No one builds a full ship, but tank test models. And EVEN with models, it is a very time consuming process.

Well, no one builds a plane either (or a car either for that matter)without a wind tunnel model! And oh, I have seen models in towing tanks. Building a wax model hull and doing a resistance and powering test in a towing tank is a fortnight's job at max, once the line drawings are done. You just need a couple of skilled carpenters for that. That model part is not time consuming as you say.

In the old Talwar frigate, a decision was taken to replace the forward 4.5’’ guns with P-15 missiles launchers taken from old Osa boats.

The Tejas was ab-initio. This kind of thing wasn't. It is at best some modification, and that too that probably didn't require too much change and was well within the tolerance limits of the original design.For eg, changing the gun to P-15 missile launch wasn't going to change the displacement of the boat by 20% (which is what happened in Tejas). If you said you Jumboised the Talwar, I agree that was pretty serious business and you couldn't have done that without serious design and analysis and simulation/testing. The Tejas weight gain is something like Jumboisation!

Also note that we don’t have a ready supplier base. Warship/Aircraft components are specialized and cannot be shared with commercial ships/civil airliners. Very few manufacturers are willing to build them because the manufacturing process requires investment for a very limited production run. The reason why IN buys/build 12 Leander (6N+3G+3B) or 9 Talwar (3T+3T+3S) or 10 Delhi (3+3+4) is to ensure commonality in system & components to drive cost down.

The economies of scale happens lot more in the civilian world. In fact, many shipyards have standard designs for multiple displacements for a particular ship type and then scale from the closest fit with minimal changes if you want a custom one, so they get to aggregate multiple orders around a common base line and get scale economies!

On the lack of applicability of civilian stuff to defense, I think those days are well and truly past. In the bulk of electronics and controls, the trend is towards Commercial Off the shelf stuff (COTS), days of very specialized custom built stuff are nearly over. In fact, most civilian systems , contrary to urban legend are built to far higher standards (engines and other systems.. a 100,000 ton bulker has a single engine driving a single screw and covers millions of miles in it's life time.. far far higher than nearly every Naval ship and any downtime/failure is very expensive to the owner.. take the take-off and landing cycle of a commercial airliner such as an A320/B737 or even a large one like 777/747 vs the cycles and miles on a military cargo plane..) .

Of course, some stuff will be distinct, and will call for specialized designs (for eg,battle damage tolerance in a warship, vs something like civilian ship which probably calls for survival if two adjacent compartments separated by a bulkhead are flooded ..in warships, you will have longitudinal bulkheads as well, in addition to transverse bulkheads in all probability).

All in all, military construction and design is really not that different.

.. A good program manager ..

The lack of program management has been a bane of Indian programs . But that said, it is partly a lack of maturity and capability on the defense forces (IA and IAF in particular) as well. Add to that the huge pumpkin sized egos of the top brass who think they are the know all and end all (bah.. civilians.. harrumph, we always know best..) and come from an org culture where "unquestioning obedience is expected , instilled and enforced", they most probably wont have the maturity and mental background if someone pushed back and challenged them on what they wish to do. That has been a learning for the defense forces I think from the ongoing projects.

Lalmohan · Post by **Lalmohan** » 19 Jan 2011 21:20

there are limits to composite uses. generally fine in tension but not in compression loading - so have to be used selectively

vina · Post by **vina** » 19 Jan 2011 21:26

tsarkar wrote:Composite panels on metal frame in the fuselage, and this arrangement doesnt provide the expected returns. Also, the approach has been replacing a metal part with a composite part, which isnt the optimum way.

Well, the kind of fuselage design you are talking about has not been implemeted in any fighter anywhere in the world yet (even the F22 doesnt have it, but uses a Tejas like design). The only places they have been implented are small business jets (esp Hawker 200) and notably the B 787 (which has seen such huge schedule slippages precisely for that reason)

But this discussion is immaterial to my point, which is to focus more on ends(capability), rather than means(metal or composite or reverse engineering)

Unfortunately you cannot separate the ends and means here. To use a Navy analogy, if you want your submarine to stay indefinitely underwater without surface, you need nuclear propulsion. Without that there is no way out . It is something similar. If you want that level of performance, you need that level of technology. There is no other way out.

vina · Post by **vina** » 19 Jan 2011 21:30

Lalmohan wrote:there are limits to composite uses. generally fine in tension but not in compression loading - so have to be used selectively

Composites are not good for impact loadings and failure mode is very different from metal (sudden cracking vs collapsing).

That is no reason for anything. What you said, similar reason is true for cement as well. Massive strength in compression but zero in tension! Does that mean that you stop using cement?. Look at all the buildings around and see what they are made of (now you know whey the lay out a steel rods inside the concrete).

Lalmohan · Post by **Lalmohan** » 19 Jan 2011 21:48

er no... i am a big fan of composites, but when used correctly

Nirmal · Post by **Nirmal** » 19 Jan 2011 22:04

Kailash wrote:Had a few questions regarding material research for the MkII. Could not find much information in open source.

*Composites have been on the LCA for quite a while now. Has there been any research on composites - to enhance physical properties and/or to reduce weight? I know DRDO does a lot of research on nanotubes, fullerines etc. But do we have a roadmap for transfering all this science to engineered products?
*Is there any research done by DRDO or Private sector on growth of InGaN/GaN substrate (leave alone power electronics circuits T/R modules etc)?
*DRDO was experimenting with a gold plating over the canopy, newer radar absorbant paints etc. How much of this would make it on to the Mk-II? Has there been any further research on the RCS reduction?
*Is GTRE/DMRL still trying for a breakthrough on productionizing SC blades and BLISK or have they frozen research in this area?

On material research, In Holland they have discovered an new Aluminium Alloy which is much much lighter than composites or titanium but much much stronger in tensile strength. This can be the answer to Tejas Mk3 or AMCA. Besides in Boston, USA, they have discovered glass that is very light in weight but stronger than any known steel(Answer to Glass Cockpit and shield/Canopy?). Our R&D into material Science is indeed very poor and behind the current field discoveries and we desparately need to catch up.

SaiK · Post by **SaiK** » 20 Jan 2011 00:32

glass! you mean graphene.. it was just (2010) discovered by the russkie nobel prize winners. Now a long way to go, and of course our folks would have noted this exciting new material. CFC->GFG?