Ask anything Thread (Air Force)

[duskylim]

Thank you for the informative replies. I very much appreciated them.

It is undeniable that India sought to independently produce a domestic fighter starting from a low base, and although she has suffered some setbacks, nevertheless has produced some very good and worthwhile results.

Learning from this, ultimately we will see a domestic fighter emerge. Perhaps just not so soon.

But from the Indian Air Forces' point of view, was it too ambitious for the ADA and Defense Ministry promise this as their replacement fighter?

Why not just initiate it as a technology demonstrator and thereby NOT commit the IAF to buying them?

As it is, the Indian Air Force is now in a sort of a scramble to find a replacement to make up the numbers.

 

[Zool]

But from the Indian Air Forces' point of view, was it too ambitious for the ADA and Defense Ministry promise this as their replacement fighter?

Why not just initiate it as a technology demonstrator and thereby NOT commit the IAF to buying them?

As it is, the Indian Air Force is now in a sort of a scramble to find a replacement to make up the numbers.

They were not going to approach the LCA program as a tech demonstrator because they knew they would be facing a need for replacement aircraft in large numbers, so the expectation was to develop a viable fighter that had modern capabilities and could be manufactured domestically.

It's difficult to discuss without potentially coming off as offending Indian efforts, but I think in the view of HAL and the IAF initially, previous efforts with the

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fighter proved that India had a base knowledge and capability to design and manufacture a fighter in the class of Tejas. But that turned out not to be the case.

India did some design consultation in the US and conducted all of the Wind-Tunnel testing there. Beyond that however, they had planned for all of the sub-systems, radar and even the engine (Kaveri) to be developed and built domestically. The technology and infrastructure base was just not there to make that happen and aggressive timetables promised by HAL were not met. Over the years they transitioned a number of systems to foreign vendors to try and get the aircraft FOC and in production, but they are now having some problems with integration and certain aspects not meeting design specification (weight, effective radar range, itr/str etc).

I think the biggest problem today is with the IAF-MoD in getting acceptance for the MK1 and firm orders to establish the manufacturing and supply chain. You'll notice that in contrast, Pakistan was willing to take an evolutionary approach to the JF-17 and get it flying now while integrating additional weapons and capabilities like IFR in later blocks. China being the sole component supplier, save for the engine, also means it does not have the same integration and design validation problems as Tejas, which has components from multiple foreign and domestic suppliers...

So in short (lol) yes, the LCA program was overambitious to begin with based on where India was starting from technology and industry wise (although ambition itself is not a bad thing so long as you keep an eye on timetables and remain realistic). Now with time and technology having moved on, the IAF does not appear to be willing to accept an evolutionary approach and instead wants a premium model, otherwise it is happy to import a fully foreign solution.

 

[duskylim]

Perhaps because Pakistan was acutely aware of it's restrictions that it limited the specifications and local content of the JF-17, and accepted Chinese direction.

I remember the first rumors which characterized it as a Super-7 or J-7 derivative, which ultimately turned out to be false.

But what seems to me to be very important (from the programmatic point-of-view) is that they did not demand the latest and best, and rather relied on well-established (though not cutting-edge) solutions.

This resulted in a small but capable fighter, with a clear upgrade paths. One that could be assembled in Kamra and over time, could get increasing local content.

India had similar needs, basically because it used the same fighter (the MiG 21) as its mainstay.

The Tejas' airframe and controls, locally designed and built were a success, but the engine, radar and other avionics were more difficult.

Should they have designed it (the Tejas) from the very start with the option of having these components sourced from outside should the domestic efforts be delayed?

That way they could have avoided the situation they are in now.

 

[Zool]

To be fair, comparing the JF-17 program with India's LCA effort is really an examination of the Chinese Aerospace Industry versus India's. On that,China has a significant lead for a multitude of reasons we don't really need to cover here.

When looking at JF-17 from the Pakistan perspective, they seem to have taken a successful approach in having certain materials and systems still manufactured in China but transitioned to local Pakistani production over time. So while the adding of capability has been incremental between blocks, so too has the amount of local manufacture in Pakistan.

The closest India has come to this level of cooperation in it's own Aerospace industry has been with Russia and the Su-30 program. But I think the depth of knowledge and technology transfer between China & Pakistan in the JF-17 is significantly greater.

Should India have designed Tejas to use more import systems from the outset? My opinion is no - they should have modified the design around available indigenous systems and accepted their newly developed systems, even when they did not fully reach specification (baring safety issues), with the mind of improving all areas of the aircraft and associated MIC in block upgrades. Mark 1 of a Mig-21 replacement aircraft should have been out some time ago...

 

[[email protected]]

What was it that made the JF-17 project so successful while the Tejas project seems to be in trouble?

A simple answer 'Project Management' is the only reason between the said two Fighter Jet projects.
Tejas can still be successful plane only if Indian give up their attitude of over experimenting with this project ....

 

[Deino]

A simple answer 'Project Management' is the only reason between the said two Fighter Jet projects.
Tejas can still be successful plane only if Indian give up their attitude of over experimenting with this project ....

AMEn to that !

If You read the very interesting history "The Tejas Story" written by Air Marshal Ph. Rajkumar (ret.) already in 2008 and remember what happened in the meantime, one can only cry.

It reminds me so much on what the Chinese aviation industry wanted with its J-9 program: more, more, and more again. All that "more" completely alone and once a design was finalised, the PLAAF, the politics or what/who-ever came and wanted more again.
In the end the industry nor the technology itself necessary was not mature enough ... and all failed.

And with the Tejas history seems to repeat at least in parts: Why on earth so many different versions, subtypes, subversions and so on ...
- Tejas demonstrators
- Tejas prototypes and preserials...
- Tejas Mk.1 serials
- Tejas trainer
- Tejas naval trainer
- Tejas naval Mk.1
... and then they find out, they need a new engine that does not fit the airframe, that requires a redesign ... and so we will have again:
- Tejas Mk. 2
- Tejas Mk.2 trainer
- Tejas naval trainer Mk. 2
- Tejas naval Mk.2

These are more iterations than any other modern combat type had in its whole service career.

Overall it's like wanting to make step 2 before step 1 is already completed. Radar, avionics, cockpit, engine materials and design itself ... sad, truly sad.

Deino

 

[no_name]

I have a question. When an aircraft is travelling faster than the speed of sound it produces various shock cones from it's leading surfaces. Usually a stable design requires that the aircraft hides behind the shock front, which is why faster planes are more elongated and have more swept back wing.

My question is what about formation flying? If a formation of fighter jets were travelling past the speed of sound together, will the shock waves generated from one aircraft have an impact on neighbouring aircraft behind it? Are there special rules regarding flying supersonic in formation i.e. minimum distance and formation layout etc? Does it dissipates to be negligible past a certain distance from the aircraft?

I think maybe if they are flying side by side and separated wide apart enough, they would be in front of each other's shock cone. Or if flying behind then hide behind the cone of the aircraft in front of them.

 

[Air Force Brat]

I have a question. When an aircraft is travelling faster than the speed of sound it produces various shock cones from it's leading surfaces. Usually a stable design requires that the aircraft hides behind the shock front, which is why faster planes are more elongated and have more swept back wing.

My question is what about formation flying? If a formation of fighter jets were travelling past the speed of sound together, will the shock waves generated from one aircraft have an impact on neighbouring aircraft behind it? Are there special rules regarding flying supersonic in formation i.e. minimum distance and formation layout etc? Does it dissipates to be negligible past a certain distance from the aircraft?

I think maybe if they are flying side by side and separated wide apart enough, they would be in front of each other's shock cone. Or if flying behind then hide behind the cone of the aircraft in front of them.

My inclination at first was they can't be too close, after thinking about it, most supersonic fighters accelerate right through the sound barrier with minimal fuss these days, and as you noted, supersonic aircraft always have wings with an aft sweep, inboard to outboard.

There are lots of things happening as you pass through the sound barrier, and one of those rather in-explicable things is "mach-tuck", the nose pitches down, which has to be counter-acted by positive pitch application??

I believe that is one reason the forward lifting body concept is so popular with this category of aircraft as it naturally applies lift to the forward fuselage.

 

[taxiya]

Overall it's like wanting to make step 2 before step 1 is already completed.

Deino

That is a spot on.
There is a saying in Chinese, "learn to walk before running". The Chinese approach, except the crazy years during the Culture Revolution (J-9), is fast walking with small steps.
Many Chinese projects besides J-9 have taught Chinese hard lessons, I hope India will learn it from LCA. Growing pains, everyone experience it.

 

[delft]

My inclination at first was they can't be too close, after thinking about it, most supersonic fighters accelerate right through the sound barrier with minimal fuss these days, and as you noted, supersonic aircraft always have wings with an aft sweep, inboard to outboard.

There are lots of things happening as you pass through the sound barrier, and one of those rather in-explicable things is "mach-tuck", the nose pitches down, which has to be counter-acted by positive pitch application??

I believe that is one reason the forward lifting body concept is so popular with this category of aircraft as it naturally applies lift to the forward fuselage.

There are many aircraft with wings that have a leading edge sweep less than the Mach cone angle. Remember F-104, F-5?
On subsonic wing profiles the lift force centers on the quarter chord point, on a supersonic wing profiles at the 50% point. So the lift vector moves aft when going supersonic.