Tejas Mk.1 & Mk.1A: News & Discussions: 23 February 2019

[souravB]

People who are concerned about the per unit price of Tejas, I would advise to please read up on Mitsubishi F-2 fighter and specifically it's unit cost. Though it is based on F-16, it is almost a new fighter due to design changes. That is the price Japan paid to establish a aerospace supply chain. It had many world's first tech on a fighter plane but they don't have the IP although spending exclusively for the D&D.
Same situation can be extrapolated to India's Su-30MKI. We made many changes that led to a higher unit cost and almost a new fighter that Russia is fielding as Su-35 with some more mods.

[MeshaVishwas]

I think you mean they mooched off our cash to come up with the SM variant?

[Indranil]

ShivS,

Nobody is happy with the price quoted by HAL for Mk1A. There is a committee constituted to look into the price rise.

But your post is pretty shallow. Do you know the breakup of the cost of Mk1A? Why should an Indian produced Gripen A/B-equivalent cost the same as a JF-17? Also, do you know the cost break up of F-16/Gripen C/D. Last time I checked, the flyaway cost of a Rafale is 100 million, but the acquisition cost is nearly 300 million.

So, I request you to put some flesh behind your post instead of trying to instigate.

[Kartik]

Is the Mk1A worth it at a quoted price of nearly Rs485 Cr? It’s a combination of 4.5 gen avionics, radar, EW and communications with a 3rd generation payload and endurance!

Unless HAL figures out a way to drop the cost to around Rs.325/350 Cr doubt the IAF will bite, and they should not!

If the MK1 costa around Rs.240/250 Cr, the improvements requested should not add more than Rs75/100 Cr to the cost. Make in India is important but this verges on the ridiculous!

Two things I have an issue with in this post

1) Rs 485 crore price tag. That is the program cost per unit which will include the cost of development. Yes, even HAL has to pay its employees and suppliers for several internal and external software and hardware development and integration projects specific to Mk1A, it does not come free. It'll also include the money required for the thousands of hours that will be required for testing avionics, systems that are being changed, etc. and flight testing. There'll be a lot of other costs that may be non-recurring as well.

In the real world, if you want something new, you'll have to pay. Most of the money is being spent within India and being splurged on an imported platform, so what's the big problem?

2) What is the benchmark for a light 4.5 gen fighter against which you're benchmarking the Tejas Mk1A's payload and range? I really want to know, because the Tejas Mk1 and Mk1A are not really payload hobbled as much as hardpoint restricted. And that is being tackled to some degree by multi-rack pylons.

After the February encounter, I really feel that increasing the missile flexibility is important. Want to see Tejas fighters carry 3-4 BVRAAMs and 2 or 4 CCMs plus drop tanks and SPJ on any such missions that they may have to carry out. And that would require new mid-wing pylon that can carry 2 BVRAAMs instead of just 1.

You mentioned endurance, whereas I don't believe you should use that term. Given that the Air to Air refueling probe allows for missions that will last a few hours depending on how much LOX is carried onboard or pilot fatigue or availability of refueling tankers. Basically a 2X to 3X jump in endurance over existing Tejas Mk1 and most non probe equipped fighters.

[Arun.prabhu]

Wrong. RCS is a function of shape, size and material. Two different objects with same shape and made from same material will have different RCS with the smaller one having lower RCS.

I wonder how RCS changes from Mk1 to Mk2 given Mk2 is bigger and has canards.

RCS is a function of shape and not size. (If you see theoretical calculations, an object of same external shape where as little as a small jet or as big as a ship would have same RCS..!! Canards need not mean increase in RCS always.

Now that you mention it, Canards on MK2 have slight dihedral angle. I wonder if that would help in negating any possible impact of canards on frontal RCS.

[JayS]

^^ Ben Rich, who was program manager for F117 program, wrote in his book, and I quote:

"He told me later that he was surprised to learn with flat surfaces, the amount of radar energy returning to the sender is independent of the target's size. A small airplane, a bomber, an aircraft carrier, all with same shape will have identical radar cross section. "By God. I never would have believed that.""

'He' in this quote is Kelly Johnson.

I remember this one distinctly precisely because its counter intuitive. I think I saw the same thing in one documentary on F117 as well, but that may be my mind playing tricks due to my rather fuzzy memory.

On a second thought, I wonder if this is only applicable for a faceted design like F117, but then any shape can be thought to be made up of tiny facets. Indeed the computational RCS measuring codes must be using the same philosophy.

May be someone with expertise in RCS can clarify.

[tsarkar]

1. Don't the Canards reduce the overall visibility ? Additionally IMHO the enlarged fuselage behind the canopy also contribute s to the reduced rear ward visibility.

Rear view mirrors are used to see back. It’s impossible to twist the neck pulling “g”s

2. Accessing the 2nd seat in a twin seater MK2/trainer will be tricky with those canards. Gipen barely manages with a complex ladder with a flat platform, but in Gripen the Canards are lower and hence better placed.

Mk1 Trainers would be used. No MWF trainers have been conceptualised.

[Indranil]

The canard does come in the way, but in a sector where no pilot sees. So the canard on the MWF would hamper vision no worse or better than a Rafale/gripen.

But compared to a mk1, the visibility should be actually better, given that the wings are set further behind.

[Pratyush]

I don't think we have a cost per item breakup of items that are going into the mk1a. For us to say it is expensive or not.

[alexis]

^^ Ben Rich, who was program manager for F117 program, wrote in his book, and I quote:

"He told me later that he was surprised to learn with flat surfaces, the amount of radar energy returning to the sender is independent of the target's size. A small airplane, a bomber, an aircraft carrier, all with same shape will have identical radar cross section. "By God. I never would have believed that.""

'He' in this quote is Kelly Johnson.

I remember this one distinctly precisely because its counter intuitive. I think I saw the same thing in one documentary on F117 as well, but that may be my mind playing tricks due to my rather fuzzy memory.

On a second thought, I wonder if this is only applicable for a faceted design like F117, but then any shape can be thought to be made up of tiny facets. Indeed the computational RCS measuring codes must be using the same philosophy.

May be someone with expertise in RCS can clarify.

I am no expert but from memory, rcs depends on the size (surface area) of the target also (alongwith material of the target,incident angle and wavelength of the radar wave)

[Arun.prabhu]

https://en.m.wikipedia.org/wiki/Radar_cross-section

Size is also a factor. It is just that shape and material have far more impact.

^^ Ben Rich, who was program manager for F117 program, wrote in his book, and I quote:

"He told me later that he was surprised to learn with flat surfaces, the amount of radar energy returning to the sender is independent of the target's size. A small airplane, a bomber, an aircraft carrier, all with same shape will have identical radar cross section. "By God. I never would have believed that.""

'He' in this quote is Kelly Johnson.

I remember this one distinctly precisely because its counter intuitive. I think I saw the same thing in one documentary on F117 as well, but that may be my mind playing tricks due to my rather fuzzy memory.

On a second thought, I wonder if this is only applicable for a faceted design like F117, but then any shape can be thought to be made up of tiny facets. Indeed the computational RCS measuring codes must be using the same philosophy.

May be someone with expertise in RCS can clarify.

[Kartik]

http://delhidefencereview.com/2019/02/2 ... t-fighter/

Updated second part. We added a few interesting points on LCA wing design. Do read to know why Tejas has lower sweep on inboard section or why the inboard section looks like it has anhedral (but it doesn't). We have had discussed these mysteries endlessly here, but now we know factual reasons from the Designers themselves.

You guys rock! that article is pure gold as far as I'm concerned. I keep going back to that article and reading small tidbits and savour it that way. Seriously cannot wait for the MWF prototype to roll out. Haven't looked forward to any airplane as much as I'm looking forward to it and the LCA Navy Mk2.

Which brings me to the second point- you guys have got to get a LCA Navy Mk2 article as well. So many independent design choices have been made there that it deserves a complete separate analysis as well, with plenty of pics if possible.

Thanks in advance !

[Kartik]

Cool! HAL has a fan following here..

Will just put down some facts and benchmarks

1. The price of RS.463 Cr is a base flyaway cost, no weapons, no training infra, no amortisation of development cost. Development cost has been funded by MoD up to MK1 directly. Not sure if it came from IAF budget or from DRDO budget.

2. FA 50, JF17, Gripen C which have similar payloads, speed, endurance with GE404 engines are around USD25 to 40 million each with no weaponry and no training and infra. The JF17 has serious radar and avionics upgrade needs, so may not be a great comparison. The air show which was a precursor to a light combat aircraft buy, in Malaysia last quarter saw numbers of USD 25-35 mm.

3. At USD 65 to 70 mm a pop, you are close to clean costs for F16/Block 60, Gripen E etc. These aircraft have better payload and endurance (nearly 40 to 50%) and better performance.

Facts and benchmarks require you to provide authentic and verifiable sources for the info. You have provided no sources to the highlighted parts. How do you know for instance, what is part of the RFP response that HAL has provided? How do you know whether or not it includes the cost of simulators and the cost of DEVELOPING those sims?

And your data is wrong. For instance, your Gripen C benchmark is WAY OFF. The Gripen C/D is more in the $65-70 million range flyaway cost. Not program cost or acquisition cost, which is more in the $100-120 million range. Google for how much it was going to possibly cost Botswana for getting 8 Gripen C/D fighters- around $1.7 billion.

JF-17 is only in the same weight class but a generation behind in terms of technology. An all-alloy structure built and assembled using older techniques will cost less than a fighter that has as much composite content as the Tejas. It is not as sophisticated as the Tejas. Simply comparing payload, speed and weaponry mean that you could the MiG-21 to the mix and it has an even higher top speed than the Tejas, JF-17 and FA-50. So is it smart to compare it's price to that of the other 3?

And please provide sources for the costs of the Gripen E and F-16 V/Block 70. Not some figure pulled out of the thin air by you.

[Dileep]

About RCS: The "size doesn't matter" is a theoretical notion, valid only for a) Perfectly flat and smooth surface and b) oriented at an angle different from normal to the radar line of sight. Practically, there will be some return from the surface imperfections and deviations from flatness and the (unavoidable) edges. So, size DOES matter in reality. I would venture that the RCS should increase proportional to the 'perimeter', since edges contribute the most to the reflections.

About composites: Imagine glass with respect to light. Glass is transparent, but you can readily see it in air, right? Of course, it is 'less visible' from a bright metal object. The situation is similar. Also, you should remember that the stuff within the skin are all made of a lot of metal. So, being simply 'transparent' will not help either.

[Jay]

Cool! HAL has a fan following here..

Will just put down some facts and benchmarks


No one from HAL was harmed in the making of this post

Saar, did you pull all these "facts" out of your musharraf? No wonder it stinks. Everything you said in your post was discussed in 'triplicate' on this forum. If you can get off your ''high gadha" and read them before scattering "warm air" you will be doing everyone, and yourself a favor.

[JayS]

About RCS: The "size doesn't matter" is a theoretical notion, valid only for a) Perfectly flat and smooth surface and b) oriented at an angle different from normal to the radar line of sight. Practically, there will be some return from the surface imperfections and deviations from flatness and the (unavoidable) edges. So, size DOES matter in reality. I would venture that the RCS should increase proportional to the 'perimeter', since edges contribute the most to the reflections.

About composites: Imagine glass with respect to light. Glass is transparent, but you can readily see it in air, right? Of course, it is 'less visible' from a bright metal object. The situation is similar. Also, you should remember that the stuff within the skin are all made of a lot of metal. So, being simply 'transparent' will not help either.

In fact, Ben Rich mentioned in his book that, Skunk works tried a completely transparent skin concept long time back in 50s. The engine would light up like Christmas tree on Radar with ten times higher RCS than what the Aircraft would have had normally. And there is nothing you can do about the engine. Similarly, for cockpit, if the canopy is not treated for RCS reduction, the cockpit itself is sufficient to completely undo large chunk of the advantage of a stealthy design.

Thanks for the clarification, saar, on the size and RCS issue.

[yensoy]

About RCS: The "size doesn't matter" is a theoretical notion, valid only for a) Perfectly flat and smooth surface and b) oriented at an angle different from normal to the radar line of sight. Practically, there will be some return from the surface imperfections and deviations from flatness and the (unavoidable) edges. So, size DOES matter in reality. I would venture that the RCS should increase proportional to the 'perimeter', since edges contribute the most to the reflections.

The wiki entry for F-117 is very enlightening in this regard. The original Russian work claiming/proving that RCS is only determined by edges, and has little bearing on size is referenced; the F-117 aircraft has RCS of 0.001m^2 which is equivalent to roughly a 3cm x 3cm reflector. I interpret this as all surface imperfections together amount to a reflection of what would be produced by a perfect reflector of 3cm x 3cm all most angles; excepting the singularities where reflections are concentrated. Those kinds of singularities will show up as sudden flashes on the radar which can't be tracked because of their ephemeral nature and might end up getting filtered out as noise.

[JayS]

http://delhidefencereview.com/2019/02/2 ... t-fighter/

Updated second part. We added a few interesting points on LCA wing design. Do read to know why Tejas has lower sweep on inboard section or why the inboard section looks like it has anhedral (but it doesn't). We have had discussed these mysteries endlessly here, but now we know factual reasons from the Designers themselves.

You guys rock! that article is pure gold as far as I'm concerned. I keep going back to that article and reading small tidbits and savour it that way. Seriously cannot wait for the MWF prototype to roll out. Haven't looked forward to any airplane as much as I'm looking forward to it and the LCA Navy Mk2.

Which brings me to the second point- you guys have got to get a LCA Navy Mk2 article as well. So many independent design choices have been made there that it deserves a complete separate analysis as well, with plenty of pics if possible.

Thanks in advance !

work in progress. Too slow at my end.

Just to point out, now we can imagine, what it exactly meant when its said that the canard configuration had only marginal benefits over the double delta wing, which is a simpler and hence obvious choice. A pure delta with canard would end up in much smaller wing area, albeit at higher slope of C_L_alpha curve. Double delta would have lower C_L for given AoA, but its much higher wing area would compensate for that and overall lift force would still be the same more or less.

[Haridas]

About RCS: The "size doesn't matter" is a theoretical notion, valid only for a) Perfectly flat and smooth surface and b) oriented at an angle different from normal to the radar line of sight. Practically, there will be some return from the surface imperfections and deviations from flatness and the (unavoidable) edges. So, size DOES matter in reality. I would venture that the RCS should increase proportional to the 'perimeter', since edges contribute the most to the reflections..

Quite ironic that most people who talk of RCS have not seen scaler/vector Network Analyzer in their life.

Secondly the armchair RCS experts comparing one LO aircraft with another don't know if the military asks for all aspect RCS figure or sectoral? Any query on the subject must first start from answering and understanding this question.

About composites: Imagine glass with respect to light. Glass is transparent, but you can readily see it in air, right? Of course, it is 'less visible' from a bright metal object. The situation is similar. Also, you should remember that the stuff within the skin are all made of a lot of metal. So, being simply 'transparent' will not help either

You punchured the enthusiasm of composite wing RCS vigyatha/scientists !

[Haridas]

Just to point out, now we can imagine, what it exactly meant when its said that the canard configuration had only marginal benefits over the double delta wing, which is a simpler and hence obvious choice. A pure delta with canard would end up in much smaller wing area, albeit at higher slope of C_L_alpha curve. Double delta would have lower C_L for given AoA, but its much higher wing area would compensate for that and overall lift force would still be the same more or less.

Not to mention higher internal volume.

[Haridas]

Quite ironic that most people who talk of RCS have not seen scaler/vector Network Analyzer in their life.

I once was building my own anachoic chamber with special stuff absorbing surface, and calibrating it for required system accuracy, it gave deep quantitative insight to RF reflections in a near perfect materials & environment, what to speak of ruggedized military combat aircraft with smooth aerodynamic surfaces !

[JayS]

Just to point out, now we can imagine, what it exactly meant when its said that the canard configuration had only marginal benefits over the double delta wing, which is a simpler and hence obvious choice. A pure delta with canard would end up in much smaller wing area, albeit at higher slope of C_L_alpha curve. Double delta would have lower C_L for given AoA, but its much higher wing area would compensate for that and overall lift force would still be the same more or less.

Not to mention higher internal volume.

And better structural efficiency or lighter wing structure with longer chord at wing fuselage interface.

[suryag]

Gurus very curious picture in the link below of Tejas, I see 5 bombs dropping never seen a layout which had multi bombs like this loaded , which exercise was this from


https://www.hindustantimes.com/india-ne ... uIfNK.html

[nachiket]

Gurus very curious picture in the link below of Tejas, I see 5 bombs dropping never seen a layout which had multi bombs like this loaded , which exercise was this from


https://www.hindustantimes.com/india-ne ... uIfNK.html

That is a Mirage 2000 saar.

[Rakesh]

Surya Saar, come on!

[suryag]

Yeah yeah make fun of my vision but as Someone said more than my eyes it is the mind which sees what it wants to

[kit]

About RCS: The "size doesn't matter" is a theoretical notion, valid only for a) Perfectly flat and smooth surface and b) oriented at an angle different from normal to the radar line of sight. Practically, there will be some return from the surface imperfections and deviations from flatness and the (unavoidable) edges. So, size DOES matter in reality. I would venture that the RCS should increase proportional to the 'perimeter', since edges contribute the most to the reflections.

About composites: Imagine glass with respect to light. Glass is transparent, but you can readily see it in air, right? Of course, it is 'less visible' from a bright metal object. The situation is similar. Also, you should remember that the stuff within the skin are all made of a lot of metal. So, being simply 'transparent' will not help either.

out of curiosity do all composites behave the same way as you describe ? as someone described a stealth skin " The F-22’s skin requires coating with a microwave attenuating material to minimize RCS, while the F-35’s skin is microwave attenuating in very large part by itself without coating. It is coated, but more in context like puting gravy on the prime rib, rather than being entirely necessary. However, the coating is definitely needed on the small areas that are finished in metal, or some material other than the extremely hard-surfaced bismaleimide/carbon fibre composite that skins the great majority of the F-35’s exterior.

The two aircraft have different coating material, but some F-22s & even some non-stealth aircraft are being coated with the F-35′s more durable material. The F-35’s skin & its finish are more technically advanced (time does do that) & much more resistant to damage "

[Dileep]

"Metals" being good electric conductors, behaves essentially the same across irrespective of type. Composites, being non conductors behaves differently depending upon the various parameters. But essentially, a non conducting barrier that is thin compared to the wavelength of the radio wave will be transparent to the wave. However, there will be the equivalent of 'refraction' and the effect will depend upon the dielectric constant of the material. (This is why the design of radomes becomes black magic, and the Cobham radome gave considerable better performance than the local designed radome)

To absorb radio waves, you need to offer a conducting medium. So, all radar absorbing coatings are conductive coatings. If you manage to embed this conducting property within the composite (carbon fibers are conductive for example) then the composite will absorb radio waves.

One more thing. To properly absorb the radio waves, the impedance seen by the wave should be equal to that of free space. That is why a metal sheet reflects the wave instead of absorbing it. Let me also mention that the "impedance seen by the wave" depend upon the shape of the object, the angle of the wave, the wave length etc.

It's .... Complicated....

[Haridas]

^^^ it's indeed very complicated. If one likes Maxwell eqution and loves material science, only then it is easier to understand.

[gaurav.p]

https://twitter.com/indiandefence11/sta ... 5389547520

An Indian Air Force Boeing C-17 Globemaster III unloading a HAL/ADA Tejas Mk.1 Multirole Fighter Aircraft of the Indian Air Force

Wondering why a Tejas is being delivered by a C17? Delivery from HAL to Sulur happens this way? I thought someone would fly them to Sulur.

[Kakarat]

^This is a old image of TD-1 being taken for Republic Day parade

[Cybaru]

Ground demo aircraft, not meant for flying ops?

[Kartik]

No that is a real aircraft. But as mentioned above it was an old TD prototype that was being taken to New Delhi for Republic Day display purpose.

[jaysimha]

SOCIAL MEDIA COVERAGE OF LIMA2019 AT LANGKAWI, MALAYSIA
FROM 26 MAR – 30 MAR 19 http://indianairforce.nic.in/content/lima-2019

[JayS]

^This is a old image of TD-1 being taken for Republic Day parade

Did they repaint TD-1 later..? It was white to start with.

[Kakarat]

Yes and used it as Republic Day parade 2014 display mounted on a trailer and they made it look like SP version aircraft.
This was after the aircraft was grounded

[navneeet]

And now it sits majestically outside the DRDO Bhavan

[suryag]

heartening to see Nambiar sir and Badauria sir reaching the top. They were the initial air warriors helping Tejas out during the turbulent period between 2004-2008. Hope they can use their high offices to influence to further accelerate production from HAL

[Bhaskar_T]

Gurus, is Tejas going to Paris Air Show this year scheduled from 17-23 June 2019? After Bahrain and KualaLumpur, would be great if Tejas says Hello to Paris too.

There is chatter (no confirmed news) on Twitter that JF-17 is likely to visit Paris Air Show this year. ( I recall JF-17 had a Paris debut in 2015).

[ashishvikas]

Boost to desi missions as Air Marshal Bhadauria takes charge as Vice Chief
https://english.manoramaonline.com/news ... chief.html