LCA: News & Discussions - October 2016

[Karan M]

There is always the possibility that they are considering it and I am misinformed. But I know that it is certainly not a priority item as of now. I also know that IAF hasn't asked for it either.

May be I am sitting with the wrong circle of friends, pilots included. But that 1:1 ratio is not from me. That is what most of them agree with. They do not believe in having most pylons taken over by BVR missiles and having nothing to fight with in close combat situations.

P.S. I do have friends who fly the latest 4.5 generation crafts, but none who fly the 5th. I don't know how the equations change there.

I hope that group is not IAF because the above reasoning is very dependent on the missiles being near their "advertised" Pk which is very unlikely in wartime (rough handling) plus all sorts of other factors (ECM, tactics) etc. The end result is you have to have more BVR missiles before going WVR. In WVR "everyone is at the same place", thanks to HMS + HOBS missiles. Why even go there if you have AESA and BVR salvos?
This is also the reason why we need Astra up and running fast, because large stocks of BVR missiles are now daal chawal and part and parcel of the conflict

[Karan M]

That is a serious mistake (IMHO) on their part given the issues with per missile reliability for most worldclass missiles and the need to launch multiple missiles per target for decent Pk.

From what little I read about modern BVR tactics with active seeker missiles is the aircraft that detects an enemy first will increase speed, climb up and launch AAMs to give them best possible kinematics and then bank away to avoid any incoming missiles. That's where F-22 has advantage with its VLO and super-cruise. And then repeat that process until WVR occurs.

The other technique shown by Gripen is buddy BVR where one illuminates the target with its radar while the other shoots BVR silently from another location.

However, in all of wars fought till now BVR kills have occurred in 30-40km max ranges. Part of had to do with engagement policies adopted at those times. With the ranges of BVR missiles increasing to over 100km, we will likely see more long range shoot-offs (and probably less kill ratio per missile).

The aircraft which detects first and shoots first without being detected has the advantage. IMHO, this is where LPI equipped fighters had a huge advantage versus prior gen aircraft with older RWRs. Newer RWRs with LPI detection capability will take away some of these advantages, but the advantage as shown by USN of weapons grade tracks from AEW&C to fighters will remain and as you said the buddy designation system.

[srai]

There is always the possibility that they are considering it and I am misinformed. But I know that it is certainly not a priority item as of now. I also know that IAF hasn't asked for it either.

May be I am sitting with the wrong circle of friends, pilots included. But that 1:1 ratio is not from me. That is what most of them agree with. They do not believe in having most pylons taken over by BVR missiles and having nothing to fight with in close combat situations.

P.S. I do have friends who fly the latest 4.5 generation crafts, but none who fly the 5th. I don't know how the equations change there.

I hope that group is not IAF because the above reasoning is very dependent on the missiles being near their "advertised" Pk which is very unlikely in wartime (rough handling) plus all sorts of other factors (ECM, tactics) etc. The end result is you have to have more BVR missiles before going WVR. In WVR "everyone is at the same place", thanks to HMS + HOBS missiles. Why even go there if you have AESA and BVR salvos?
This is also the reason why we need Astra up and running fast, because large stocks of BVR missiles are now daal chawal and part and parcel of the conflict

In the past, expensive weapons like LGB, ASM and BVR AAM were "rationed". Holdings were few.

Nowadays, we are hearing of the IAF wanting to order LR PGM 1000/year. Times are changing.

[vina]

The Harrier GR 9 had four hard points per wing, including an outer hardpoint stressed to carry Paveway IV weighing 500 lbs 225 kg, that is almost double the weight of Derby.

PRILLY ANT . Harrier II == Harrier I , F 18 E/F == F18 A/B/C/D ..
So, you can change the wing, you can change the fuselage , you can change every damn thing, and add a very small "I" after the original and make it "II" and then we can conclude and troll that , that "I" also could be fitted with 4 hard points, and they could carry whatever and indeed I and II are the same plane.

Of course, George Bush 41 == George Bush 43 (nice na?) and hence George Bush 41 was one of the physically fittest presidents ever and could run 5 miles in 20 minutes.

Can the Tejas can carry a 500 lbs / 225 kg bomb on its outer wing hardpoint?

After the R60 to R73 fiasco (thanks to the IAF) the outer wing hard point of the Tejas is INDEED stressed to 250Kg (if you have been actually reading BRF long enough, you would have known this)

So the basic premise of outer hardpoint can carry light missiles like R-60 is incorrect, and it was the Tejas designer's fault of not keeping any growth margin in the outer wing hardpoint.

Adding new missiles to replace new ones was done for MiG-21, possibly MiG-23 and Sea Harrier without the rona-dhona of,"oh, my outer wing hardpoint was designed only for 43 kg R-60. Very bad user upgrading missiles and changing specs."

Yes. How sweet. Some is going to decide that they are going to have a 6X higher load than what they specified (indeed, the Tejas overall payload should be 24Ts, and not the 4T as per the spec .. and if they didn't cater to that, they were bad designers)..

Of course, I and II are just numbers. British Aerospace Harrier II Harrier II Development

[Karan M]

Regarding USAF vs. Chinese fighters, it is difficult to say. Which of the two parties are on the longer flight stretch. That will dictate the tactics of engagement. Regarding taking on a swarm of Chinese fighters, many believe that given the quality advantage of both USAF aircraft and missiles over their Chinese counterparts, the former would do better to carry more missiles per aircraft to offset the numerical disadvantage vis-a-vis aircraft. This is also based on the fact that most modern aircraft (including the Chinese) won't be downed by BVR missiles at long range. The BVR missile puts them in a compromised position at the "merge", and the CCM will be used to finish off the job. As you might already know, even with fifth gen aircraft boasting x:1 killing ratio vis-a-vis fourth gen adversaries, it is derived out of on y sorties where y if typically >= x/2.

With DRFM jammers the quality aspect may no longer hold true. The quality aspect comes into play at close range (the advanced countries have the edge in IIR missiles) but even otherwise with a bunch of aircraft all mixing up at close range, even a F-22 may be downed by a Python-3 from a J-7. So BVR is better, but for successful BVR you may have to salvo 2-3 missiles per target.

[srai]

How come a Maruti Suzuki 800 can carry my checked-in baggage and carry-on but a Ferrari only has a piddly compartment for a carry-on??? Look a Maruti Suzuki 800 you can add an overhead bin as well. So I can carry not one checked-in baggage but three! Ferrari bad designers

[shiv]

The aircraft which detects first and shoots first without being detected has the advantage.

Without meaning to be disrespectful of French pilots - the first guy who shoots without a snIFF of IFF may also be declared winner so long as the tactics are "more flexible"

I say that in the context of:

Regarding BVR tactics of the IAF, it went through major revisions post Ex-Garuda-1 in 2003.

viewtopic.php?t=333#p31547

...
IAF pilots tell me French tactics in the BVR regime are different and more flexible than ours
...

[shiv]

Nowadays, we are hearing of the IAF wanting to order LR PGM 1000/year. Times are changing.

Completely off topic - but towards the end of my Tawang border infra video there is a short virtual flight that shows what sort of terrain targets Chinese targets are situated in. I really think standoff glide bombs (Garuda/Garuthma?) would be a great asset here. However I would be curious about the trajectory/glide path if launched from say 10 km altitude towards targets that are at 3-4 km (10-13000 feet) altitudes. I expect these will also be tested given our experience in Kargil.

[tsarkar]

Can the Tejas can carry a 500 lbs / 225 kg bomb on its outer wing hardpoint?

After the R60 to R73 fiasco (thanks to the IAF) the outer wing hard point of the Tejas is INDEED stressed to 250Kg (if you have been actually reading BRF long enough, you would have known this)

No, I do not believe what is written here at all because people like you lie to suit their convenience.

I go by what has been certified. As per ADA itself, the outer hardpoint is still certified only for CC AAM.

http://www.tejas.gov.in/specifications/weapons.html

So let ADA certify the hardpoint by CEMILAC and then I'll believe. After all, India is a meritocracy, and we give tests from kindergarten onwards.

And the outer wing hardpoint is stressed to 150 kg and NOT 250 kg.



I know you think Tejas is like Rahul Gandhi perfect at birth entitled to rule India as his grandmother's gift and its the bloody IAF that has to live with 43 kg R-60 throughout Tejas product lifecycle.

So the basic premise of outer hardpoint can carry light missiles like R-60 is incorrect, and it was the Tejas designer's fault of not keeping any growth margin in the outer wing hardpoint.

Adding new missiles to replace new ones was done for MiG-21, possibly MiG-23 and Sea Harrier without the rona-dhona of,"oh, my outer wing hardpoint was designed only for 43 kg R-60. Very bad user upgrading missiles and changing specs."

Yes. How sweet. Some is going to decide that they are going to have a 6X higher load than what they specified (indeed, the Tejas overall payload should be 24Ts, and not the 4T as per the spec .. and if they didn't cater to that, they were bad designers)

More madarssa mathematics fudging here. R-60 weighs 43.5 kg. R-73E weighs 105 kg as does Python 5. That is 2.4x R-60 weight. Not 6x. And no one asked for the overall design specifications to be changed. That's your lie to suit your convenience.

Anyways, I just laid the facts on the table on the need and ease of missile upgrade on aircraft. The Sea Harrier saw 3 AAMs in its life and was upgraded without design changes.

You may believe in whatever you want to. But the world will be realistic. Don't keep growth margins. User will choose aircraft easier to add missiles to without re-design.

[tsarkar]

How come a Maruti Suzuki 800 can carry my checked-in baggage and carry-on but a Ferrari only has a piddly compartment for a carry-on??? Look a Maruti Suzuki 800 you can add an overhead bin as well. So I can carry not one checked-in baggage but three! Ferrari bad designers

Depends on the intended role.

The MiG-25R carried zero weapons but had high performance. Ferrari & MiG-25R were designed for performance, not carry family & luggage.

Maruti 800 and Tejas are designed to carry 4 people with normal luggage and to carry normal baggage, if the boot needs redesign, then we have a problem

Anyways, I personally like the Tejas and fervently hope designers make Mk2 perform well enough for aircraft carriers.

I hate imports too - I dont want my balls in someone else's hands to extract or squeeze as they wish.

What I don't like is Madarssa Mathematics and Lahori Logic to substitute reason.

Face the problem for what it is and resolve it. Conspiracy theories will take you no where.

And someone else (Dileep?) also confirmed a few pages earlier what I've been saying all along - we're facing very normal development issues.

[srai]

^^^

150kg not enough for a "normal" luggage

[tsarkar]

^^^150kg not enough for a "normal" luggage

Normal luggage is only 105 kg Maybe 118 kg when wife packs extra formals for the Derby

[Zynda]

^^tsarkarji, what do you think should be the upper weight limit for which LCA wing tip hard points should have been designed?

[srai]

^^^150kg not enough for a "normal" luggage

Normal luggage is only 105 kg Maybe 118 kg when wife packs extra formals for the Derby

So what was the point? 150kg is enough for current generation of BVR/CCMs. Are you saying you want even more?

[Singha]

The usmc harrier is a mud mover redesign of original british design. Sure it can fly like grand piano with all those pylons filled up but see how it performs.

Tejas was built for acm with second strike role and weight saving was a major goal.

Ask a f15e or su30 driver the flight envelope with the showpiece load of 30 bombs hung back to the tailpipe

[tsarkar]

So what was the point? 150kg is enough for current generation of BVR/CCMs. Are you saying you want even more?

I meant 150 kg is good enough, and accommodates a BVR Derby weighing 118 kg as well

^^tsarkarji, what do you think should be the upper weight limit for which LCA wing tip hard points should have been designed?

Simple - India has connects with major missile developers in the world, and it would be easy to know the all up weights of missile + pylon under development. Choose a weight limit that accommodates most under development plus add a 20% margin. That way you've some insurance against obsolescence.

MICA weighs 112 kg Derby weighs 118 kg R-73E weighs 105 kg Python 105 kg ASRAAM 88 kg.

Adding pylon weight + margins, 150 kg is the optimum capacity for that hardpoint. This is exactly what we did in the second iteration.

[brar_w]

Normal luggage is only 105 kg Maybe 118 kg when wife packs extra formals for the Derby

So what was the point? 150kg is enough for current generation of BVR/CCMs. Are you saying you want even more?

Depends upon a host of factors. There is about a 25% weight penalty currently associated with switching to a VFDR system so if that is the path the Astra MK2 goes than it should be around the Meteor mass if they retain the industry standard large MRAAM (AMRAAM, R-77, Meteor) characteristics.

[ramana]

tsarkar, Your posts are very informative. but get colored with needless rhetoric. Can you refrain from needless flame baits of LL and MM?

Thanks,
V/R

ramana


Good example

Simple - India has connects with major missile developers in the world, and it would be easy to know the all up weights of missile + pylon under development. Choose a weight limit that accommodates most under development plus add a 20% margin. That way you've some insurance against obsolescence.

MICA weighs 112 kg Derby weighs 118 kg R-73E weighs 105 kg Python 105 kg ASRAAM 88 kg.

{Average = 105.6 Kg and S.D = 11.25 kg. Therefore 4 Sigma gives 150 kg!!!}

Adding pylon weight + margins, 150 kg is the optimum capacity for that hard point. This is exactly what we did in the second iteration.

[shiv]

All said and done - and my intention is not to take issue with anyone over anything that may have been said - but if a plane or a pylon cannot take a particular load then there is always the option of designing a new munition/mod to adapt to the pylon/plane. Take Mountain to Mahomet logic.

Examples are the creation of SDB to fit internal bays American copies of J-20 (like F-35) (I know I know.. ). Brahmos air launched weight shaving.

[Zynda]

Simple - India has connects with major missile developers in the world, and it would be easy to know the all up weights of missile + pylon under development. Choose a weight limit that accommodates most under development plus add a 20% margin. That way you've some insurance against obsolescence.

MICA weighs 112 kg Derby weighs 118 kg R-73E weighs 105 kg Python 105 kg ASRAAM 88 kg.

Adding pylon weight + margins, 150 kg is the optimum capacity for that hardpoint. This is exactly what we did in the second iteration.

Thanks. I still think that it is the user that has to supply weapon load outs for different mission profiles to the design agency. However, I dunno when R-73 was inducted in to service with IAF, but LCA designers should have anticipated at least a load out involving R-73. I suspect initial design was frozen even before R-73 was in-service with IAF. Probably IAF got more involved during 2nd round of design iterations and supplied ADA with better design inputs and hence heavier weight rating.

P.S: Just FYI. The wing tips hard points of Gripen NG are designed for 110 Kg rating

[vina]

Normal luggage is only 105 kg Maybe 118 kg when wife packs extra formals for the Derby

So what was the point? 150kg is enough for current generation of BVR/CCMs. Are you saying you want even more?

There. See, as usual, the B/S artiste B/Sed when you asked a straight question and gave a 20% margin . Well, a 20% margin as he wanted on a R60 class (the original Mig 21 weapons fit that was specified for the LCA) will leave you short on the new fit.

It is like this. It was I, yes, Your's Truly, who connected the dots on this thread and said that the reason why the Carriage and Separation trials were not happening was because with the Bison upgrade that was done (Yes, Mig 21 Bissun, Is NOT == Mig 21 Kissun.. Bissun != Kissun, Bissun was an MLU and included significant structural rework as well, it cannot be just fitting a R 73 or anything in a original Mig 21 Kissun hull and wing) , and that because of the upgraded weapons specs, the LCA TD wings lacked the Aeroelastic stiffness for the new fit and said that there had to be a wing redesign and this is atleast a 1 year delay. This was confirmed by a structural engineer who had worked at ADA , who replied to my post and said, yes, there was a marginal shortfall in torsional rigidity and a redesign did happen and it was a 1 year delay. It was only after this, the DDM and the other media picked up this R60/R73 story and I think it even had a parliamentary question on it and it got tom tommed around in other blogs and stuff.

That apart, as an exercise in doing an "analysis" , look around to see WHAT would have been the upgraded specs, once the IAF knew that it's fat was on the fire. They would have seriously looked around. Yes, all the IR A2A missiles were in the 150Kg class and roughly would have specified a 200 kg load on the wing tips. But if you looked deeper, the F16s and others in their MLU were mounting AMRAAM class missiles in the wing tips. That tells you that the loads specified would be around 250Kg (the AMRAAM class of BVR) and that is roughly what the IAF would have done as well.

Now how would you seek data to back up the 250kg hypothesis. It is like this. HAL promised to put a SPJ (around 200 odd kg) on the wing , without any loss of pylons or significant strike payload. And where can they do that ? Only in the wing tips. A mid board or inner pylon would see a significant loss in payload.

Again, look at the pictures Indranil posted in the earlier page on config studies on the SPJ (I am posting that again)

.
If they were doing this WITHOUT any wing redesign (that would require time and testing effort), and within the timeframe of the 1A, for both config 3 and config 4, the wing tip HAS to have a rating of at least 100 + 200 kg , if you go with the lightest IR missile around. Between 3 and 4, Config 4 seems more plausible, because, you have margin to go with a higher wt missile on the wing tip (i.e. 2X no of missiles hit the upper load rating and hence more flexibility in missile choice).

If you follow the B/S about 20% margin on the existing missile wt , no way in hell, you can have a dual carriage pylon for an IR AAM in the wing tip, which the LCA obviously has and is being showcased and indeed the entire MK1A and acceptance of even the Mk1 by the IAF is predicated on that.

This kind of analysis is not rocket science, but just requires some basic common sense and obviously knowledge of the fundamentals and ability to think straight on facts.

PS: Just saw Brar_W 's post on this after I hit the submit. He has it right. They would have sized it to an AMRAAM class fit at the wing tips , especially so when they are planning to put a SPJ there.

[negi]

Onus of providing a requirement is never on the user ; whoever is in product development knows this pretty clear users are like a kid they cry when they need something onus to interpret what they mean or really need is on the chap who makes the product ; anyone who thinks otherwise has never delivered a successful product . When user knows what they need then it is no longer a product it's a service. Not that this means it is all DRDO's fault Tejas is much more complex and hence it is all the more important to not pass such idealistic statements.

[Marten]

Negi, that holds true if you have multiple customers. In this case, can't apply this road map without the complete involvement of the sole user. Whatever the IAF wants, DRDO-HAL must deliver. They must solicit requirements, delivered vide ASQRs. They can plan but cannot unilaterally add to a product that is already full to the brim. SOPs and RFAs exist for a reason.

[negi]

Boss one customer or multiple it does not matter ; no one outside of the team who wishes to deliver the product can articulate requirements to a level of detail which describe a ship-able product . It is a fundamental fact . That is why when one builds something the features are a function of time what one delivers this year could be obsolete next year and that is why if one knows in advance that product will take more time you deliver more to keep it relevant . I am not talking about anything product development specific I am merely talking common sense.

[SaiK]

and there is requirement engineering that is overlooked. it requires all stake-holders participate including the designer. a user may not be able to tell his wants, but it can be arrived at in many ways. there are engineering methods for this [it is easy here because, there are IAF reqs, SOPS, existing products in use, and enemy products on the radar, etc]. this ain't software engineering purely speaking.

[VKumar]

One thought I had about the recoil of the gsh on Tejas. If Tejas cannot handle the recoil, will it be sensible to fit a gun with lesser recoil, at least till the recoil can be handled. It will at the least equip Tejas with a gun.

[Vivek K]

Bhai sahib, there are pan wallah reports (Indranil's post) that gun testing on LCA is going well. Ground tests seemed to go well. What is being discussed is a hypothetical situation or like Hakim ji would say - intellectual masturbation. Hang on to your horses. LCA is the best India has and will have. And it will "need to be" produced in numbers.

[ramana]

vina, Same suggestion that I gave tsarkar applies to you too.

I would like us to not personalize posts in the open forums from now on.

ramana

[JayS]

We've ample experience with BVR or CCAAM dual racks, given that original Sea Harriers came with dual racks for Magic-1 that were upgraded to Magic-2 and finally upgraded to Derby.

A small data point - when the heavier Derby was added to LUSH, there was no rona-dhona on wing re-design.

The Harrier is a small plane limited by its unique engine, no extensive use of composites, yet it had sufficient design margins to accommodate a heavier missile without re-design / re-build.

Now I don't know much about Harrier jets beyond the general knowledge from some documentaries. But casual googling gives me few pictures of Original Harrier GR1/3 with rocket pods and bombs mounted on the outboard pylon.







Caption for this one says:

A Hawker Harrier GR.1A loaned to the U.S. Marine Corps attack squadron VMA-513 (as WF-12) for trials in 1971 (RAF serial XV742). It was later returned to the Royal Air Force and in 1982 modified to the GR.3 standard. It crashed at Holbeach range, Lincolnshire (UK), on 28 October 1983 while in service with No. 233 Operational Conversion Unit (OCU), RAF.

To me it looks like the outboard pylons were designed right from starting for a much higher load than a AAM missile or two. As such with those outrigger wheels seating at the very tip, why are we even surprized that the outboard pylon can take up quite a lot of weight...?

Also I do not quite understand why you posted those GR9 version pics. Its a completely redesigned wing for AV8B, and if you design it for 250kg load then you can obviously carry that much load. But where does it say that Original AV8A or even AV8B wing was designed keeping in mind only llightweight CCMs from that era but there was sos much design margin kept that they could carry 500lbs bombs without any need to tweak to the wing..?? Harrier simple looks like was always designed for bombs on the outboard pylon both the generations.

[JayS]

Incorrect assertion to draw based on what info you posted, unless you have a specific info saying so. Else there can be perfectly valid engineering arguments made to show otherwise.

I stand by my PoV that IAF & IN added new missiles as older ones became obsolete, and their aircraft, whether MiG-21 or Sea Harrier, had hardpoints with adequate margins to allow them do so without major re-design as required for Tejas outer wing hard point.

I would be happy to learn incase you have any alternate / additional facts and logic to my above PoV.

Please show if you can, a reference saying Harrier's outboard pylons were *designed only for CCM* of the 1970's era, but could easily take not only new CCM but two AAM on the same pylon without redesign. That would be a fact showing your POV is correct.

Leaving all the factual knowledge aside and without having any knowledge about any aircraft whatsoever, just by knowing how the structural design methodology has evolved over last 50yrs, one can argue that the Harrier was over-designed for given load. That is with the 1960's methodology it was designed say for 100kg, but since the design methodology was less mature, the design actually was more than necessary. Later with improved methodology the OEM could certify the same pylons for higher loads cutting down on the conservatism in the initial design. Now the same pylon is certified to carry say 200kg load without any need for redesign. I have seen such correction in methodology for structural design personally in one of our own product. And I know other such examples from Aerospace industry, both in Metals and composites. You know how F15 seems to have never ending airframe life..? Because they were over designed. Would the designer over designed the aircrafts so much that they can have 3 or 4 times intended life at the height of cold war, if they knew with 99% confidence that they are over designing..?? Obviously not.

If you do not have factual data showing Harrier designers indeed deliberately kept margin for growth in CCM weights, you cannot ascertain they did it merely by looking at the fact that the pylons could take significantly more load than the original requirement (In fact to me it seems the outboard pylons were designed for 500lb bombs/rocket pods at least right from the start). That could just be a lucky coincidence. Thus I said what I said.

The Factor of Safety that is being used in design has been reducing over the years. Its true even for HAL. If you hear what HTT-40 Dy. PM had to say in one of his seminars, he clearly said that HAL has been over designing wings previously but now they have cut down the conservatism to such an extent that the wings designed for 150% Ultimate load now fails at 168% in case of HTT-40, where as it used to be >190% in past. (Ideally the wing should fail at 151%..!!) What this tells you LCA's structural design is somewhat inefficient. Even ADA/HAL knows this. And during AI2017, from what I heard from an ADA employee manning the booth there, HAL could reduce 800kg after all. He emphasized its possible. This is only possible if they can reduce weight on entire airframe structure by reducing the conservatism in their design methodology from 1990s. Now that gives us this plausible scenario:
- Initial structural design of LCA was inefficient by a big margin. So to keep the weight under the limits they cut margins wherever possible. Weight margin on the outboard pylon was not considered very critical at that time (We can't just blame engineers, even the deputed IAF officers working with the designers perhaps failed to foresee future of CCMs). Since small reduction in outboard pylon load can have significant effect on entire wing weight, they decided to keep the margin on the outboard pylon minimum.

This is a logical and plausible situation. I don't have factual information to accept or refute it outright. In fact I wouldn't be surprised if ADA tomorrow can certify that same pylon which is certified for 150kg today, to say 175kg without any redesign. Just by improving their simulation methodology or using fatigue testing over a significant loading cycles.

Another example is from the ADE seminar on Tapas-1. THe ADE person presenting the seminar said that worldwide the factor of safety used is 1.25 for MALE design. But ADE has no clue initially what to do, due to lack of knowledge or experience. There were no procedures on what FOS to be accepted for certification and all. They learned through there mistakes. End result, Tapas is overweight. Now they know better and are confident of shaving significant weight in next iteration. OR if they choose to keep the same design, it could sustain more maneuvering loads with more payload, or can give practically infinite life with designed loads. Would you say it was ADE's insightful vision that made this possible..??

[JayS]

Onus of providing a requirement is never on the user ; whoever is in product development knows this pretty clear users are like a kid they cry when they need something onus to interpret what they mean or really need is on the chap who makes the product ; anyone who thinks otherwise has never delivered a successful product . When user knows what they need then it is no longer a product it's a service. Not that this means it is all DRDO's fault Tejas is much more complex and hence it is all the more important to not pass such idealistic statements.

Negi, that holds true if you have multiple customers. In this case, can't apply this road map without the complete involvement of the sole user. Whatever the IAF wants, DRDO-HAL must deliver. They must solicit requirements, delivered vide ASQRs. They can plan but cannot unilaterally add to a product that is already full to the brim. SOPs and RFAs exist for a reason.

The reality lies somewhere between these two extremes - "Customers don't know what they want" and "User defines and drives the product roadmap"

[Zynda]

JayS, I looked up FAR Chap 23 (to which Tapas is being complied with) and it mentions UL FoS as 1.5. I was not able to find to which spec defence UAVs are designed. I would be interested to find out which spec the ADE rep was alluding to which specifies 1.25 FoS.

[JayS]

P.S: Just FYI. The wing tips hard points of Gripen NG are designed for 110 Kg rating

But its wingtip stations as against the outboard pylons on LCA which are away from the wingtips. Apples vs Oranges I would say.

[JayS]

JayS, I looked up FAR Chap 23 (to which Tapas is being complied with) and it mentions UL FoS as 1.5. I was not able to find to which spec defence UAVs are designed. I would be interested to find out which spec the ADE rep was alluding to which specifies 1.25 FoS.

I don't know which standards are used specifically. But that's the whole point. While others have methodologies (some mil standard may be, or something which is not public standards till date, UAVs do come under MTCR so might have been out of bound for us till now, I am not sure though) developed specific for UAVs, ADE had to follow FAR because they didn't have anything else to start with.

Reduced FoS is logical since there are no human lives at stake, so to speak.

Hint - look for USAR 3.0. (UAV Systems Airworthiness Requirements) Looks like new Europian standards for UAV. If you find something let me know.

PS: See UAV thread.

[Karan M]

I stand by my PoV that IAF & IN added new missiles as older ones became obsolete, and their aircraft, whether MiG-21 or Sea Harrier, had hardpoints with adequate margins to allow them do so without major re-design as required for Tejas outer wing hard point.

I would be happy to learn incase you have any alternate / additional facts and logic to my above PoV.

Please show if you can, a reference saying Harrier's outboard pylons were *designed only for CCM* of the 1970's era, but could easily take not only new CCM but two AAM on the same pylon without redesign. That would be a fact showing your POV is correct.

Leaving all the factual knowledge aside and without having any knowledge about any aircraft whatsoever, just by knowing how the structural design methodology has evolved over last 50yrs, one can argue that the Harrier was over-designed for given load. That is with the 1960's methodology it was designed say for 100kg, but since the design methodology was less mature, the design actually was more than necessary. Later with improved methodology the OEM could certify the same pylons for higher loads cutting down on the conservatism in the initial design. Now the same pylon is certified to carry say 200kg load without any need for redesign. I have seen such correction in methodology for structural design personally in one of our own product. And I know other such examples from Aerospace industry, both in Metals and composites. You know how F15 seems to have never ending airframe life..? Because they were over designed. Would the designer over designed the aircrafts so much that they can have 3 or 4 times intended life at the height of cold war, if they knew with 99% confidence that they are over designing..?? Obviously not.

If you do not have factual data showing Harrier designers indeed deliberately kept margin for growth in CCM weights, you cannot ascertain they did it merely by looking at the fact that the pylons could take significantly more load than the original requirement. That could just be a lucky coincidence. Thus I said what I said.

Its absolutely correct the LCA is overengineered. The 8G limitation comes directly from this, the structures are simply too overengineered for the given task and hence the weight adds up and in turn they have to be conservative elsewhere. The landing gear for instance was derived from the Jag per what i remember and HAL overengineered. Many LRUs were likewise.

Why? Same reason why IRON BIRD was run far more than usual levels. Doing it for the first effort and also, they could not ever think of any support for any mistake.
In supply chain management, there is a similar phenomenon called the bullwhip effect.
https://en.wikipedia.org/wiki/Bullwhip_effect
Here the lack of IAF support for key decision points also adds up. The developers either wait for IAF specs to change (fear of extra timeline impact plus customer dissatisfaction) or overengineer because customer is not there to provide practical input (dont worry about x, after all even mirage can only do y). There is a constant rush to get waivers when it becomes apparent the original ASQR were simply impractical or the tradeoffs for certain design choices add up. Ironically, these add more test points and the program is further impacted. Perfect example of IAF joining the program late are ERs - engineering change requests, or RFAs request for action raised by IAF much later into the program in the SP/LSP phase and these are now being iteratively added for Mk1A. On the other side of the spectrum, over involvement but no consistency, Arjun and IA. Every IA General who came or was associated with the program added his own ideas to the program and it was severely affected.

Another example is from the ADE seminar on Tapas-1. THe ADE person presenting the seminar said that worldwide the factor of safety used is 1.25 for MALE design. But ADE has no clue initially what to do, due to lack of knowledge or experience. There were no procedures on what FOS to be accepted for certification and all. They learned through there mistakes. End result, Tapas is overweight. Now they know better and are confident of shaving significant weight in next iteration. OR if they choose to keep the same design, it could sustain more maneuvering loads with more payload, or can give practically infinite life with designed loads. Would you say it was ADE's insightful vision that made this possible..??

He actually makes the point that ADE is designing to FAR-23 which is for passenger aircraft and hence they have a fairly high factor of safety which is suboptimal for UAVs since it adds weight. So ADE took the conservative risk averse route and is now discovering they have overengineered while the foreign UAV vendors are designing to lower factors of safety and hence have lighter airframes with the postive advantage of less engine, fuel requirements and more growth potential for payload.

[Karan M]

BTW here is another unforeseen advantage of the LCA. Given IAF's early insistence on Gnat-MiG-21 style footprint and Mirage/MiG-29 performance and ADAs agreement, the LRUs in the LCA are amongst the most compact and efficient worldwide, this despite being overengineered in many cases. They are really a class apart. A ww vendor told me upfront, that they were still considering ADAs proposal for various items becase they were not sure they could make them at such short notice and this was a vendor who was supplying to Gripen, EF etc. As ADA goes to further steps to optimize LRUs and make them more compact, efficient, it sets us up firmly for AMCA etc. For instance, the multiple processing items in TD for avionic were combined into one OAC for LCA Mk1/Mk1A, and now a further development will be used for Super 30, far superior to comparable Russian systems. So when we hear of delays from x vendor to provide items for LCA keep things in perspectve. Its a real challenge to meet the standards ADA expect.

[srai]

...

Again, look at the pictures Indranil posted in the earlier page on config studies on the SPJ (I am posting that again)

.
If they were doing this WITHOUT any wing redesign (that would require time and testing effort), and within the timeframe of the 1A, for both config 3 and config 4, the wing tip HAS to have a rating of at least 100 + 200 kg , if you go with the lightest IR missile around. Between 3 and 4, Config 4 seems more plausible, because, you have margin to go with a higher wt missile on the wing tip (i.e. 2X no of missiles hit the upper load rating and hence more flexibility in missile choice).

...

===============================
R-73
===============================
100kg - ELTA EL/L-8222
105kg - R-73
------------------
205kg

105kg - R-73
105kg - R-73
------------------
210kg


===============================
Python-5
===============================
100kg - ELTA EL/L-8222
105kg - Python-5
------------------
205kg

105kg - Python-5
105kg - Python-5
------------------
210kg


===============================
Derby
===============================
100kg - ELTA EL/L-8222
118kg - Derby
------------------
218kg

118kg - Derby
118kg - Derby
------------------
236kg


===============================
ASRAAM
===============================
100kg - ELTA EL/L-8222
88kg - ASRAAM
------------------
188kg

88kg - ASRAAM
88kg - ASRAAM
------------------
176kg


===============================
IRIS-T
===============================
100kg - ELTA EL/L-8222
88kg - IRIS-T
------------------
188kg

88kg - IRIS-T
88kg - IRIS-T
------------------
176kg


===============================
AIM-9
===============================
100kg - ELTA EL/L-8222
85kg - AIM-9
------------------
185kg

85kg - AIM-9
85kg - AIM-9
------------------
170kg


===============================
MICA
===============================
100kg - ELTA EL/L-8222
112kg - MICA
------------------
212kg

112kg - MICA
112kg - MICA
------------------
224kg


===============================
Astra
===============================
100kg - ELTA EL/L-8222
154kg - Astra
------------------
254kg

154kg - Astra
154kg - Astra
------------------
308kg


===============================
AIM-120 AMRAAM
===============================
100kg - ELTA EL/L-8222
152kg - AIM-120 AMRAAM
------------------
252kg

152kg - AIM-120 AMRAAM
152kg - AIM-120 AMRAAM
------------------
304kg


===============================
Meteor
===============================
100kg - ELTA EL/L-8222
185kg - Meteor
------------------
285kg

185kg - Meteor
185kg - Meteor
------------------
370kg

[shiv]

Again off topic but can someone educate me on what sort of brain fart was required to put either wingtip tanks OR Sidewinders on the F-104 Widow Maker?

[NRao]

Again off topic but can someone educate me on what sort of brain fart was required to put either wingtip tanks OR Sidewinders on the F-104 Widow Maker?

Germans demanded more fuel capacity (among other things) for the Luftwaffe to buy it. One of the reasons it became the Widow Maker.

Earlier models did not have anything on the wing tip.

[Cain Marko]

Sea Harrier from BR:
The outboard pylons are more than adequate to carry the Derby in terms of weight

Ah, is outboard pylon of Harrier == Outboard Pylon of LCA ?

Harrier Wing Span - 7.6m ---- Tejas Wing Span - 8.2 m

Outboard Pylon of Harrier == MIDBOARD Pylon of LCA.
Outboard Pylon Harrier - 450Kg capability --- MIDBOARD Pylon of LCA - 1000 Kg (I think 1200Kg)
Outrigger Wheel of Harrier === Outboard Pylon of LCA - == 250KG (good for dual pylon IR missiles)

So if we want to see "adequate margins in design " , add a wingtip staton on the Harrier like we see in the Gripen, F16 and SU -30 , put in a 250 Kg missile there and then talk.
Other wise, I will put in a 10 Rack CCM on the Midboard of LCA or, 3 rack of 500 Kg in LCA mid board and claim victory and "strategic upper hand".
Have a nice day.
ps:
Does it matter where you hang stuff from ? Pliss to see .


(this one has answers on why it is so)

Dunno how this works or what it proves, my nephew could easily lift the chairs.... I couldn't though. We are the same height. Seems that age plays some role?