Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

chetak
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby chetak » 25 Oct 2019 22:30

Indranil wrote:This is unfair Chetakji. Naval LCA is unoptimized because it is over designed. But, it is very rugged.

Just before Dussherra they did the first trap. In the following 10 days, they did 20 sorties within ten days. Sometimes, they did 3 sometimes per day. This can not be done on a plane which is not sufficiently rugged.



Indranil ji, you misunderstood the word "marinised" and saar, I did not use the word rugged.

BTW, the trap may not have been a standard Naval deck landing type thumper of a landing. Those are real punishing touchdowns and are more of a controlled crash than a conventional landing. It is not called for at this stage in the tests.

and also, in a deck landing, as soon as the wheels hit the deck, whether the aircraft traps or not, the throttle is always slammed open to its max power position so that the pilot is all set for a go around just in case he did not trap. It's only when he feels the rapid deceleration of a successful trap that he throttles back and never before that.

A carrier deck has multiple arrestor wires to better the chances of a successful first time trap. IIRC, our carriers have 4 wires.


anyway, here's something for you

Some new footage on NLCA's Arrested Recovery in there. Especially the wing mounted camera overlooking the hook engagement is something to drool over for all LCA Fans.

twitter

A special moment of pride and joy Beautifully captured by DEB RANA and Co., The Arrested landing of Naval Prototype of India’s Light Combat Aircraft (LCA, NP-1)


https://twitter.com/Amitraaz/status/1187082696972877824

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Kartik » 25 Oct 2019 23:32

chetak wrote:BTW, the trap may not have been a standard Naval deck landing type thumper of a landing. Those are real punishing touchdowns and are more of a controlled crash than a conventional landing. It is not called for at this stage in the tests.


I didn't get this part. How is a trap on the STBF not a "Standard Naval deck landing type thumper of a landing"? The sink rate is the same, the distance in which the N-LCA is stopped is the same, so what are we missing here? Pitching of the deck? How does that make any big difference? It is the sink rate that counts after all.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby chetak » 25 Oct 2019 23:45

Kartik wrote:
chetak wrote:BTW, the trap may not have been a standard Naval deck landing type thumper of a landing. Those are real punishing touchdowns and are more of a controlled crash than a conventional landing. It is not called for at this stage in the tests.


I didn't get this part. How is a trap on the STBF not a "Standard Naval deck landing type thumper of a landing"? The sink rate is the same, the distance in which the N-LCA is stopped is the same, so what are we missing here? Pitching of the deck? How does that make any big difference? It is the sink rate that counts after all.


Any open source inputs on the sink rate, saar. Just asking only.

the tests normally build up in severity. Again, just asking only because I really could not make out, how many wires were there.

if there was just one wire, then the intention was to snag that single wire with the tail hook so the objective of the test may have been different.

going forward, they will add more variables and complexities to the tests.

As I understand it, the feasibility has been tested/proved and the tests are not completed yet. That may take some time and many more traps.

The stresses on the system will be measured using strain gauges and these sets of traps may not have reached even normal operating stresses of a deck landing because the pilot may not have slammed open the throttle after touchdown. The hook + mountings have to perform consistently up to their max design load and may be a bit beyond that too.

the sink rate, among other forces, may affect the undercarriage primarily but an entirely different set of forces affect the tailhook snagging the wire.

Also, the sink rate is just one of the many variables that come into play for such tests.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Picklu » 26 Oct 2019 00:13

IIRC, the current sink rate on SBTF is around 75% of sink rate on an actual aircraft career. So, there is going to be some extra "thump" on actual aircraft career.

Plus we do not know whether the AC was pushed full throttle on touch down on SBTF. It is not mandatory, since there is a long enough runway to normally stop the aircraft or gain speed to fly way. But on an actual aircraft career it is must for the extremely short deck. That full throttle adds extra stress on the airframe at capture.

IIRC, one of our mig 29k is full airframe loss already as it's spine got broken on a rough touch down. Apparently, the mig29k have been stiffened just enough to operate in a very narrow margin of safety in terms of touch down stress. Rough sea state or high cross wind or a host of conditions can push the bird easily outside that margin with catastrophic consequence. Hence they are truely being feathered. And then also the settings getting messed up at each landing.

Needless to say, none of the IAF birds need those kind of stiffening of airframe and heavy duty landing gears. These mods, along with additional equipment for naval operations (arresting hook and control mechanism, additional avionics etc), also increase their empty weight considerably reducing their weapon and fuel carrying capacity. Nor are the IAF Birds so constrained on take off or landing distance.

These design constraints made the naval birds less performing compared to their IAF counterparts invariably and those compromises definitely won't be acceptable by IAF.
Last edited by Picklu on 26 Oct 2019 00:29, edited 1 time in total.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby chetak » 26 Oct 2019 00:26

Picklu wrote:IIRC, the current sink rate on SBTF is around 75% of sink rate on an actual aircraft career. So, there is going to be some extra "thump" on actual aircraft career.

Plus we do not know whether the AC was pushed full throttle. It is not mandatory for SBTF (since there is a long enough runway to normally stop the aircraft or gain speed to fly way) while a must on an actual aircraft career for the extremely short deck.


sirji,

good points.

notwithstanding what happens on the SBTF, the proof of the pudding is always in the eating.

The only acceptable result for any customer is the actual tests on board the carrier and the successful completion of those tests.

The naval bird makes the approach for the deck with the nose cocked up, IIRC, it maybe 17 degrees, give or take.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby nachiket » 26 Oct 2019 01:03

Let us keep in mind that the IN is currently operating 45 aircraft which would have failed all these rigorous tests we are talking about. But the Russians didn't care. We have found a way to work around those shortcomings for a foreign jet while nitpicking about our own, which is already more ruggedized than the Mig-29K.

If the Russians had shown the dilligence our guys are doing, it would have taken them a lot longer to fully navalize the Mig-29K, and the aircraft would have been heavier and may or may not have met the payload and performance parameters that they can advertise now.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Indranil » 26 Oct 2019 01:24

It is quite the opposite.

At tests, they go further than the limits experienced in operational flights. At the static tests, they went to a 7.1 mtr/sec. By, the way sink rate is only one aspect of the energy. What is statically tested is a 1.5 times the limit expected in operational flights.
Now coming to ship versus STBF. A ship is sailing 20 knots into the wind. This is not a joke. 20-30 knots of headwind when you are flying at 130 knots is a BIG change. At STBF it is actually sidewinds during this time of the year. Check the wind sock in the video and you will see it for yourself. So actually, the stress of landing is higher at STBF. 

And what do you mean by flying slower than normal?!!! At 130 knots, and the AoA permitted for over the nose vision, it is at the limit of the envelop of the plane to stay airborne. 

I have a humble request. If you don't know something, please don't post. t is better to say nothing than to demean somebody's hard work. You don't know what this team is going through. Hard work while fighting with people with deep pockets. They are helpless without funding. As of today, NLCA Mk2  project stands cancelled. Ironically, it was one day before the first trap. I ask you guys, what was the day of the week when the first trap happened. Yes, it was a weekend, just before the dusshera. The team came back to Bangalore for a short break before heading back again.  And I know that some of the team did not even take that break. They went to Hindon to support LCA for IAF day. There was some problem with the smoke generator. The maintenance of that part had not been passed on to the IAF. The problem was fixed, and you all saw a wonderful show with the smoke generator. The maintenance ToT for the IAF was also completed. So please keep your opinions to yourself. These men are working.

Or else, let me take a stand. I am going to show your depth about knowledge of the program when you say something stupid or misinformed or malicious. This is not directed at anybody specific, but in general. I  don't want to do it, but there is no choice. Because this men are not allowed to stand for themselves and their work. Let me do it. If there are consequences, I will face it.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby chetak » 26 Oct 2019 02:06

nachiket wrote:Let us keep in mind that the IN is currently operating 45 aircraft which would have failed all these rigorous tests we are talking about. But the Russians didn't care. We have found a way to work around those shortcomings for a foreign jet while nitpicking about our own, which is already more ruggedized than the Mig-29K.

If the Russians had shown the dilligence our guys are doing, it would have taken them a lot longer to fully navalize the Mig-29K, and the aircraft would have been heavier and may or may not have met the payload and performance parameters that they can advertise now.


It's precisely because of the MiG 29K that the customer has wised up and he now has a much clearer idea of what he needs as opposed to what a designer/manufacturer maybe plugging by declaring that this is what you will get.

Any weapon system procured today has to be able to meet the demands dictated by the evolving threat perception and we live in a pretty wild neighborhood.

we need a flexible carrier borne platform that is versatile and can perform diverse roles within the constraints of the finances available.

So the concerned designers and the manufacturers have to be able to deliver effective platforms within fairly tight time frames or step aside to enable the induction of essentially needed equipment, albeit in some limited numbers

the russkie carrier + MiG-29K deal was piggybacked with many other projects and so we did not have a big enough stick to get our way with the bullying russkies.

Also, the geopolitical situation at that time was very different from what it is today and we did not have the options (or even the looming threats) then as the options/threats that we have now.

The customer's horrizons have been much broadened because they now frequently operate and interact with multiple navies all using high tech to maximise the bang for the buck that they have paid.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Kartik » 26 Oct 2019 03:12

Picklu wrote:IIRC, the current sink rate on SBTF is around 75% of sink rate on an actual aircraft career. So, there is going to be some extra "thump" on actual aircraft career.


Surely you have a source for this. I don't recall reading or hearing this anywhere.

Plus we do not know whether the AC was pushed full throttle on touch down on SBTF. It is not mandatory, since there is a long enough runway to normally stop the aircraft or gain speed to fly way. But on an actual aircraft career it is must for the extremely short deck. That full throttle adds extra stress on the airframe at capture.


That is part of the testing for an arrested landing as it is a Standard Operating Procedure to do so on each arrested landing on an aircraft carrier. And they were simulating just that- landing on an aircraft carrier and checking whether the airframe/arresting hook/landing gear/avionics, etc. can withstand the stresses. Why would they not try to replicate all the same control inputs that a pilot would need to put in when doing it on an aircraft carrier in a real test?

You are speculating that they probably DIDN'T do it when there is nothing to support that speculation. Remember, they were building up to actual carrier landings, so why wouldn't they make sure that the "bolter" scenario is catered for with the pilot throttling the jet to full dry power?

IIRC, one of our mig 29k is full airframe loss already as it's spine got broken on a rough touch down. Apparently, the mig29k have been stiffened just enough to operate in a very narrow margin of safety in terms of touch down stress. Rough sea state or high cross wind or a host of conditions can push the bird easily outside that margin with catastrophic consequence. Hence they are truely being feathered. And then also the settings getting messed up at each landing.


Again, not true.


PLEASE don't post this kind of "spine got broken on rough touch down" type stuff without doing some fact checking, because people pick up such unfounded rumours that are 100% wrong and it then gets regurgitated by other posters or IDRW type rags. This news could have been easily checked. The pilot lost control after aborting the take-off on the ground and veered off the runway while trying to stop the jet.

The trainer variant of the MiG-29K fighter aircraft aborted takeoff during a routine training sortie and crashed at the end of the runway.

"During deceleration, the aircraft veered off the end of runway and caught fire. The pilot jettisoned the canopy and egressed the aircraft safely," a defence spokesperson said in an official statement. The aircraft costing approximately Rs 400 crore is a complete write off, sources said.


link

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Prasad » 26 Oct 2019 06:29

Well we'll see the proof and the bloody pudding soon when the nlca gets to the carrier won't we.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby John » 26 Oct 2019 06:37

Not sure what point the posters are trying to make spewing lot of nonsense I get we want to NLCA to be inducted or Rafael whatever your agenda is but at least let’s stick to the facts. The navy chief has iterated they are happy with Mig-29k and serviceability has improved much ( go back and read up on how much trouble france had getting Rafael flying from CDG).

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby chola » 26 Oct 2019 06:55

John wrote:Not sure what point the posters are trying to make spewing lot of nonsense I get we want to NLCA to be inducted or Rafael whatever your agenda is but at least let’s stick to the facts. The navy chief has iterated they are happy with Mig-29k and serviceability has improved much ( go back and read up on how much trouble france had getting Rafael flying from CDG).


If they were happy with the 29K the Navy would have never put out the RFI for 57 new carriers. They would have just ordered more MiGs.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby John » 26 Oct 2019 08:21

^ That is like saying if AF is buying Rafale they must be unhappy with flankers it is trying to prove your point by jumping to judgement without any factual evidence. We know MiG-29k is part of this navy RFI and Russians have a tendency to jack up the price when they think they have cornered us and we have no other option. With the threat of a RFI navy could get a better deal for Mig-29ks (For example the threat of navy purchasing 2nd hand SHAR is what lead Russians to reduce the price on Gorshkov + MiG-29k).

Also I support moving away from Mig-29k if carrier with catapults is the next move, I fear mig just cannot stack up to F-18E or Rafale operating from a Catobar.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby chetak » 26 Oct 2019 10:39

John wrote:^ That is like saying if AF is buying Rafale they must be unhappy with flankers it is trying to prove your point by jumping to judgement without any factual evidence. We know MiG-29k is part of this navy RFI and Russians have a tendency to jack up the price when they think they have cornered us and we have no other option. With the threat of a RFI navy could get a better deal for Mig-29ks (For example the threat of navy purchasing 2nd hand SHAR is what lead Russians to reduce the price on Gorshkov + MiG-29k).

Also I support moving away from Mig-29k if carrier with catapults is the next move, I fear mig just cannot stack up to F-18E or Rafale operating from a Catobar.


the naval rafale has been on the IN's wishlist since even before the MiG-29K came in.

the ruskis very adamantly headed it off and went to the extent of refusing to modify the lifts. In fact, they so specifically tailored the lifts that all aircraft other than the MiG became impossible to fit in.

In hind sight, the navalised sukhoi variant, the Su-33, may have been a better fit but the russkis made us pay through the nose so that they were assured the funding for their MiG-29K project.

and, in the end, they delivered a dhobhi's pride and joy: na ghar ka, na ghat ka. :mrgreen:





per wiki

Design

Angled rear view of fighter aircraft, with the engines showing prominently. Above the engines are the two uncanted vertical stabilizers; the wings and horizontal stabilizers are folded


Image

Rear/starboard view of Su-33 with its arrestor hook visible under the shortened tail "stinger"

To adapt the original Su-27 for naval operations, Sukhoi first incorporated a reinforced structure and undercarriage to withstand the great stress experienced upon landing, particularly quick descents and non-flare landings (landings where the aircraft does not 'float' and slow its descent rate just prior to touchdown).[22]

The leading edge slats, flaperons and other control surfaces are enlarged to provide increased lift and manoeuvrability at low speeds, although the wingspan remains unchanged.[23] The wings feature double-slotted flaps and outboard drooping ailerons; in total, the refinements enlarge the wing area by 10–12%.[22] The wings and stabilators are modified for folding to maximise the number of aircraft the carrier can accommodate and to allow ease of movement on deck.[22]

The aircraft is outfitted with more powerful turbofan engines to increase thrust-to-weight ratio, as well as an in-flight refuelling probe.[22] The Su-33 sports canards that shorten the take-off distance and improve manoeuvrability, but have required reshaping of the leading edge root extensions (LERX).[23] The rear radome is shortened and reshaped to prevent its striking the deck during high-Alpha (angle of attack) landings.[24]

Compared with the rival MiG-29K, the Su-33's maximum takeoff weight (MTOW) is 50% higher; fuel capacity is more than double, allowing it to fly 80% further at altitude (or 33% at sea level). The MiG-29K can spend as much time as the Su-33 on station by using external fuel tanks, but this limits its ordnance capacity.[25] The Su-33 can fly at speeds as low as 240 km/h (150 mph), in comparison the MiG-29K needs to maintain a minimum of 250 km/h (160 mph) for effective control.[22]

However, the MiG-29K carries more air-to-ground munitions than the Su-33.[22] The Su-33 is more expensive and physically larger than the MiG-29K, limiting the numbers able to be deployed on an aircraft carrier.[4][N 2]

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby abhik » 26 Oct 2019 19:42

Did not see this posted yet: Naval LCA prepares for its Final Showdown


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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby John » 26 Oct 2019 20:08


In hind sight, the navalised sukhoi variant, the Su-33, may have been a better fit but the russkis made us pay through the nose so that they were assured the funding for their MiG-29K project.



Based on what I pieced together Su-33 can barely carry any payload taking of from a Skijump and suffers from numerous issues including poor serviceability (both China and Russia have experienced that). Once of the reasons Russia moved to Mig-29k. It was our navy that turned down Su-33 it was not Russia forcing us to take Mig-29k.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby chetak » 26 Oct 2019 20:20

John wrote:

In hind sight, the navalised sukhoi variant, the Su-33, may have been a better fit but the russkis made us pay through the nose so that they were assured the funding for their MiG-29K project.



Based on what I pieced together Su-33 can barely carry any payload taking of from a Skijump and suffers from numerous issues including poor serviceability (both China and Russia have experienced that). Once of the reasons Russia moved to Mig-29k. It was our navy that turned down Su-33 it was not Russia forcing us to take Mig-29k.


OK.

whatever you say. :)

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby John » 27 Oct 2019 03:55

Just look at all issues plaguing J-15 “flying coffin” it has one of highest crash rates and lowest serviceability of any 4th gen AC ever built. I remember 5 years ago people in BR were clamoring for why we Should have gone for Su-33 or naval Su-30mki and I kept saying wait this is not going to end well for China and even I didn’t expect to turn out this bad.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby JayS » 13 Nov 2019 08:58

NLCA demonstrated night arrested recovery. A video in this tweet.

https://twitter.com/SandeepUnnithan/sta ... 05632?s=19

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Cybaru » 13 Nov 2019 13:08

I don’t think it makes sense to make twin engine version of LCA for the small number required. Just add more raffies and call it a day and focus on amca and namca.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby sankum » 13 Nov 2019 13:36

Twin engine version of naval lca is a specific requirement of IN for INS Vikramaditya and INS Vikrant as well as IAC 2 .Even with 57 nos requirement it will be superior in peformance to naval Rafale as powerred with 20 T thrust the TEDBF will carry more load from 125 m and 140m shorter runway from Stobar carriers and meet the less than 10m width requirement.

Admiral Lamba first stated in last year navy day interview and Sjha has confirmed. Its a good development.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby ArjunPandit » 13 Nov 2019 20:18

JayS wrote:NLCA demonstrated night arrested recovery. A video in this tweet.

https://twitter.com/SandeepUnnithan/sta ... 05632?s=19

a great day...i see things moving at a faster pace as compared to past...the question remains is what role will NLCA see for IN besides a TD for future platforms...i for one would like to see one sqdn of NCLA operationg out of VikA to gain end to end operational experience...would cost a bomb..but i think it would be worth it ...

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Picklu » 13 Nov 2019 21:27

Kartik wrote:
Picklu wrote:IIRC, the current sink rate on SBTF is around 75% of sink rate on an actual aircraft career. So, there is going to be some extra "thump" on actual aircraft career.


Surely you have a source for this. I don't recall reading or hearing this anywhere.


Max sink rate 7.5 m/s whereas in SBTF they will try 5.6 m/s for carrier trial certification and currently at 5.1 m/s

Admittedly the max rate is wrong (7.5 vs 7.1 m/s) so the other's also might be a bit off but don't think total bogus.

Kartik wrote:
Picklu wrote:Plus we do not know whether the AC was pushed full throttle on touch down on SBTF. It is not mandatory, since there is a long enough runway to normally stop the aircraft or gain speed to fly way. But on an actual aircraft career it is must for the extremely short deck. That full throttle adds extra stress on the airframe at capture.


That is part of the testing for an arrested landing as it is a Standard Operating Procedure to do so on each arrested landing on an aircraft carrier. And they were simulating just that- landing on an aircraft carrier and checking whether the air-frame/arresting hook/landing gear/avionics, etc. can withstand the stresses. Why would they not try to replicate all the same control inputs that a pilot would need to put in when doing it on an aircraft carrier in a real test?

You are speculating that they probably DIDN'T do it when there is nothing to support that speculation. Remember, they were building up to actual carrier landings, so why wouldn't they make sure that the "bolter" scenario is catered for with the pilot throttling the jet to full dry power?


No disagreement on speculation. Just like they are not pushing the airframe to the max sink rate for testing in SBTF, it makes sense not to push the throttle full in the SBTF, at least in the initial series of testing. And have mentioned the same that WE DO NOT KNOW.

Finally, just for the sake of information current hook load is 37 ton whereas the actual hook load to test for will be 45 ton

Won't comment any further on the 29k spine issue. Suffice to say that NLCA designers have their work cutout for them.

And there is no disrespect to the design/engineering team. What they have done/are doing should be part of the folklore just like what GTRE achieved within it's operational constraint.

The only crux of the matter is the access to cheap capital and high end manpower. Unlike US & France (old money, global talent), Russia (Oil and Gas, soviet blue print on science and technology development) and China (all the savings of the country plus enormous trade surplus, huge allocation on education, spying plus local research), India does not have the same level playing field and must optimize allocation for the maximum bang for the buck. As Russia and China has shown, naval air power comes far down the line in priority.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Bala Vignesh » 14 Nov 2019 01:04

JayS wrote:NLCA demonstrated night arrested recovery. A video in this tweet.

https://twitter.com/SandeepUnnithan/sta ... 05632?s=19

Waah!! 2019 is proving to be a watershed year for Indian aerospace R&D.. More steam to the team!!
Lungis fully deployed!!

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Indranil » 14 Nov 2019 01:37

Picklu ji,

NLCA cannot be doing 7.1 m sink rate on shore because the SBTF is not steaming at full speed into the wind. Also the NLCA would never be doing a 7.1 m/sec unless the aircraft hits a air bubble just before landing and the ship is heaving and pitching at the same time.

NLCA traps are at full throttle. If you understand the aerodynamics of the aircraft at landing, you would know there is no other way. JayS and I wrote an article about it, if you are interested to know why.

But if you don't believe us look at video. You can't see the throttle response but you can see the movement of the flaperons by the FCS just as the aircraft touches down. It is immediately deflected up completely. That would pitch the nose up for take off if the arrest failed. In fact, NLCA was progressively tested first with traps at higher and higher speeds up to 130 knots. Then bolter tests were performed which you can see in the video too. You can see that during the high speed traps, the flaperons don't move. The FCS was not programmed for bolting. But in the case of the bolter tests, the flaperons move in the way I explained. You can see the same movement of flaperons during the traps.

I can tell you that NLCA team is completely ready for traps on Vikramaditya now. It is a matter of logistics now.


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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby JayS » 14 Nov 2019 03:48

^ +1.

7.1m/s (or 1500 ft/min) is physically difficult or even impossible to achieve at STBF. That sink rate is designed max operational load considering extreme pitching of the deck. In normal usage, the sink rate is around 4.x m/s or 700 ft/min and there is little variation in it, if deck is assumed steady, because the glide path is a fixed trajectory wrt deck.

Testing max sink rate should not be an immediate priority nor its prerequisite for carrier-based trials.

Also, no reason to consider they did not test arrested landing with full throttle slammed at touch down. The test campaign won't be complete if they have not tested this for all critical landing points.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby nithish » 14 Nov 2019 06:06

Sources confirm that #Naval #LCA trials will be conducted on the #Vikramaditya before Dec 31 this year.
@DRDO_India @indiannavy

https://twitter.com/SandeepUnnithan/sta ... 87200?s=20

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby JayS » 14 Nov 2019 10:23

^^ This shows that the recent campeign was a grand success and ADA dont see need for any significant changes in control laws which would have needed reverification. The control laws are well sorted now. Lets end the year with a bang.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby ramana » 14 Nov 2019 10:27

Great. So how many carrier landings to qualify the plane?

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Indranil » 14 Nov 2019 20:49

Tens of landings. All the tests that they did at SBTF since the first trap will be repeated on the carrier. Same with take offs.

But the duration will be shorter as they dont have to wait for favorable wind conditions.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby ArjunPandit » 14 Nov 2019 20:55

^^will end of next year be a good time for it to be completed?

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Indranil » 14 Nov 2019 21:09

Much before that.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby ramana » 14 Nov 2019 21:39

Just for perspective 7.1m/sec is 23.25feet/sec or 1500 ft/minute.
Basically the bird is dropping faster than rock on to the deck.
Most of the shock will go into the undercarriage and fuselage.

This vertical descent rate or sink rate could be for abnormal conditions like bird is landing and carrier is pitching up..

I looked up average F-18 sink rate and its quoted as normally 700 feet/minute.
So what we have is like more than double that for Naval Tejas.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby ArjunPandit » 14 Nov 2019 21:54

ramana wrote:I looked up average F-18 sink rate and its quoted as normally 700 feet/minute.
So what we have is like more than double that for Naval Tejas.


what is your perspective on that?
IMHO, for a light fighter wont that be an overkill requiring excessive safety in the landing gear, perhaps imposing weight restrictions.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby ramana » 14 Nov 2019 22:08

The Navy wrote those requirements.
Should look at what is the max sink rate for their other jets from Sea Hawks on wards.

Asking a 2X sink rate of F-18 for a light fighter would make the structure so heavy one needs to wonder why it was written at all.

Later don't blame ADA if Navy find its not agile.

Do some math.
Weight of Naval Tejas = W
Vertical descent/sink rate = 7.1m/sec
Momentum to be absorbed = (w/g)*(7.1)
All this goes into the plane landing gear and structure.
The Horizontal component will be absorbed by the cable system.
We already know the measured tension in the cable was 37 tonnes


If this high sink rate is reduced some person will claim project fail.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby JayS » 14 Nov 2019 22:11

F/A 18 is also designed for the same req as NLCA. Typical sink rate is 4.x m/s or 700ft/min and max designed is 7.1m/s or 1500ft/min. The glide path would set the usual sink rate and max pitch rate added to it would give 7.1m/s. We are following Mil Standard so we are no more conservative in design requirement than the Americans are.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby disha » 14 Nov 2019 22:21

Indranil wrote:Tens of landings. All the tests that they did at SBTF since the first trap will be repeated on the carrier. Same with take offs.

But the duration will be shorter as they dont have to wait for favorable wind conditions.


I seriously am thinking that IN and MoD must order a squadron (16 + 2) of NLCA. This will give them many birds to work with, can be used for training the Navy pilots and can even be used for missions that can take advantage of whatever capacity is provided by the NLCA.

Putting it in real situation will give it more wealth of data than any simulation.

This experience can go into NAMCA or NLCA Mk2 - whichever is the next generation of Navy LCA.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Indranil » 14 Nov 2019 23:02

ADA is pitching NLCA as a LIFT for carrier landings, in line with what the USN does with Goshawks. NLCA is certainly much more capable than a Goshawk. NAvy has not evinced any interest as of yet.

NLCA Mk2 is being completely redesigned. It won't be Naval AMCA, but a twin engined NLCA Mk2. Frankly, I am confused and so is everybody I have talked to. Navy is firmly behind a twin engine bird designed by ADA called the TEDBF. There will be some reorganization in lieu of Mk1 nearing completion, onset of MWF production and testing, onset of final design phase of AMCA, Ghatak and now TEDBF. THings will get more concrete after the reorganization.

To me the shortest path to TEDBF is through Naval AMCA. But I understand NAvy's predicament. For an AMCA sized bird, they would like the 110kN engines from day 1. With the 98 kN engines, they want something smaller and lighter.

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Kakarat » 14 Nov 2019 23:42

What is the expected MTOW?
So what will power the TEDBF? Two F404 or F414?

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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Postby Indranil » 14 Nov 2019 23:47

Not decided yet.


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