LCA News and Discussions, 22-Oct-2013

brar_w · Post by **brar_w** » 31 Dec 2014 20:40

@ Victor, Shalav is saying precisely that. FBW allows you to open up designs that you could not fly without it. As Ben Rich put it a few years before his death, the SR71 had stealth features, but the inherent challenge was to get it to fly at mach 3.2, yet still fly slow enough so that it could refuel from a tanker. RCS reductions therefore could only be incorporated as long as they did not interfere in the flight qualities and the design enabling the qualities demanded. As he put it Once I had the flight control system, I could make anything fly. Fly‐by‐wire was the secret to stealth. it freed up configuration

fanne · Post by **fanne** » 31 Dec 2014 20:47

Victor Sahib,
Again, I do not know if you are trying to rewrite the whole vocabulary of aeronautics, but F117 is an unstable aircraft (as in CG is behind neutral point). Stable aircrafts (where CG is in front of neutral point) can be easily flown by humans and do not need FBW. But many do have FBW to make it easy to fly (computer does most flying). Good examples are all Airbus and now Boeing transport planes.
All unstable planes however would need FBW, at least at high speed. It would be humanly impossible for human to fly it (though wright brother plane was unstable). At low speed, it is doable perhaps.
Now conventional plane, that I do not know, what is that? one owned by Air India?

Victor · Post by **Victor** » 31 Dec 2014 20:52

Brar ji by "conventional" I meant wings, fuselage, tail in back. What was left unsaid is that unconventional aircraft (like the F117) can be unstable in ALL ASPECTS not just wing loading, essentially a flying brick, while a "regular" (perhaps that's the word I should have used?) aircraft can have instability designed in by reducing the wing area (increasing the load it carries). I think we are talking past each other and I fully agree with your post.

putnanja · Post by **putnanja** » 31 Dec 2014 21:02

Victor wrote:
Shalav wrote:
They can't be both conventional and unstable! Conventional aircraft (ie non-fbw) by definition are stable.
They can. I meant an aircraft like F-117 which shouldn't be able to fly but does due to FBW.

Victor wrote:Brar ji by "conventional" I meant wings, fuselage, tail in back. What was left unsaid is that unconventional aircraft (like the F117) can be unstable in ALL ASPECTS not just wing loading, essentially a flying brick, while a "regular" (perhaps that's the word I should have used?) aircraft can have instability designed in by reducing the wing area (increasing the load it carries). I think we are talking past each other and I fully agree with your post.

Didn't you just contradict yourself? In response to Shalav, you said F-117 can be both conventional and unstable, while saying F-117 is unconventional in your next post?

I think you just need to stick to stable and unstable designs. And highly wing-loaded aircraft can be stable too.

fanne · Post by **fanne** » 31 Dec 2014 21:14

Victor Sahib,
Take a break. Wing loading has nothing to do with stability. An unstable plane can have high or low wing loading (compared to what?), so can a stable aircraft.

unconventional aircraft (like the F117) can be unstable in ALL ASPECTS not just wing loading - Makes no sense. It like saying mango tastes sweet because plank constant cannot be more than energy in quarks (whatever that means)!!

while a "regular" (perhaps that's the word I should have used?) aircraft can have instability designed in by reducing the wing area (increasing the load it carries). - This is plainly wrong.

Shalav · Post by **Shalav** » 31 Dec 2014 21:34

Victor wrote:
Shalav wrote:
They can't be both conventional and unstable! Conventional aircraft (ie non-fbw) by definition are stable.
They can. I meant an aircraft like F-117 which shouldn't be able to fly but does due to FBW.

The F117 is an unconventional aircraft. Perhaps you mean the layout, with wings in front and stabiliser at the back? May I suggest you use the term "conventional layout" !

BTW wings in front with stabiliser at the back is the unconventional layout. The first aircraft flown by the Wright brothers had a front stabiliser, with wings aft of it. So if we keep this as a reference layout, all aircraft with stabilisers at the back are unconventional layouts! But that's just being pedantic.

FBW is used to control unstabilised aircraft, which can be due to moving CG or CL either aft or forward from its natural position. High wing loading has nothing to do with FBW. The F104 with its very high wing loading flew quite well with hydraulic controls. It was a stable aircraft.

Jagan · Post by **Jagan** » 31 Dec 2014 22:19

Newly released HD video of the Ski Jump test - with more camera views and footage - Courtesy of the LCA Tejas Team

http://www.youtube.com/watch?v=dB73FdERNBA

Karan M · Post by **Karan M** » 31 Dec 2014 22:26

Thakur_B wrote:Alright. IAF has been very very tightlipped about the ODL and it's status otherwise.

Question: Do navy harriers use Link-2 to communicate like other navy assets?
Also, how many fighters would be able to share data in a group using ODL ?

Havent seen it mentioned for the Harrier. Could be it datalinks via its Israeli datalink to the carrier directly or to the Ka-31 which then uses Link-2 to talk to the carrier.

About ODL - need to check. But these specs match what I remember and IAI is the primary partner.
http://www.iai.co.il/Sip_Storage//FILES/9/39429.pdf

Victor · Post by **Victor** » 31 Dec 2014 22:30

The eggspurts on this thread (who are aeronautical engineers) have declared that I am spreading "bullcrap" and thus it must be so. No reasoned response, no rebuttal, just abuse. It's below me to stoop to their level but let me say that I fully believe that it is they who know little themselves (about aeronautics) and base their views on book knowledge alone without a clue (or "feeling" if you will

) about real flight with the single focus on "proving" that the LCA is an acceptable frontline aircraft. In my case, at least I've designed and flown airplanes, even if they were models, besides having flown a real single engine Cessna and can claim to actually understand that layman info and know relatively well what works. I've never maintained that I am an "expert" because if I were, I'm sorry to say the chances of me having time to post on forums would be extremely limited if not forbidden. I do however actually know and have worked with such experts (not from HAL/ADA unfortunately) and at every professional interaction with them, my knowledge of aerodynamics, such as it is, gained from models has proven very sound and been acknowledged as such by these real experts. Not always but a lot of the time. That doesn't mean what I write is gospel, far from it. What it does mean is there's a good chance that most of the time, I'm not writing bullcrap even if I don't throw out a torrent of tech-sounding alphabet soup but rely instead on layman lingo for the benefit of all.

About the gent who declared that he has put me on his ignore list--should I be afraid? Disappointed? Or care? Are you relevant to me? Anyway, thanks for removing yourself from my field of perception. I can do with less distraction. Same for anyone else who has the inclination. I just request that you not become paki about it.

Having said that, I reiterate that what I wrote is correct to the best of my understanding. If you care to rebutt then please do so with due respect to all. Or feel free to walk on by. I think a lot of the heat on this thread has to do with proving one side or the other of the LCA argument. In support of the "LCA is good" argument, what is being bandied around as "maneuverability" uses sustained turn rate as a cornerstone measure when it is not so relevant today, having been replaced by the ability to change direction of high speed flight quickly to attempt escape from oncoming missiles. There was a chart a few pages ago that showed that clearly. In today's world of missiles that can turn around 180 and shoot the guy behind you (off-boresight for the alphabet soup challenged) merely by turning your head (HMD), sustained turning is clownish. What is the point of the LCA turning tightly in circles by itself if it has already been left far behind by all its faster opponents?

For the whizzards who keep quoting "LCA is order of magnitudes better than Mig21", pray explain why IAF ordered (with reluctance) only 40 LCA but retains hundreds of ancient Migs instead? Fact is, of course LCA is a "better" aircraft because it uses a new generation of technology, like aforesaid volvo vs jonga. But is it a better fighter aerodynamically in spite of this new tech? The IAF says NO. Period.

Again, the alphabet soup wallas keep saying I'm running down the "Indian LCA" for "obvious reasons". Why be shy to point it out--what reasons? Can you support that view? May I turn that suspicion around 180 degrees? Who exactly benefits from forcing the IAF to accept an inadequate fighter for frontline service? Hmmmm.....

fanne wrote:your statement regarding higher wing loading meaning more maneuverable is plain wrong.

I assume the statement in question is: "..higher wing loading is the biggest determinant of an "unstable" conventional aircraft which in turn is what defines maneuverability, including STR and ITR."? If so, I have already suggested that I may not have been 100% precise with my wording in implying that lower wing loading (a big, fat wing) does not help sustained turning without losing altitude (STR) when I meant to point out that STR is a part of maneuverability. From my observations on this board, I don't believe anybody here will think that, even those who are not aeronautical engineers.

Getting back to topic, I have always maintained that the LCA, being an old design, is not relevant today. The idea of a light figter is out of date and all attempts at making a pig dance won't succeed. It doesn't help to dress up this simple fact, satyameva jayate etc. I also maintain that the PSUs are messing things up due to their inadequate level of expertise and management coupled with outsize egos. All of this I'm simply repeating from the most senior IAF folks' published reports since defer to IAF views always. Not sometimes, not most of the time but always.

However, I have also said repeatedly that LCA is a must-win project for India, eventually with an Indian engine, that it is a "good" design that must be improved to become usable today and this is my only personal "feeling", also happily shared by the IAF. The discourse here should IMHO be on sharing our own ideas on how this may happen based on our several backgrounds and experience and on the abundance of available info. Bottom line is the LCA in its current form, even the FOC version, will be unacceptable to the IAF and will have to be changed. That is the whole point of LCA Mk2 and the small (under duress) order of 40. Where do we go from here?

BTW, Happy New Year to all jingos. A truly wise old coot told me that a "year" is 365 days and we shouldn't wait to start something on January 1 or end something on December 31. A new year always starts today.

fanne · Post by **fanne** » 31 Dec 2014 22:37

Pilot sahib happy new year!!!

Mihir · Post by **Mihir** » 31 Dec 2014 23:03

Respected Victor-ji who has flown a Cessna(!) first wrote:Matheswaran and Khokhar point to the problems: the LCA fares badly in turn rate, climb rate and range. The turn rate and climb penalties would give it a severe disadvantage in close combat

Respected Victor-ji who has flown a Cessna(!) then wrote:In today's world of missiles that can turn around 180 and shoot the guy behind you (off-boresight for the alphabet soup challenged) merely by turning your head (HMD), sustained turning is clownish. What is the point of the LCA turning tightly in circles by itself if it has already been left far behind by all its faster opponents?

PratikDas · Post by **PratikDas** » 31 Dec 2014 23:26

Jagan wrote:Newly released HD video of the Ski Jump test - with more camera views and footage - Courtesy of the LCA Tejas Team

http://www.youtube.com/watch?v=dB73FdERNBA

Jagan Ji, this video is a celebration and needs to be appreciated with gusto.

Happy New Year to the LCA team. We really need FOC for the IAF version ASAP.

krishnan · Post by **krishnan** » 31 Dec 2014 23:36

check the slow motion

Victor · Post by **Victor** » 01 Jan 2015 00:00

Mihir wrote:
Respected Victor-ji who has flown a Cessna(!) first wrote:Matheswaran and Khokhar point to the problems: the LCA fares badly in turn rate, climb rate and range. The turn rate and climb penalties would give it a severe disadvantage in close combat

Respected Victor-ji who has flown a Cessna(!) then wrote:In today's world of missiles that can turn around 180 and shoot the guy behind you (off-boresight for the alphabet soup challenged) merely by turning your head (HMD), sustained turning is clownish. What is the point of the LCA turning tightly in circles by itself if it has already been left far behind by all its faster opponents?

And respected Mihir ji has missed the point, as usual.

Karan M · Post by **Karan M** » 01 Jan 2015 00:01

Mihir,

What what. Recognise the genius saar. Reading those expert contributions to the LCA discussion is the equivalent of this contribution to world music.

https://www.youtube.com/watch?v=drtd-GqNXds

Karan M · Post by **Karan M** » 01 Jan 2015 00:06

PratikDas wrote:
Jagan wrote:Newly released HD video of the Ski Jump test - with more camera views and footage - Courtesy of the LCA Tejas Team

http://www.youtube.com/watch?v=dB73FdERNBA
Jagan Ji, this video is a celebration and needs to be appreciated with gusto.

Happy New Year to the LCA team. We really need FOC for the IAF version ASAP.

Beautiful. The fact it was an automated take off with the special carrier take off software is even better. A decade back we had to go abroad to even get autopilot software for our fighters. Now thanks to this program we have that and even such further specialized software.

rgsrini · Post by **rgsrini** » 01 Jan 2015 00:34

victorji wrote:Who exactly benefits from forcing the IAF to accept an inadequate fighter for frontline service?

India, Indian aeronautical capability, Indian Industries, Indian economy in the short, medium and long term
IAF's capabilities in the medium and long term.

Inadequate in some respects, yes. However, to overcome the inadequacy and improve the reliability, there is no option but to induct the aircraft in numbers. We (India and IAF) cannot afford to indefinitely wait for the "perfect" aircraft.

Indranil · Post by **Indranil** » 01 Jan 2015 01:04

Jagan wrote:Newly released HD video of the Ski Jump test - with more camera views and footage - Courtesy of the LCA Tejas Team

http://www.youtube.com/watch?v=dB73FdERNBA

Plus notice the wind sock. The winds were gusting at over 15 knots down the runway.

SaiK · Post by **SaiK** » 01 Jan 2015 02:21

does ins-hansa has arresting gear system installed or TBD?

Cybaru · Post by **Cybaru** » 01 Jan 2015 02:54

Ah that is some excellent footage! The under belly camera showing front and back and the harrier chase plane is pretty cool! Also the inside cockpit view was super nice!

vina · Post by **vina** » 01 Jan 2015 09:35

Beautiful. The fact it was an automated take off with the special carrier take off software is even better. A decade back we had to go abroad to even get autopilot software for our fighters. Now thanks to this program we have that and even such further specialized software.

No.. No. Take off is only just half of what was tested. Look at the footage carefully. To me it looks like a typical high sink rate, flareless carrier approach. The only thing missing was the tail hook snagging and arrested stop. But it does look like the stuff like modes to hold glidescope, angle of attack, auto throttle etc were tested in the flight as well.

It seemed like just a take off, go about and land. The wheels were still spinning from the take off right until landing (you can see that during landing).

ravip · Post by **ravip** » 01 Jan 2015 10:13

Everything that navy does whether it is was the first flight or this sbtf video, it is truly a Jingo's wish. So much of detail we get to see. Thanks to the team for video and wish them all the best for 2015.

chackojoseph · Post by **chackojoseph** » 01 Jan 2015 10:26

rgsrini wrote:
victorji wrote:Who exactly benefits from forcing the IAF to accept an inadequate fighter for frontline service?
India, Indian aeronautical capability, Indian Industries, Indian economy in the short, medium and long term
IAF's capabilities in the medium and long term.

Inadequate in some respects, yes. However, to overcome the inadequacy and improve the reliability, there is no option but to induct the aircraft in numbers. We (India and IAF) cannot afford to indefinitely wait for the "perfect" aircraft.

Wasn't SU-30 MKI forced on IAF?

SaiK · Post by **SaiK** » 01 Jan 2015 10:34

On 1080p it looks magnificent! so no weapons afsar/copilot here?

Yagnasri · Post by **Yagnasri** » 01 Jan 2015 10:47

Victorji, I do not think LCA is going to be a frontline AC. It will be Mango man AC for numbers and b&b AC with more than M2k capabilities in many aspects which itself is a great upgrading of the over all force capabilities than mig21 level force of the present days. With our level of tech, economic and production capabilities we can not do better for the time being. We all wish we can and have to do much much much better and our forces need F22 level capabilities yesterday. But we have to be relistick.

Sid · Post by **Sid** » 01 Jan 2015 12:22

chackojoseph wrote:
rgsrini wrote:
India, Indian aeronautical capability, Indian Industries, Indian economy in the short, medium and long term
IAF's capabilities in the medium and long term.

Inadequate in some respects, yes. However, to overcome the inadequacy and improve the reliability, there is no option but to induct the aircraft in numbers. We (India and IAF) cannot afford to indefinitely wait for the "perfect" aircraft.
Wasn't SU-30 MKI forced on IAF?

Off topic but it was procured in direct response to Chinese Su27 procurement. A reactive action, not becuase it was some Heavy combat aircraft.

This issues was well covered in a Vayu article as well, i lost that copy.

chackojoseph · Post by **chackojoseph** » 01 Jan 2015 12:27

M2K was IAF choice. MKI was forced.

Indranil · Post by **Indranil** » 01 Jan 2015 12:34

I would like to revisit the question of need to redesign the inlet of Mk2. Saurav Jha had said (quoting Dr. Tamilmani) that Mk2 inlet does not need any change. His argument was that the airflow of the 414 is almost the same as Kaveri and the flight regime is not changing, so the inlets don't need a change. I did not have much time earlier to think about it, but now that I have looked at a few things, I would like to question that.

1. With significantly different airflows (70kg/s vs 77kg/s), inlet diameter (71cm and 79 cm) and the same designed flight regime, how can the same inlet be efficient for both? So either the pressure recovery is not efficient for the 404 or the 414.
2. Will the length of the inlet remain the same? The length of the 404 and the 414 is the same, but the distance between C.G. and the nozzle most probably is going to change with the body plug. If the wing is aligned so that C.G. aligns with 33.5% of the MAC of the wing, and the distance from the lip the intake and the leading edge of the wing stays the same as Mk1, the length of the intake will also change.
3. Take -off and landing are not design points of inlets and engines. But blow-in doors don't belong to a plane desinged in 2015.

Any thoughts?

MODERATOR NOTE: Serious discussions please. If you feel something please keep it to yourself. Pure science please. Anything else, and I WILL warn you.

kmkraoind · Post by **kmkraoind** » 01 Jan 2015 13:03

Saurav Jha ‏@SJha1618 Here's an early rendering of the LCA from AW&ST sporting a cranked delta wing via Elider at SecretProjects.

deejay · Post by **deejay** » 01 Jan 2015 14:01

indranilroy wrote:I would like to revisit the question of need to redesign the inlet of Mk2. Saurav Jha had said (quoting Dr. Tamilmani) that Mk2 inlet does not need any change. His argument was that the airflow of the 414 is almost the same as Kaveri and the flight regime is not changing, so the inlets don't need a change. I did not have much time earlier to think about it, but now that I have looked at a few things, I would like to question that.

1. With significantly different airflows (70kg/s vs 77kg/s), inlet diameter (71cm and 79 cm) and the same designed flight regime, how can the same inlet be efficient for both? So either the pressure recovery is not efficient for the 404 or the 414.
2. Will the length of the inlet remain the same? The length of the 404 and the 414 is the same, but the distance between C.G. and the nozzle most probably is going to change with the body plug. If the wing is aligned so that C.G. aligns with 33.5% of the MAC of the wing, and the distance from the lip the intake and the leading edge of the wing stays the same as Mk1, the length of the intake will also change.
3. Take -off and landing are not design points of inlets and engines. But blow-in doors don't belong to a plane desinged in 2015.

Any thoughts?

MODERATOR NOTE: Serious discussions please. If you feel something please keep it to yourself. Pure science please. Anything else, and I WILL warn you.

Saar, non Techi only here

. My teachers could not get much science in me even in school

. But another noob pooch/s for the gurus:
a) With the change in engine and also thrust will the max Mach No. change?
b) Will this change in Mach no. (if any) have any impact on existing designs for things like intake, leading edge, etc

and on a diff note
c)With reduced weight, increased fuel, higher thrust, lower engine SFC, hence longer ranges and / or higher load outs how much is the Mk 2 better than Mk 1, as in does it justify a lower Mk 1 order and the bulk fleet on Mk 2?
d)alternatively, will a 100+ Mk 1 order leave much room for a large order of Mk 2 from IAF?
e)Won't Mk 2 go from Mk 2 to Mk 2 ver1.1, ver1.2 and so on or we have not thought about that yet?

Yagnasri · Post by **Yagnasri** » 01 Jan 2015 14:05

KMKRaoji, Great picture.

Aditya_V · Post by **Aditya_V** » 01 Jan 2015 14:10

PratikDas wrote:
Jagan wrote:Newly released HD video of the Ski Jump test - with more camera views and footage - Courtesy of the LCA Tejas Team

http://www.youtube.com/watch?v=dB73FdERNBA
Jagan Ji, this video is a celebration and needs to be appreciated with gusto.

Happy New Year to the LCA team. We really need FOC for the IAF version ASAP.

Beautiful. The fact it was an automated take off with the special carrier take off software is even better. A decade back we had to go abroad to even get autopilot software for our fighters. Now thanks to this program we have that and even such further specialized software.

Might be irrelevant but nice to see a Sea Harrier doing chase plane duties in this case.

maitya · Post by **maitya** » 01 Jan 2015 15:52

indranilroy wrote:I would like to revisit the question of need to redesign the inlet of Mk2. Saurav Jha had said (quoting Dr. Tamilmani) that Mk2 inlet does not need any change. His argument was that the airflow of the 414 is almost the same as Kaveri and the flight regime is not changing, so the inlets don't need a change. I did not have much time earlier to think about it, but now that I have looked at a few things, I would like to question that.

1. With significantly different airflows (70kg/s vs 77kg/s), inlet diameter (71cm and 79 cm) and the same designed flight regime, how can the same inlet be efficient for both? So either the pressure recovery is not efficient for the 404 or the 414.
2. Will the length of the inlet remain the same? The length of the 404 and the 414 is the same, but the distance between C.G. and the nozzle most probably is going to change with the body plug. If the wing is aligned so that C.G. aligns with 33.5% of the MAC of the wing, and the distance from the lip the intake and the leading edge of the wing stays the same as Mk1, the length of the intake will also change.
3. Take -off and landing are not design points of inlets and engines. But blow-in doors don't belong to a plane desinged in 2015.

Any thoughts?

MODERATOR NOTE: Serious discussions please. If you feel something please keep it to yourself. Pure science please. Anything else, and I WILL warn you.

The mass-flow for Kaveri and F414 are same ~78kg/s and though I don't know (off-hand) the inlet-diameter of Kaveri, it shouldn't be too different from that of F414 (given they both same handle mass-flow and also assuming they would allow similar engine-entry velocity of say ~0.6M).
So, IMO, the air-inflow design shouldn't require too much of a change - apart from removing/re-adjusting what ever "narrowing" etc they would have done to reduce the mass flow to ~69kg/sec for F404.

Do note the inlet diameter diff between F404 and F414 (to account for this larger massflow of approx 10kg/sec) is approx 3inches - so for a similar mass-flow-of-Kaveri similar inlet dia should have been provisioned for in the original LCA design.
However this provisioning for inlet dia etc is less impportant, from airframe structural design perspective, compared to fitting-in the max-width of the engine ... typically they are an order of magnitude more. For e.g. for both F404/F414 the max-engine width is ~890mm (compared to 910mm for Kaveri).

Similarly, length wise Kaveri (at 3490 mm) is ~40cm shorter than both F404/F412 (at 3912 mm) - but if the current TDs/PVs/LSPs/SPs are able to accomodate for these ~40cm addn length of the F404, it should be able to accomodate the F414 of the same length.
Moreover there's minimal 10Kg weight difference between Kaveri (design weight of 1100Kg) and that of F414 (F404 is lighter at 1036Kg).

So IMO, structurally fitting in F414 may not be such an issue.

However, even slight change in CG position may not be that easy to adjust (as you have point out). But we don't know enough about where is the CG of F414 (vis-a-vis that of F404) located to do that kind of analysis - however, generally speaking, the heaviest aspects of a turbofan are the Fan, followed by the LP compressor stages, so the CG should be towards the "forward portions" of them.

Pratyush · Post by **Pratyush** » 01 Jan 2015 16:15

Isn't the 414 designed to be plug in replacement for the 404?

That being the case, if the design can use the 404, should also be able to deal with the 414.

RajD · Post by **RajD** » 01 Jan 2015 18:31

Gurus, could anyone please explain why the chase plane the harrier also has its landing gear not retracted? I presume the LCA has just taken off and certainly is not on the glide path for landing.
Regards.

JohnTitor · Post by **JohnTitor** » 01 Jan 2015 19:05

Karan M wrote:
PratikDas wrote:Jagan Ji, this video is a celebration and needs to be appreciated with gusto.

Happy New Year to the LCA team. We really need FOC for the IAF version ASAP.
Beautiful. The fact it was an automated take off with the special carrier take off software is even better. A decade back we had to go abroad to even get autopilot software for our fighters. Now thanks to this program we have that and even such further specialized software.

Very nice, but why no arrested landing? If I recall, one of the issues was the weight of the landing gear - I'm assuming thats been sorted.. would have been nice to see arrested landing as well.

Congratulations to the team , never the less!

fanne · Post by **fanne** » 01 Jan 2015 19:14

I believe first they will complete all kinds of take offs, the final being full combat load at 90 meters. Then the testing for landing gear will start. Initially an empty plane with low sink rate and least velocity possible ( where the plane will not stall and if misses the hook then can still take off). Gradually that will move to real conditions.
Rgds,
Fanne

shiv · Post by **shiv** » 01 Jan 2015 21:12

"Arrested landing" is merely catching a hook on a cable. More important is the sink rate and banging the plane down on the surface at a high sink/descent rate. That can be tested without arrested landings

member_28108 · Post by **member_28108** » 01 Jan 2015 21:24

First test flights are usually without landing gears retracted. You can see the Airbus 380 first test flight - they did not retract it. Usually after some flights the landing gear retraction is tested as a special test.Another thing is the first test is usually a take off turn around and landing so no real time to retract and release the landing gear.Basically the scope and objectives are different with different tests.

JohnTitor · Post by **JohnTitor** » 01 Jan 2015 22:44

Thanks guys.

shiv ji, would you not also want to test the structural strength of the landing gear due to the stress of essentially being pulled in two directions ? I was under the impression that this was the main thing that they tested for.