LCA News and Discussions

Arya Sumantra · Post by **Arya Sumantra** » 18 Feb 2011 13:15

Naval twin seater Tejas images
Broadsword brings you...the Tejas naval twin-seater!

suryag · Post by **suryag** » 18 Feb 2011 13:54

LSP-7's state over there shows it is not going anywhere until May atleast. After lsp3 flew what made PS promise that lsp7/8 would be ready by october ?

merlin · Post by **merlin** » 18 Feb 2011 14:06

suryag wrote:LSP-7's state over there shows it is not going anywhere until May atleast. After lsp3 flew what made PS promise that lsp7/8 would be ready by october ?

Gup is that it will take a year and a half to fly (same for LSP-8). Take it FWIW as not all people working on the Tejas know all the timelines.

Rahul M · Post by **Rahul M** » 18 Feb 2011 14:17

Sancho wrote:
Rahul M wrote:sancho, frankly you are reading too much into a picture and ending up over-analysing from what is insufficient information. FYI, there's also a pic of a 'heavier' loaded LCA going around with a PGM or tank (I forget which) on the centreline. that means nothing.

secondly, did you even look at the link I gave you ? surely, a bit of serious range analysis by an expert has more weight than what you and I 'think' ?
Don't know, I just think there must be a reason why they test exactly these configs, that's all.
I did read it, but it's comparing strike loads and ranges with Mig 21s. LCA offers the same LGB strike capability like M2Ks, or Jags don't you think?

as I said, they are not just testing exactly these configs only, these were the only ones we got to see, that's all. kakarat's post shows quite another config.

as for that link, ignore the mig-21's for the moment, digest the LCA numbers (for the 2XPGM profile f.e) first, it's very mirage-2000-ish ! get hold of m2k figures and compare if you don;t believe me.

srai wrote: Combat Air Support (CAS)

* 2 x CCM (231lb x 2)
* 2 x 1,000lb bomb (LGB/PGM/Dumb) (1,000lb x 2)
* 2 x 1,200L external fuel tank (317gallon x 8.35lb x 2)
* 1 x Liten Pod (440lb x 1)

Total Weight (external): 3,717.6 kgs

that would leave one pylon empty. also I would think they would go for 2X800 ltr tanks which they can burn off and drop during ingress. 2X1200 ltr tanks are more for ferry flights IMO.

Combat Air Patrol (CAP)

* 2 x CCM (231lb x 2)
* 2 x BVR (Derby/Astra/R-77) (441lb x 2)
* 2 x 1,200L external fuel tank (317gallon x 8.35lb x 2)

Total Weight (external): 3,010.9 kgs

again, IMO just one 1200 or 800 L tank is likely, it would fly like a truck otherwise and the asymmetric load after spending one tank would restrict maneuverability.
also doesn't use all 7 pylons.

SaiK · Post by **SaiK** » 18 Feb 2011 17:11

Those landing gears look way too solid! awesome photos and the quality of NLCA is ++.

Q: What would be the % of composite now?

aliasgar · Post by **aliasgar** » 18 Feb 2011 18:25

The amount of cabling used in the fighter is just mind blowing. Looking at the finished product, one tends to forget the number of individual components that go towards making it.
Keep it up!

Rahul M · Post by **Rahul M** » 18 Feb 2011 19:38

ali, they had this in mind and they re-designed the LRU's during the LSP run bringing down the number of LRU by a large margin, easing maintenance needs on the LCA when it enters service.

SaiK · Post by **SaiK** » 18 Feb 2011 21:02

The distributed computing based LRUs for AMCA might reduce the number of wires, and further standardize on a common bus architecture. Now going fly by light, will further reduce the number of wires except those of the power supply lines.

ramana · Post by **ramana** » 18 Feb 2011 21:07

Any ideas of how many hrs of maintenence per hour of flight and how much time to get it readied for a re-sortie? How many ground crew per aircraft?

R Charan · Post by **R Charan** » 18 Feb 2011 23:14

Israel's Derby missile is the weapon of choice for India's LCA fighter jet. A contract will be signed by March with Rafael Advanced Defence Systems Ltd to supply the air-to-air missile system to be fitted on some 200 LCA jets.

http://www.defencenews.in/defence-news- ... new&id=350

username changed to R Charan.
so far ALL your posts have been adverts of your website.
I'm allowing you for the moment on the assumption that that's not all you'll
do on BR. please keep in mind that we have zero tolerance for link spamming,
Rahul.

SaiK · Post by **SaiK** » 18 Feb 2011 23:20

ramana, I thought those metrics can be obtained only after it gets operational [post FoC].

suryag · Post by **suryag** » 18 Feb 2011 23:30

merlin wrote:
suryag wrote:LSP-7's state over there shows it is not going anywhere until May atleast. After lsp3 flew what made PS promise that lsp7/8 would be ready by october ?
Gup is that it will take a year and a half to fly (same for LSP-8). Take it FWIW as not all people working on the Tejas know all the timelines.

Hope that is 100% false or you got this info in 2009

I am not aware of wiring in aviation systems, but cant a pseudo pcb based wiring on a big scale be implemented. For example in in the underside of the skin you have traces drawn, if some signal needs to be sent from the cockpit to the rudder a wire doesnt need to run that long the cockpit will connect to this signal trace(which is a metal strip embedded in the skin during the making of the metal skin) and on the other end the rudder would connect to the other end. If we go this way the number of wires needed would be far lesser than what it is currently, it will also aid in faster manufacturing of aircraft as the integration time is cut manifold

R Charan · Post by **R Charan** » 18 Feb 2011 23:46

Israel's Derby missile is the weapon of choice for India's LCA fighter jet. A contract will be signed by March with Rafael Advanced Defence Systems Ltd to supply the air-to-air missile system to be fitted on some 200 LCA jets.

http://www.defencenews.in/defence-news- ... new&id=350

The Indian Air Force (IAF) has ordered 40 Tejas planes. The aircraft recently obtained restricted initial operational clearance, with a full clearance targeted for December 2012. While the IAF has expressed an interest for 100 of the Mk-II version of the fighter, the navy is looking for 60 of the naval versions.

Please click on the link above to read more ...

Gaur · Post by **Gaur** » 18 Feb 2011 23:47

ramana wrote:Any ideas of how many hrs of maintenence per hour of flight and how much time to get it readied for a re-sortie? How many ground crew per aircraft?

Saik's comment makes sense here. In one of Anantha Krishnan's excellent interviews, NFTC Chief had said something along the lines that a prototype needs generally needs to fly 8 sorties per month but an inducted fighter may have to carry out 8 sorties per day.

Rahul M · Post by **Rahul M** » 18 Feb 2011 23:49

R Charan wrote:........

username changed to R Charan.
so far ALL your posts have been adverts of your website.
I'm allowing you for the moment on the assumption that that's not all you'll
do on BR. please keep in mind that we have zero tolerance for link spamming,
Rahul.

srai · Post by **srai** » 19 Feb 2011 02:09

Rahul M wrote:...
srai wrote: Combat Air Support (CAS)

* 2 x CCM (231lb x 2)
* 2 x 1,000lb bomb (LGB/PGM/Dumb) (1,000lb x 2)
* 2 x 1,200L external fuel tank (317gallon x 8.35lb x 2)
* 1 x Liten Pod (440lb x 1)

Total Weight (external): 3,717.6 kgs

that would leave one pylon empty. also I would think they would go for 2X800 ltr tanks which they can burn off and drop during ingress. 2X1200 ltr tanks are more for ferry flights IMO.
Combat Air Patrol (CAP)

* 2 x CCM (231lb x 2)
* 2 x BVR (Derby/Astra/R-77) (441lb x 2)
* 2 x 1,200L external fuel tank (317gallon x 8.35lb x 2)

Total Weight (external): 3,010.9 kgs
again, IMO just one 1200 or 800 L tank is likely, it would fly like a truck otherwise and the asymmetric load after spending one tank would restrict maneuverability.
also doesn't use all 7 pylons.

You are right. The profiles I showed were for max range external load out configuration.

Here're more external load out variations:

CAS (w/ two 800L tanks)

2 x CCM (231lb x 2)
2 x 1,000lb bomb (LGB/PGM/Dumb) (1,000lb x 2)
2 x 800L external fuel tank (211gallon x 8.35lb x 2)
1 x Liten Pod (440lb x 1)

Total Payload Weight (external): 2,914.7 kgs

CAS (w/ one 800L centerline)

2 x CCM (231lb x 2)
4 x 1,000lb bomb (Dumb) (1,000lb x 4)
1 x 800L external fuel tank (211gallon x 8.35lb x 1)

Total Payload Weight (external): 2,823.1 kgs

CAS (w/ one 1,200L centerline)

2 x CCM (231lb x 2)
4 x 1,000lb bomb (Dumb) (1,000lb x 4)
1 x 1,200L external fuel tank (317gallon x 8.35lb x 1)

Total Payload Weight (external): 3,224.6 kgs

----------------------------------------------------------------------------

CAP (w/ two 800L tanks)

2 x CCM (231lb x 2)
2 x BVR (Derby/Astra/R-77) (441lb x 2)
2 x 800L external fuel tank (211gallon x 8.35lb x 2)

Total Payload Weight (external): 2,208 kgs

CAP (w/800L centerline)

2 x CCM (231lb x 2)
4 x BVR (Derby/Astra/R-77) (441lb x 4)
1 x 800L external fuel tank (211gallon x 8.35lb x 1)

Total Payload Weight (external): 1,808.9 kgs

CAP (w/1,200L centerline)

2 x CCM (231lb x 2)
4 x BVR (Derby/Astra/R-77) (441lb x 4)
1 x 1,200L external fuel tank (317gallon x 8.35lb x 1)

Total Payload Weight (external): 2,210.3 kgs

srai · Post by **srai** » 19 Feb 2011 02:38

Cybaru wrote:
Baldev wrote:standoff weapons still needs to be integrated on LCA and derby falls short of requirement.

Derby is an excellent starting point.... It will all happen in due course..

Python 5 and Derby share a lot of components with the same diameter body but slightly increased length in Derby. Both missiles have excellent close combat maneuverability. This is similar to the MBDA's MICA IR/RF design philosophy where one type of missile with interchangeable seeker can be used for both CCM and BVR. Due to its need to be used for close combat, there is restrictions in its size/weight and increased maneuverability at high-offborsight. This is partly why it suffers in the BVR range as when compared to purely BVR missiles. However, these dual use missiles weight quite less (30 to 200 kgs less) than pure BVR missiles. The other thing to point out is that in aerial combat history, BVR engagements have taken place mostly in the 30 kms or less range.

Kartik · Post by **Kartik** » 19 Feb 2011 02:56

Marten wrote:The images are of NP1. The Col. waited this while for posting the pics?

i think that the NP1 twin seater was not yet complete (from the innards) when it was rolled out earlier. Same thing was true of the 787 too when it was rolled out. They're completing all the necessary wiring and equipment fitting now and that’s why you see it as a seemingly in-build aircraft. Clearly, the structure itself is complete except for LEVCONs addition.

Dileep · Post by **Dileep** » 19 Feb 2011 06:05

suryag wrote: I am not aware of wiring in aviation systems, but cant a pseudo pcb based wiring on a big scale be implemented. For example in in the underside of the skin you have traces drawn, if some signal needs to be sent from the cockpit to the rudder a wire doesnt need to run that long the cockpit will connect to this signal trace(which is a metal strip embedded in the skin during the making of the metal skin) and on the other end the rudder would connect to the other end. If we go this way the number of wires needed would be far lesser than what it is currently, it will also aid in faster manufacturing of aircraft as the integration time is cut manifold

What will happen when a bullet pierces the skin and cuts the trace?

suryag · Post by **suryag** » 19 Feb 2011 06:16

Dileep sir if bullet could pass through skin it would most likely cut the cable too wont it ?

Prasad · Post by **Prasad** » 19 Feb 2011 06:22

Replacement cost of wire < Replacement cost of panel?

shiv · Post by **shiv** » 19 Feb 2011 06:26

I think the comment about lots of wiring is being confused by various issues including some mention of LRUs. LRUs are "Line Replaceable Units". As far as my knowledge goes the more the LRUs the better. LRUs are the aircraft equivalent of USB devices on computers.

Those of you who are closer to your birth date than your death date may not know that in the old days - every time some peripheral like a printer or even a video grabber unit had to be attached to a computer, the machine had to be switched off, the the unit connected - sometimes by opening up the box. The coming of USB created PnP "Plug and Play"

I think SDRE Indians fell in love with LRUs with the coming of the Mirage 2000. With LRUs you have modular units that sometimes can be "hot swapped" - i.e remove a malfunctioning box and replace with a spare rather than opening the hood and working with your head inside right upto musharraf. However the internal cabling is still needed and cannot be replaced. Internal cabling must be convenient and safe from both battle damage and wear and tear. There is at east one story of a civilian jet that went down because a short circuit in the cabling set a fuel line ablaze.

As regards using the skin for wiring a la PCB - what would static build up an lighting strikes do. Planes fly in hostile environments.

Baldev · Post by **Baldev** » 19 Feb 2011 06:28

srai wrote:Python 5 and Derby share a lot of components with the same diameter body but slightly increased length in Derby. Both missiles have excellent close combat maneuverability. This is similar to the MBDA's MICA IR/RF design philosophy where one type of missile with interchangeable seeker can be used for both CCM and BVR. Due to its need to be used for close combat, there is restrictions in its size/weight and increased maneuverability at high-offborsight. This is partly why it suffers in the BVR range as when compared to purely BVR missiles. However, these dual use missiles weight quite less (30 to 200 kgs less) than pure BVR missiles. The other thing to point out is that in aerial combat history, BVR engagements have taken place mostly in the 30 kms or less range.

there was report about that hal/ada has received unspecified number of 2032 radars for lca.so they had already set their mind to use derby.

Rahul M · Post by **Rahul M** » 19 Feb 2011 06:35

Baldev wrote:there was report about that hal/ada has received unspecified number of 2032 radars for lca.so they had already set their mind to use derby.

LCA doesn't use the 2032 radar in the first place. please stop this nonsense.
do read up.

shiv ji, I didn't confuse b/w amount of wiring and LRU but I took the chance to highlight an aspect of the project that doesn't get any attention.

suryag · Post by **suryag** » 19 Feb 2011 07:00

Modifying the concept of panel wiring a little further, instead of putting it on the innards of a panel, it can be done using a thinner veneer that sits between the skin and the skeleton. Static build up wouldnt be a problem but parasitic capacitance could be but given the data rate will be very small. Motivation behind this is to reduce human error while connecting and decrease in the mass and increase in the ease of production. All of this could be total nonsense too but thought would sound it off

rgsrini · Post by **rgsrini** » 19 Feb 2011 08:04

Gurus might have already seen this. But I thought I will post this for folks who are stunned just like me at the amount of wire in LCA. I was thinking (uninformedly) to myself that there may be quite a bit of weight reduction opportunity here and I was asking uncle google for more details.

Here is one site I found that has a lot of details on this. I am just beginning to read this...

http://www.vision.net.au/~apaterson/avi ... ft_design.
ASPECTS OF AIRCRAFT DESIGN THAT ENHANCE SAFETY

Mostly related to passenger aircraft. But has a lot of information about electrical wire types and the electrical fire risk associated with improper selection of wires.

Hope it helps.

karan_mc · Post by **karan_mc** » 19 Feb 2011 08:22

In aero India some one did tell me that few MMR were actually made in Israel ,and even tested on their test bed before it was shipped to India to be mated with Indian backhand radar components ,i am not sure how true it is

Cain Marko · Post by **Cain Marko** » 19 Feb 2011 08:35

All this newj coming aut of SDRE airshow but golly, no LCA cockpit pic wonlee.

Where is my fix?
CM

Rahul M · Post by **Rahul M** » 19 Feb 2011 08:36

karan_mc wrote:In aero India some one did tell me that few MMR were actually made in Israel ,and even tested on their test bed before it was shipped to India to be mated with Indian backhand radar components ,i am not sure how true it is

it's the other way around.

ramana · Post by **ramana** » 19 Feb 2011 09:07

Srai, So does LCA do toss bombing?

svinayak · Post by **svinayak** » 19 Feb 2011 09:12

srai wrote:
CAS (w/ one 1,200L centerline)

2 x CCM (231lb x 2)

4 x 1,000lb bomb (Dumb) (1,000lb x 4)

1 x 1,200L external fuel tank (317gallon x 8.35lb x 1)
Total Payload Weight (external): 3,224.6 kgs

Can this configuration be used for Nuke bomb delivery.
It looks like it can do the 300Kg to 500Kg weapon for ground toss.

shiv · Post by **shiv** » 19 Feb 2011 14:04

I had a very interesting conversation today with a VIP whom you will all know - my little birdie. I actually called him to pick his brain and ask him about average airspeeds flown by fighters at airshows. I mentioned the LCA and remarked that the show I had seen from the golf course (where I sometimes bump into him) was more exciting than the on at Aero India. His reply was fascinating. The LCA shows at Aero India were software restricted to 6 G. The software will not allow the pilot to pull more than 6 G. They wanted to ready the software to allow up to 7 G before Aero India but that was not possible. So its the fault of all you ITivity guys:

I then asked about opening up the envelope and high AoA tests and about the anti-spin parachute. I specifically wanted to know whether that parachute would be on wing pylons or what. There is a software angle to that as well. The software currently will not allow the LCA to exceed a specified AoA. That restriction will be removed before the high AoA tests so that the pilot is actually able to pitch the nose up in an unlimited fashion and not be restricted by software. The anti spin parachute will be in the tail and is a much longer one than the brake parachute.

The real issue is that an "irrecoverable spin" is flat one in which the plane has its musharraf down, its nose up and is floating down spinning flat with air flowing the wrong way. The only way to recover from this is to deploy an anti-spin parachute that will lift the musharraf up, get the nose down and get the plane's airflow in the right direction. Of course the designers have some idea of how the LCA will behave from vertical wind tunnel tests and there is no reason to think that it will misbehave and go into a flat spin after a stall from High AoA. But real world tests are essential - the Gripen has apparently had 250 spin trials.

suryag · Post by **suryag** » 19 Feb 2011 14:23

you will all know

Hakim ji the anti-spin parachute is only a precautionary measure when testing for spin or will it be a permanent fixture(may be not). Also in FBW based systems does the computer know it has entered a spin and bring the pilot out of it even without his intervention ? Chachaji says it depends on how FBW is architected. And the thing that Shooklaw ji said that the intakes are not well designed for 28deg AoA and will stall is that true?

shiv · Post by **shiv** » 19 Feb 2011 15:10

suryag wrote:
you will all know
Hakim ji the anti-spin parachute is only a precautionary measure when testing for spin or will it be a permanent fixture(may be not). Also in FBW based systems does the computer know it has entered a spin and bring the pilot out of it even without his intervention ? Chachaji says it depends on how FBW is architected. And the thing that Shooklaw ji said that the intakes are not well designed for 28deg AoA and will stall is that true?

Two things:

1) There is no intention to make the LCA go into a spin. The idea is to increase the angle of attack gradually. The anti spin parachute is IF the aircraft stalls and IF it happens to go into an unrecoverable spin. Two ifs. The aircraft may not stall and even if it does it may not go into an "unrecoverable" spin. it may go into a recoverable spin.

2) The FBW system can do nothing in an unrecoverable spin where the plane has found itself a stable way of spinning down to earth with musharraf down and airflow in the wrong direction. In other types of spin I guess the FBW software to be set to take the corrective action like neutralizing control surfaces.

Shukla is talking stuff that nobody knows anything much about, He can't know either. The IAF has not asked for 28 degrees as far as I know. but even if it has, it has to be tested and certified and if the airflow is wrong the AoA will have to be restricted to 27 degrees until design changes are made. These are well known stepping stones in the development of any aircraft. Tests on models have not shown that the LCA is likely to misbehave but it is 2011 and not 1911, and this is India, not China. We must not send combat pilots up before testing and certifying. that's what tests pilots are there for.

Viv S · Post by **Viv S** » 19 Feb 2011 16:51

I'm having trouble wrapping my head around the idea that the Tejas (or any modern fighter aircraft for that matter) can enter an unrecoverable spin without any flaws in its FCS. How??

As long as he has control over the elevons and engine, he will be able to eventually 'right' the aircraft. Would be dicey at a low altitude but fairly safe over say... 20,000ft.

shiv · Post by **shiv** » 19 Feb 2011 18:40

Viv S wrote:I'm having trouble wrapping my head around the idea that the Tejas (or any modern fighter aircraft for that matter) can enter an unrecoverable spin without any flaws in its FCS. How??

No. The FCS will have to be overridden, or a catastrophic failure has to occur such as an engine shut down during a steep climb at low speed such as occurs shortly after takeoff. The idea is that eventually combat pilots will get an aircraft that they can freely throw about, but right now, in the testing phase, nobody knows exactly how it will behave at high AoA above the current tested setting when "freely thrown about". That will be done in a controlled manner, gradually "releasing" the FCS to allow the aircraft to do more and more "daring things" - like flying slower and slower at a higher and higher angle of attack and in a simultaneous turn or bank - presumably with enough and more altitude to spare and each time the stall or near stall will be done under different conditions. I am guessing that if it does stall and go into a spin - it may well be a spin that it can recover from. Among all the scenarios in which it might spin, there could possibly be one attitude + control surface setting + speed + environmental condition in which an unrecoverable spin can occur. Apparently some aircraft just don't spin. They are just freaky and will be no good for training pilots in spin recovery. That will not be even discovered until tests are done thoroughly. This appears to be standard run of the mill stuff - albeit tricky and extremely important in all aircraft testing. And unless tested the FCS cannot be written to prevent or forestall the particular situation.

The IJT of course will be actually allowed to spin. The spin characteristics and recovery are important in pilot training. There was a great article about this in Vayu by Air Mshl Rajkumar who tested both the Hawk and Alpha Jet.

vina · Post by **vina** » 19 Feb 2011 19:58

Shivji, ..long long long ago, there was an article published about the spin testing the LCA and the recovery parachute and everything.

The point is an artificially stabilized aircraft like the LCA will not be allowed to spin in the first place. It is an out of control condition for the FCS and the "eject eject" warnings will immediately start screaming and the pilot punches out! The spin modes of such an aircraft tend to be violent, highly non linear , oscillatory in most cases and probably not recoverable by the plane's own control surfaces (which are totally Paki at this point) and needs an external force (aka recovery parachute). No heroic fighting the controls to recover the aircraft from a spin by the Pilot Herrow like in the movies !

I think what they will do is to check the RESISTANCE to spins by opening the envelope and pushing the plane to it's absolute limits . And if it does spin, the spin recovery parachute will be deployed to recover and once the recover happens, plane is nose down and Musharraf up, the parachute will be cut and the plane "flies down the hill" like normal and is recovered. The max limits to which the plane is tested will be the ultimate "carefree" limits that the IT/Vity boys will set on the software so that the operational pilots can throw about with abandon on a daily basis.

vina · Post by **vina** » 19 Feb 2011 20:20

suryag wrote:And the thing that Shooklaw ji said that the intakes are not well designed for 28deg AoA and will stall is that true?

Sorry. That was him Harrumphing as he is sometimes given to from the "nuggets" given by his Chaiwallahs.

X deg AoA will certainly NOT be an IAF ASR! AoA is just a means to an end and not an end in itself . It is not a d*ck measuring contest like Bandar does A, mine will be B , and Ding Dong J-XX will be C !

If suppose the plane need to be stable and controlled at very low speeds then the design will call for some X AoA and if it needs to pull the designed 9gs /10gs/11gs/whatever gs, that will require some Y AoA and therefore the plane need to be proven at the max X or Y AoA that the flight envelope demands and the FCS will limit the AoA to the proven flight tested value in the squadron service versions.

The good Colonel's oh, the F-18 can do 58deg AoA, while the Tejas will drop out of the sky at 28deg (which I doubt is anywhere close to the truth) or the F-16 has a max AoA of only some 30 deg or so is only a d*ck measuring contest and has absolutely no relevance.

Bharadwaj · Post by **Bharadwaj** » 19 Feb 2011 21:01

Something sounding like a Tejas just flew past Whitefield .... Pretty late for a test flight...

merlin · Post by **merlin** » 19 Feb 2011 21:03

Gaur wrote:
ramana wrote:Any ideas of how many hrs of maintenence per hour of flight and how much time to get it readied for a re-sortie? How many ground crew per aircraft?
Saik's comment makes sense here. In one of Anantha Krishnan's excellent interviews, NFTC Chief had said something along the lines that a prototype needs generally needs to fly 8 sorties per month but an inducted fighter may have to carry out 8 sorties per day.

<Nitpick>The LCA prototypes fly about 8 times a month, whereas an inducted fighter may have to carry out 3-4 sorties per day, not 8</Nitpick>