LCA News and Discussions

suryag · Post by **suryag** » 30 Sep 2011 12:43

Content in www.ada.gov.in has now been updated
The AURA project has been renamed IUSAV and lots of other content updated - not sure if it is a good idea to put the names of the scientists involved

Philip · Post by **Philip** » 30 Sep 2011 12:58

As an aside,the JSF is in serious financial straits and one option being looked at is the dumping of one fo the three versions,carrier cat version or the STOVL version.Despite the ability of the STOVL version to return with her load of armament and fuel intact,a problem with carrier landing aircraft which "slam" onto the flight deck and have to often dupm payload and fuel.The USMC wants large numbers of this version as their amphibious ships of approx. 50,000t size do not have cats.They can only operate STOVL JSFs,but the Brits are in a fix as they are now going to operate only one carrier,train (humiatingly) with the French too (Napoleon must be laughing in his tomb at Les Invalides) to share operating costs.

I however have my doubts about the naval LCA's usefulness,Being a small single-engined aircraft,it will possess a restricted operating combat radius of action with a limited load of ordnance,restricted too by ski-jump take-offs. In addition,being single-engined,it is vulnerable to any engine failure where a twin-engined aircraft could shut one down and returm home.Perhaps being a small aircraft and manufactured locally (even though much of the LCA is firang) ,it will be easier to operate from our smaller medium sized carriers and gave a role more suited to fleet air defence rather than long-range strike which will be carried out by the MIG-29Ks.

Indranil · Post by **Indranil** » 30 Sep 2011 13:14

Shubham,

It is very nice to see your interest and obviously you are not a complete newbie ... however you are just confusing with too many things.

I am little busy till this Sunday so I will write up a short reply ... may be other gurus can pitch in the meanwhile.

For any plane, as you increase the AoA,

1. the drag increases and the thrust decreases ... the point where these two curves meet is the maximum AoA that you can sustain ... if you increase the AoA beyond this point, you would obviously be slowing down and would finally reach your stalling speed for that AoA.

2. second part of handling high AoA is obviously where the wing stalls.

The smaller of these two angles is the AoA that you can sustain for a given plane. Generally for modern fighter aircrafts the limiting AoA is the AoA derived from point 1. This is because of the usage of numerous kids of vortex generators used on the wing to delay edge separation. On the other hand the engine is tucked behind a long air intake.

This is exactly what you see is happening with the LCA.

Using the recovery chute is a contingency measure ... with LSP 6, they would relax the computer to let LCA pitch up more and more till either the engine can't generate enough thrust to overcome the drag and the plane quickly decelerates towards the stall speed at that AoA. The pilot would obviously see the oncoming stall and try to recover the plane by decreasing the AoA, to increase the thrust and lower the drag and avert the oncoming stall. This point will be the max AoA that LCA can handle. If it is found to be low, they would have to work to make it higher.

However if he loses authority of the plane, he would use the chute to put his nose down to get better airflow (as you identified).

All this is if his engine doesn't stall and he has enough altitude to try relighting it ... beyond a certain threshold, if he can't relight, he would eject.

shiv · Post by **shiv** » 30 Sep 2011 14:05

Aditya_V wrote:
Shiv but would not ferry ranges with drop tanks and flying at fuel efficient speed differ widely with Combat radius where maximum dry thrust, use of after burners plus sometimes lo-lo profile will be used. Even the F-15C has a ferry range of 4500KM but its combat range would be nearly half that.

The Tejas' ferry range is quoted as Jamnagar-Banaglore = 1800 km

My guesstimate of its radius of action is 600 to 700 km. Approximately 1/3rd of ferry range. That still covers Pakistan and most of Tibet without AAR.

shiv · Post by **shiv** » 30 Sep 2011 14:13

Shubham wrote:
2. Because of the risk of stalling and spinning
will a simple practice stall of a delta wing ac cause it to enter spin regimes ??
From the video of Vijeta posted in another thread, I deduced that entry into practice spin is similar to that of practice stall, just that there at 105 kts the controls are mishandled(whereas the stalling speed is ~98 kts in dirty).

Of course I am assuming that currently the pilots are not able to reach desired alpha in LCA even in level flight(due to above two reasons).

I am no expert. But the whole idea is NOT to get into an unpredicted uncontrollable situation. This can happen. Air Marshal Rajkumar told me that the Gripen went through more than 1000 high AoA tests many of which went on after it entered service.

I am guessing that even with LCA in most cases nothing much will happen but the data generated will be recorded for feeding to flight control laws. But the stall/spin chute is an insurance against losing the aircraft in case it gets into some unexpected unrecoverable spin.

vina · Post by **vina** » 30 Sep 2011 14:43

The Tejas' ferry range is quoted as Jamnagar-Banaglore = 1800 km

The config you quoted is not the "ferry config" , which will be all wet points loaded to the gills with fuel, no war load.

From what you described, it seems like it was carrying weapons (I would guess 2 A2G munition and the dummy R73s) and from the pics I have seen of Tejas, 2 drop tanks.

So ferry range would be lot more than this, if the centerline tank was loaded and the bombs not carried and that could be of the order of 3300 Kms give +- 200Km or so.

chackojoseph · Post by **chackojoseph** » 30 Sep 2011 15:06

shiv wrote:
Aditya_V wrote:
Shiv but would not ferry ranges with drop tanks and flying at fuel efficient speed differ widely with Combat radius where maximum dry thrust, use of after burners plus sometimes lo-lo profile will be used. Even the F-15C has a ferry range of 4500KM but its combat range would be nearly half that.
The Tejas' ferry range is quoted as Jamnagar-Banaglore = 1800 km

My guesstimate of its radius of action is 600 to 700 km. Approximately 1/3rd of ferry range. That still covers Pakistan and most of Tibet without AAR.

Effective air combat range 150 - 200 kms. Includes low flying, dog fight etc.

=============================

Added later. With refueling, the bird will be a pain in the yellow Ar$e over uttar Arunanchal Pradesh. With or without refueling Tejas + Rafale/Typhoon will bad combination for the other side. All hail to Delta gods.

shiv · Post by **shiv** » 30 Sep 2011 16:19

chackojoseph wrote:
Effective air combat range 150 - 200 kms. Includes low flying, dog fight etc.

That is as bad if not worse than MiG 21 unless I am mistaking the meaning of the words "air combat range"

Austin · Post by **Austin** » 30 Sep 2011 16:22

Remember a Janes specs on LCA which quotes the combat radius as 200-250 km what ever that means.

Aditya_V · Post by **Aditya_V** » 30 Sep 2011 16:38

shiv wrote:
chackojoseph wrote:
Effective air combat range 150 - 200 kms. Includes low flying, dog fight etc.
That is as bad if not worse than MiG 21 unless I am mistaking the meaning of the words "air combat range"

Yes no way it is that bad, the Tejas range should be what Shiv states.

AdityaEngineer · Post by **AdityaEngineer** » 30 Sep 2011 17:01

@shubham The formula is not wrong surely because you can find it in the very popular RK BANSAL FLUID MECHANICS.@other members Tell me what could be the measures required to improve AoA (refinement in CFD Simulation model).But if this is the thing they are going to do then why?Because modern CFD Simulators are designed in such a way that practical conditions can be feed into them.Also as far as body design is concerned why does DRDO keep mum everytime when IAF says that intake design is not right ?

Lalmohan · Post by **Lalmohan** » 30 Sep 2011 18:05

highly cambered (curved) aerofoils have higher aoa's - but come at the penalty of high drag and generally low speed
a slightly cambered aerofoil which can be altered using slats and flaps with the boundary layer reattached with slots and vortex generators allows thin cambered aircraft like fighters to fly at higher aoa
and then you need thrust (as has been pointed out) to overcome drag
have lots of thrust, you can slam the aircraft at higher than normal aoa - even backwards if you so wish

now the question is, why do you want/need high aoa?

mostly its required for landing and also for turning rapidly (though other complex mechanics plays a part too)
the real question is what is the right level of compromise in aoa vs speed vs thrust vs weight?

neerajb · Post by **neerajb** » 30 Sep 2011 19:20

Correct me if I am wrong, My understanding says ferry range means one way max range with possible max load of fuel and the flight profile optimised for max range. Whereas combat range or combat radius is the max distance an aircraft can go and then come back with useful warload including combat maneuvering etc. So theoritically combat radius cannot exceed 50% of ferry range.

Cheers....

Shubham · Post by **Shubham** » 30 Sep 2011 19:24

@AdityaEngineer
ok, i will rephrase it as, your formula is incomplete as well as valid only for small values of alpha.
Coeff of Lift = 2 pie sin(alpha), could be valid for a specially designed aerofoil at small values of alpha, anything you change on or external to the aerofoil will change coeff of lift which is not reflected in the formula.

Things that can be changed on the aerofoil - camber, aspect ratio, sweep, vortex generator, boundary layer fences, LE/TE flaps, slats, slots, smoothness of the surface, spoilers, area of the wing(shape and size), winglets, strakes, boundary layer control(blowing or sucking

of energized airflow) ...

Things that can be changed externally - Reynold's number(this itself will include most of the atmospheric variables), ...

Since there are so many factors which affect Coeff of Lift and thus lift, they should find a place in the formula for it to be correct and complete.

Kanson · Post by **Kanson** » 30 Sep 2011 19:50

Ferry range can be definitive with or without external tanks. Combat range is highly subjective. Usually mentioned for a typical profile for a particular role, ex. Jaguar. If the plane is multirole, there could be various ranges for various roles and profiles.

Cain Marko · Post by **Cain Marko** » 30 Sep 2011 20:37

My guess is this:

Range - place A to B with full internal fuel = 1800-2000km, closer to the 2000km mark perhaps. That is excellent - equal or better than M2k, and close to F-16 (2000km). Combat radius with about 6 AAMs is assumed to be about 50% of range, my guess is about 900km.

Combat radius with heavy stores + EFTs ~ 200km. Nothing to be ashamed of, IIRC, the solah or 18 (despite their large size) manage around 3-400km.

200 nm (370 km) + 2 hr 10 min patrol
w/ 2 AIM-7 + 2 AIM-9 + 1,040 US gal external tanks

Fas.org for the F-16.

No worries, this is excellent for a bird that small. All depends on what Chacko means by "effective air combat range"

CM

chackojoseph · Post by **chackojoseph** » 30 Sep 2011 20:42

shiv wrote:
chackojoseph wrote:
Effective air combat range 150 - 200 kms. Includes low flying, dog fight etc.
That is as bad if not worse than MiG 21 unless I am mistaking the meaning of the words "air combat range"

IMO, MK II (extrapolating with the MK I figures you gave) with GE 414 and a heavier payload will put pressure on the fuel gauges. I don't yet see it venturing more than 200 kms for a bait and kill typically characterized by low flights, rapid climb up and sustained dog fight and landing back in the nearest base. The Janes 200 -250 KMs I recon is fag end of the ops.

In mud mover mode, she can do max - 500 kms radius.

I see this truly 4.5 gen replacement for Mig-21.

Willing to see a debate on this.

===
Added later. I am not doing a pure math here. I am estimating for what she will be cleared for.

SaiK · Post by **SaiK** » 30 Sep 2011 20:43

wouldn't combat time and capabilities are right measure than range in dog fights?

range is more for point to point bombing raids, interception and precision delivery missions, is my thought.

for dog fights it is all about how much time you have, and what all you can do to kill and return.

e.g: I can be within 50km range, and still finish off 10 J20s, and return back after a successful mission.

But, dunno about range and combat for missions like say you have to fly for 500kms, and then do your dogfights, and return back. This is where, mid-air refuelers comes in to extend mission time.

chackojoseph · Post by **chackojoseph** » 30 Sep 2011 21:03

You are right. Ferry range means nothing. We are not transporting cattle.

I am willing to be corrected.

In a pure low flying bait role or escort role, I see it guzzling fuel. 200 kms.

In a mid - low risk right altitude escort/ dog fight mission, it can stretch up to 250 kms.

In a pure delivery role, low flight, climb up, release and high speed dash back, it will be 500 kms.

IMO, IAF or any other force will not allow it to be stretched into fag end of the calculations.

SaiK, there will be a lot of loitering for a contact and kill. it will be safe to keep the birds in an envelope for safety measures.

krishnan · Post by **krishnan** » 30 Sep 2011 21:23

Various websites put the "Combat Radius" between 1100 to 1400 km

Austin · Post by **Austin** » 30 Sep 2011 21:32

krishnan wrote:Various websites put the "Combat Radius" between 1100 to 1400 km

They would be right if that includes couple of external fuel tanks and certain light payloads .

I think there are factors like pure radius it can fly with certain payloads and tanks or it can fly within certain radius with say 30 - 35 minute of on station time.

If memory serves me right didnt a certain tejas test pilot say that though she is small but her endurance almost matches that of M2K.

Singha · Post by **Singha** » 30 Sep 2011 21:42

I see its air patrol mission being 2 wing tanks, 4 big aams (derby / astra1) and 2 small aams. jmho dog fighting will generally not be part of routine because people will try to go for bvr shots and avoid the unpredictable risks of going in close into guns type engagements .... except when hunting strike a/c making for targets wherein the attack has to be pressed home even if missiles miss either to sink them or force them to dump payload and turn away.

but a lot of fuel does get burned in the phase where a fighter has to rush to a suitable position either from its CAP location or its airbase to effect a intercept. this is where the big internal fuel tanks of F-15C / Su30 types permit them to 'reach out' long and fast.

SaiK · Post by **SaiK** » 30 Sep 2011 22:02

chackojoseph wrote: SaiK, there will be a lot of loitering for a contact and kill. it will be safe to keep the birds in an envelope for safety measures.

that means you are ignoring situational awareness systems - missions without external air support is impossible for IAF. threats are increasing by the days and years we take decisions to get pakfs, amcas and the upgrades. not dhoti shivering, but dhoti pressing that we are at least aware about the capabilities. It only improves our security and feeds as inputs for future plans and upgrades.

sivab · Post by **sivab** » 30 Sep 2011 22:22

deleted

nachiket · Post by **nachiket** » 01 Oct 2011 01:36

Singha wrote:I see its air patrol mission being 2 wing tanks, 4 big aams (derby / astra1) and 2 small aams.

That is too much. That would require 8 hardpoints, 1 more than what the LCA has, or multiple payload racks. My guess would be either 1 centerline EFT + 4 Derby/Astra + 2 R-73 OR 2 wing mounted EFTs + 2 Derby/Astra + 2 R-73.

SaiK · Post by **SaiK** » 01 Oct 2011 02:25

Is the centerline designed for eft payload? or is it the adjacent one? But, the racks option would increase the number of astras then, 2 per pylon would be nice.

Cybaru · Post by **Cybaru** » 01 Oct 2011 02:26

I would think that the profile would be more like 2 short and 2 long range AA missiles and a 2 hour CAP time at high altitude. It may even carry a center line fuel tank.You are going to be at high altitude for your cap. You are not going to be turning and burning at low level until engagement. So for most AA CAP's you will get a 2+ hour sortie out of it. If they can get CFT's at some point that would be great another 1200 gallons of fuel and another 20-30 minutes of loiter time.

It is also quite easy to get 3-4 hour cap time from these puppies as Midas mamma is around.. Get to sector, sucker up and loiter around for 2-3 hours in your sector.

For mud moving role, I would think you would litening pod/shiva pod on center line. two fuel tanks in internal wet point and 3 250kg lgb kits on the middle hard point. I think it will always have CAP provided by AWACS/SU types when it is on a mud moving mission. Again most of these guys are going to be in a large package type flotilla (8-10 mixed aicraft types) backed by Awacs. package will have AA/SEAD/DEAD/Mud-movers etc. All of them will get refelled before entering enemy airspace just to be safe. (So something like two SU's/Migs providing Air to Air cover, Rafale/mirage carrying sead/dead package to shut down any Ground to air batteries that may open up around intended target area and 6-10 JAGS/LCA each carrying 1500-2000 Kgs of A2G payload. All under awacs cover.

I think we think of each item separately too much. If this puppy can deliver 1500 kgs on target, that is quite a bit of damage. 5-10 of these in a package would mean a good 7500-15000kg payload delivered on target. That is quite a lot.

Ravi Karumanchiri · Post by **Ravi Karumanchiri** » 01 Oct 2011 03:00

I hope this doesn't veer the thread OT, but it's relevant to the current discussion....

It seems to me that the IGMDP focus on building very fast cruise missiles (Brahmos and Shaurya), with very sophisticated terminal targetting (reportedly capable of distinguishing among a cluster of buildings), would seem to indicate a strike plan wherein the DEAD role would be at least partially addressed with missiles, likely before an IAF scramble.

It makes perfect sense to me; to take out air defenses and enemy runways, prior to Indian aircraft appearing on enemy radars. By then, it'll be like "What enemy radars?"

Such a strike plan would presumably also entail refuellers penetrating (sanitized) enemy airspace, to refuel Indian aircraft after they have dropped their heavier ordinance, with subsequent CAPS being flown without bombs or EFTs tucked under wings, just AAMs. This would be the ideal use for the small, light, single-engine LCAs, IMHO.

Does this make sense, or is it way wrong?
Please advise. Thanks, RK

Cosmo_R · Post by **Cosmo_R** » 01 Oct 2011 04:36

@Ravi Karumanchiri ^^^. Check what Shiv said about the need to constantly re-bomb runways. DEAD perhaps but runways?

IMHO, if at all possible, you'd do standoff glide bombs from 40K feet perhaps from within Indian airspace.

The old swoop in and drop a few bombs is WWII

Singha · Post by **Singha** » 01 Oct 2011 07:08

its time to explore a dual rack pylon system for astra1 atleast. if you look at F-15E the main pylons have side pylons sticking out at 90' to hang more missiles from.
the rafale ofcourse has the famous triple rack for AASM and the tornado has a similar one for Brimstone.

so the 2 x side pylons could mount the R73, while the main pylons carry the 4 X derby/astra, permitting a clean centerline (or jamming pod) and 2 x wing fuel tanks.

in strike role the side pylons could carry 2 x R73 for self-defence and the rest devoted to bombs and fuel tanks.

chackojoseph · Post by **chackojoseph** » 01 Oct 2011 07:48

SaiK wrote:that means you are ignoring situational awareness systems - missions without external air support is impossible for IAF. threats are increasing by the days and years we take decisions to get pakfs, amcas and the upgrades. not dhoti shivering, but dhoti pressing that we are at least aware about the capabilities. It only improves our security and feeds as inputs for future plans and upgrades.

What sitrep got to do with the endurance? AWACS or no AWACS, if it needs to fly that profile that I have mentioned, that includes altitude, fuel availability, load etc. What AWACS and other controllers can do is to use the a/c within the envelope. I don't think AWACS and controllers get a/c parameters in the datalink. They will have to ask the a/c how much fuel/ armaments and flight time it has got.

IMHO.

krishnan wrote:Various websites put the "Combat Radius" between 1100 to 1400 km

With Ferry range of 1800 Kms, 1400 combat range is dubious without refueling. The most optimistic scenario will be it flies 600 kms one way, fires a BVR or drops the load and returns. However, can happen only with the countries having no air force or marginal/residual air force where there will be no chases or there is a refueler + protective air defense within the vicinity. In this case, it is a shame to send Tejas because they should be sending an a/c with higher payload + self protection load.

Cybaru · Post by **Cybaru** » 01 Oct 2011 08:02

Ravi Karumanchiri wrote:I hope this doesn't veer the thread OT, but it's relevant to the current discussion....

It seems to me that the IGMDP focus on building very fast cruise missiles (Brahmos and Shaurya), with very sophisticated terminal targetting (reportedly capable of distinguishing among a cluster of buildings), would seem to indicate a strike plan wherein the DEAD role would be at least partially addressed with missiles, likely before an IAF scramble.

Sure, some missiles will always be used before a scramble, but there will still be mobile systems that will need to be taken care of and that will need a sead unit along with your strike package to ensure success of package delivery. Assume china, you won't get all their radar systems and lots of them will need to be countered once you cross the border. Can we load all planes with required sead/aa/electronics or have one unit in the package that can cover for everyone. All units are multi-role, but they don't have to be multi-role during every delivery. If one/two rambha can be tasked with AA with awacs watching over and another pair with SEAD to suppress any mobile units on the way or around a target, then the 10 odd other planes in the package can just move mud all along without worrying.

Drishyaman · Post by **Drishyaman** » 01 Oct 2011 08:06

SaiK wrote:we should soon find a conformal LCA taking off in the future, when the uprated engine arrives.

This would be a welcome development. Extra internal fuel and internal weapons bay, somewhat like the F-15 Silent Eagle. With AESA and internal weapons bay we would be having a 4.5 Gen Tejas tending to be 5 th Gen. As, Carlos Ghosn would say “Frugal Indian Engineering”, Big Bang for the buck.

Cross- Posting

Vinito wrote:Looks like a similar effort to what the Americans are doing on the F-15 with the silent eagle upgrade

shiv · Post by **shiv** » 01 Oct 2011 08:16

chackojoseph wrote:The most optimistic scenario will be it flies 600 kms one way, fires a BVR or drops the load and returns.

Or it can go 500 km, spend 10 minutes on target and return.

SaiK · Post by **SaiK** » 01 Oct 2011 08:31

chacko, it depends how you want to use it, right?

One can build fantastic systems, say a raptor.. [heard about its problem in communication with other airborne support systems, so much for being stealth to even talking to friendly systems].

It would not just remain aware, but applied rather. I know my targets precisely where, and how it is moving and in minutes I am done with my job and back home in a few more..and have a short quickie, and then return back to next mission.

The mission planners have only intervals to send another sortie... it just happens, and the game plan is so dynamic, that based on your applied awareness, you will either win or get beaten.

But, again, I am speaking from just with coherent thoughts. Actuality could be entirely different especially with classified information.

chackojoseph · Post by **chackojoseph** » 01 Oct 2011 08:41

shiv wrote:
chackojoseph wrote:The most optimistic scenario will be it flies 600 kms one way, fires a BVR or drops the load and returns.
Or it can go 500 km, spend 10 minutes on target and return.

Yes. I have mentioned that for mud mover (see below). And it could be 500 KMS + 10 Mins as you put it for a escort role in a medium threat environment.

I have estimated the ideal flight envelops at situations we might face "mostly." There can be N number of permutations and combinations, which depends on situations. We should not be calculating by pure maths and try to estimate the "confidence" levels of the makers and fliers to exploit the maximum performance for a given situation. There might be situations where they will be going extremes due to situation, but, its not on everyday basis. If you read Jagan/Sameer and PC Lal's books, you will find the pilot recounting that "particular a/c is good for xyz altitude and capability" during extreme conditions.

chackojoseph wrote:
IMO, MK II (extrapolating with the MK I figures you gave) with GE 414 and a heavier payload will put pressure on the fuel gauges. I don't yet see it venturing more than 200 kms for a bait and kill typically characterized by low flights, rapid climb up and sustained dog fight and landing back in the nearest base. The Janes 200 -250 KMs I recon is fag end of the ops.

In mud mover mode, she can do max - 500 kms radius.

I see this truly 4.5 gen replacement for Mig-21.

Willing to see a debate on this.

===
Added later. I am not doing a pure math here. I am estimating for what she will be cleared for.

chackojoseph · Post by **chackojoseph** » 01 Oct 2011 08:48

SaiK wrote:chacko, it depends how you want to use it, right?

One can build fantastic systems, say a raptor.. [heard about its problem in communication with other airborne support systems, so much for being stealth to even talking to friendly systems].

It would not just remain aware, but applied rather. I know my targets precisely where, and how it is moving and in minutes I am done with my job and back home in a few more..and have a short quickie, and then return back to next mission.

The mission planners have only intervals to send another sortie... it just happens, and the game plan is so dynamic, that based on your applied awareness, you will either win or get beaten.

But, again, I am speaking from just with coherent thoughts. Actuality could be entirely different especially with classified information.

No matter how you want to use it, you cannot use it beyond its capabilities. It won't perform miracles. AWACS is just a ariel antenna with decision taking and cannot alter the characteristics of the aircraft. What they can do is to use the aircraft within its parameters (which essentially you are already saying) given the capablities, limitations and situational capabilities/limitations (like availability of fuel/kind of load/opponent profile/ Time on target etc). Pls read my above post, else will have to repeat the same stuff here.

SaiK · Post by **SaiK** » 01 Oct 2011 08:59

aye aye ! but also do some c2bm. please feel free not to repeat.

chackojoseph · Post by **chackojoseph** » 01 Oct 2011 09:24

What is c2bm?

Added later;

Command, Control, and Battle Management?

SaiK · Post by **SaiK** » 01 Oct 2011 09:39