LCA News and Discussions, 22-Oct-2013

[Indranil]

flight test graph, they have revamped the ada website, looks more profestional now

Also IUSAV is most probably called Ghatak now

[Indranil]

From NAL's director's report 2012-2013

Improved Air Data System (ADS) versions have been released for the LCA Air Force and Naval aircraft. Wake trials have been conducted after incorporating wake identification feature in the ADS.

Lot of more information about MAVs.

[SaiK]

Tejas operating from Leh in the winter of 2013, at an altitude of 3,524 m (11,562 ft). The temperature was often down to -15 degree Celsius at night and the day temperature rarely exceeded 0 degree Celsius. Leh has one of the highest commercial airport in the world.

from tejas.gov.in
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[Aditya_V]

Question to Gurus- where is the LCA's canon placed and has the GSH 23mm cannon ever been fired from LCA?

[krishnan]

ghatak seems to me deleterious

[Rahul M]

Question to Gurus- where is the LCA's canon placed and has the GSH 23mm cannon ever been fired from LCA?

double barrel under starboard intake.


surprisingly, I couldn't find a piece that talked about cannon firing. although articles indicate it has been done.

[srai]

Well wonder whether a second production line for Tejas in the private sector might be feasible ?

Let me ask you few questions and you should be able to figure out the answer yourself:

1. Total Quantity - how many LCAs are required by the IAF?
2. Operational Capacity - how many LCAs can the IAF operationalize (budget, manpower, other resources) in a month/year?
3. SMEs Capacity - what is the capacity of hundreds of Small Medium Enterprises (SMEs) to deliver parts and material? Can they increase capacity accordingly to accommodate second production line? If not are there other competing SMEs who can do the job?
4. Trained Manpower - other than HAL can the "private" second line get the trained manpower required? How many are there available?
5. Infrastructure costs - How much will the assembly infrastructure cost to be built? Who will foot the bill? Are there sufficient orders for investment justification?
6. LCA IOC2/FOC - when is the final production variant design ready? The assembly line can't deliver until the product is ready and is specified accurately for production.
7. Revenue/Profits - what is the break-even point (investment costs, production costs vs sales revenue)? How much is the revenue and profits? What's the revenue growth forecast?

[Aditya_V]

Thanks a lot,

Yes I would think some important things to at least A to A capable

1) Firing Derby or Any MRAAM

2) Firing Python IV or V, more R-73 firings

3) Firing Short range AAM's from inner pylons.

4) Firing cannons in A to A mode.

Given the location of the Canon, in dogfights one presumes that the LCA should have the bogie either straight ahead or below its nose, a limitation when you are trying to fire on some while turning in, but many fighters like F-4 and Mig 21FL/M have had that.

[GeorgeM]

Question to Gurus- where is the LCA's canon placed and has the GSH 23mm cannon ever been fired from LCA?

double barrel under starboard intake.


surprisingly, I couldn't find a piece that talked about cannon firing. although articles indicate it has been done.

The cannon appear quite setback towards the middle, it could mean better accuracy, since it is closer to the CG I guess.

[Yagnasri]

I think the last word on the numbers is not yet said as the cost may be a serious issue, we may end up without any Rafael. In such case more Lca mk2 may be acquired. Further China actions must have raised some serious need for numbers. So the success of mk1 will be continuing and much bigger orders for mk1 and 2 may be than the present projections. The advances in mk2 will not doubt help us with AMCA project.

In all great future and bigger role may be there for Tejas than we now think.

[Hitesh]

I was checking the Wiki page for LCA and comparing it to Gripen. Why is the combat radius so low? It says its combat radius is 300 kms whereas Gripen is 850 km radius? They have similar empty weight. However loaded weight is greater for LCA and maximum take off weight is greater for Gripen. What is loaded weight? what is the difference?

[Aditya_V]

Hitesh_> I don't think LCA combat radius has been published, and combat radius varies based on mission type. I doubt Gripen has nearly 3 times the combat radius of Tejas.

Gripen has 3008 liter tank, while Tejas has 2458Kg(don't know how many liters this translates too) but is lighter.

Wiki numbers have to be taken with a bit of salt. if you wiki you will believe Bandar can detect fighters and engage them at 150km and is soon slated to get AESA.

[Kartik]

Question to Gurus- where is the LCA's canon placed and has the GSH 23mm cannon ever been fired from LCA?

double barrel under starboard intake.


surprisingly, I couldn't find a piece that talked about cannon firing. although articles indicate it has been done.

which articles talk about the cannon being tested? AFAIK, there has been no cannon firing as yet, and that was to be done in the phase between IOC-2 and FOC.

[Kartik]

Given the location of the Canon, in dogfights one presumes that the LCA should have the bogie either straight ahead or below its nose, a limitation when you are trying to fire on some while turning in, but many fighters like F-4 and Mig 21FL/M have had that.

I don't get what you stated here..where else did you expect the cannon to be located? Below the fuselage in a fairing is standard placement for cannons, and behind the intake to avoid gun gas ingestion into the intake which may cause an engine stall.

And how does the placement affect its dogfighting capabilities?

[Aditya_V]

Karthik, as mentioned by you and in my earlier posts, yes many fighters have it this way, there over wing options like SU-30 and F-16. Just wondering whether placement of canon makes a difference in a dogfight, I am no real world fighter pilot , if there are any references where this has been discussed online, I would like to know.

cause when you are turning in to some one you probably wish you can engage targets above your nose, however, under body placement might be more useful when engaging ground targets. Thats all.

[Lalmohan]

the canon is set up to strike shells at a point x m in front of the nose of the aircraft, allowing for ballistics and aerodynamics - which makes the placement of the canon less relevant. it is however more relevant from gas ingestion perspective, etc.

in a turning fight, the pilot has to estimate where the shells will end up (usually not where his nose is pointing at that time). this is why (i think) lead computing gunsights were developed, which adjust for some of these parameters. you aim for where you think the bogey will be when the shells get there

the canon itself is not steerable (unlike in some attack helicopters)

[srin]

Seeing the pic, I have a slightly different concern - the cannon placement seems to take away one hard-point.

[SaiK]

perhaps it is the angle of the photograph



those things in front of the gun will be tucked in anyways when it fires.

[nikhil_p]

A quick question -

What happens when a round 'cooks off' in the barrel of the gun. Or there is a Jam. Wouldn't this affect the fuel / control linkages, etc which as it is close to the engine might create a potentially dangerous issue.

[Mihir]

Just wondering whether placement of canon makes a difference in a dogfight, I am no real world fighter pilot , if there are any references where this has been discussed online, I would like to know.

The gun is always angled upwards or downwards depending on the mission the is primarily designed to carry out.

http://ricks.foreignpolicy.com/posts/20 ... anes_and_s

What most non-tactical jet pilots don't know is that air-to-air and air-to-ground cannon are mounted differently. An aircraft with an air-to-mud cannon is at a gunsight depression disadvantage in a dogfight, and the opposite is true for fighter pilots who wish they were heroic attack pilots. Consider for a moment. If your primary mission is to make earthmen miserable, the axis of your cannon will be depressed from the longitudinal axis (fuselage) of your aircraft. This allows pilots to enjoy a more shallow dive and therefore leisurely opportunities to perforate the rabble and break their toys. Fighter pilots, conversely, have cannon that are biased above the longitudinal axis, because most of our enemies don't like to get shot and are pulling as many G's as they can to keep from getting their jump wings. If your gun is pointing up a few degrees, you don't have to pull your nose all the way to the bogey's jet before your glowing "death dot" is resting on the back of his helmet. This also means that F-16 and F-22 pilots have to strafe in a steeper dive and shoot quicker to keep from suffering cement poisoning.

[Aditya_V]

So underbelly cannon generally is more in Air to mud role as since it cannot be aimed higher up the longitudanal axis since the Body of the aircraft comes in between, whereas over wing cannon cannot be depressed on the longitudanal axis.

So in an underbelly canon to get thee death dot on the bogie you probably have to turn 1/2 a degree more than cannon mounted over the wing.

[SaiK]

A quick question -

What happens when a round 'cooks off' in the barrel of the gun. Or there is a Jam. Wouldn't this affect the fuel / control linkages, etc which as it is close to the engine might create a potentially dangerous issue.

MTBF check onlee.. rest is all maintenance. i don't see this as dangerous issue (btw, what is the issue you are bringing up from an assumption?) - we are already dealing with safety-critical systems here. And.. we 'd have a line waiting to hear such discussions to DDM world soon.

[Lalmohan]

IIRC mig27 canon had a slight downward angle

[Mihir]

So underbelly cannon generally is more in Air to mud role as since it cannot be aimed higher up the longitudanal axis since the Body of the aircraft comes in between, whereas over wing cannon cannot be depressed on the longitudanal axis.

It depends. For a MiG-27-esque cannon, placed well towards the rear, inclining it above the longitudinal axis would be tough. Not so for the LCA, whose cannon is just behind the intake. Remember, the rounds are expected to travel a kilometre or so; hence the offset would need to be no more than a fraction of a degree.

Lalmohan, the MiG-27's cannon was indeed inclined downwards, but not just to allow shallow dives during strafing runs. The reasons were quite different. The GSh-6-30 was an extremely powerful gun, probably the most powerful to be installed on a fighter until then. But that power came at a price; it was heavy, imposed significant impact loads on the airframe, cooling was troublesome, and vibrations were intense. The first ground testbed pretty much fell to pieces when firing commenced. During flight trials, the impact and vibrations led to avionics failures, deformation of the structure, landing gear doors falling off, and other such fun stuff.

Dealing with the recoil was the biggest problem. The gun produced a recoil of around 5000 kgf, which was more than half the dry thrust of the MiG-27's engine. Since it wasn't mounted along the centre of gravity, firing it created a torque that caused the nose to pitch up in much the same way as a pistol tends to rise upwards when fired. There was only one way to avoid this torque, and that was inclining it by more than a degree.

[shiv]

The Hawker Hunter was an designated "FGFA" - a ground attack fighter with four 30 mm cannon for strafing in the lower half of the nose. It (unexpectedly) turned out to be a great interceptor. (The Hunter had a total rate of fire of 80 rounds per sec with 4 cannon of 20 rps each. The GSh 23 twin compares favourably at 60 rps.

I personally don't buy that story about cannon below fuselage for the ground and cannon higher up for air to air combat. Using the same argument aircraft with cannon on one side only - like the Su 30 and F 16 should be less capable of hitting aircraft on the opposite side where there is no cannon - so I believe that theory is a load of crock. I have never head any fighter pilot or Jasjit Singh make any such statements. For a target plane 1000 meters ahead, it hardly makes a difference whether the cannon is 1 meter below or above. The cannon bearing aircraft ideally should have a height advantage or he will be firing upwards and the angle adjustment difference would be minuscule. In any case ranging and targeting is done electronically nowadays.

IIRC the MiG 23s cannon was deadly and could be angled down by a few degrees for strafing.

[SaiK]

If the effective air-air target range for cannons is 2-3 miles/kms max, then leveraging its capability itself a big question. Would not a close combat at these closeness is unthinkable right now?

[Lalmohan]

unless the aircraft is designed around the canon - e.g. A10 or perhaps the Mig 27 then locating the canon is a secondary design objective compared to other critical parameters of the design

many of the 40's and 50's aircraft were indeed designed to be a big gun rack, and some even had canon firing down the middle of the prop shaft (Me109)

[jamwal]

I remember reading somewhere that the legend of A-10 being developed for that canon is not true. The plane was designed 6-7 years before the gun.

[koti]

I think the cannon placement has to do with the ability to fire while pulling up or pushing down in a dog fight.
An interesting thing I found just out is that the GSH-23L can also fire flares.

[shiv]

Dealing with the recoil was the biggest problem. The gun produced a recoil of around 5000 kgf, which was more than half the dry thrust of the MiG-27's engine. Since it wasn't mounted along the centre of gravity, firing it created a torque that caused the nose to pitch up in much the same way as a pistol tends to rise upwards when fired. There was only one way to avoid this torque, and that was inclining it by more than a degree.

Do you have a source for this information? I vaguely recall seeing either a YouTube video or a TV program that said something of the sort - but it seems odd. There are some nice videos of an Indian MiG 27 firing this awesome cannon, and with the gun clearly slung below the axis of the fuselage it probably lies below the center of mass. No matter whether it is in front of or behind the center of mass, it remains below that point and it should cause a nose pitch down and not a pitch up. A revolver pitches up because it is fixed in the hand at the handle while the recoil acts backwards above the point of fixation/fulcrum.

[shiv]

If the effective air-air target range for cannons is 2-3 miles/kms max, then leveraging its capability itself a big question. Would not a close combat at these closeness is unthinkable right now?

1000 meters plus would be the outer limits of engagement. Most descriptions of dogfights with cannon involving India and Pakistan speak of ranges much less than 1000 meters - often closer than 500 meters. Assuming a muzzle velocity 800 meters per sec - there is a time lag of more than one second at longer ranges and a target aircraft can wiggle away in all sorts of ways in one second. Both the predator and prey have to be relatively stable for a couple of seconds to give cannon shells a remote chance of actually hitting the target. That is why a high rate of fire is necessary - a single half second burst should send out a few dozen shells of which at least one should hit.

Aiming at a 5x5 cm stationary target at 10 meters takes about one second. In terms of size a 5x5 cm target at 10 meters is like a 500 cm (5x5 meter) target at 1000 meters. Moving aircraft simply do not provide a convenient 5x5 meter area target to aim at. Head on or from the tail, what one sees is very small. Only when the shooter is above and behind the target aircraft can he get a wide area to aim at in the part just behind the cockpit, with the upper fuselage and wing roots providing a large area for at least one shell to hit. And the whole goddam plane has to be aimed/pointed at the target. If the shooting aircraft is below, then he has to climb - and lose energy and speed and may not be able to close in to a target who is above.

So the conditions required for gun use are very stringent, and agility and power are paramount for both attacker and the target. Problem is that at ranges of 500 meters even close range AAMs could miss so cannons would be a last resort.

When the US and their allies fight anyone - they simply shoot down all opposition at long ranges. In regional conflicts for India this is unlikely so close in dogfights may still occur.

[Kartik]

The Hawker Hunter was an designated "FGFA" - a ground attack fighter with four 30 mm cannon for strafing in the lower half of the nose. It (unexpectedly) turned out to be a great interceptor. (The Hunter had a total rate of fire of 80 rounds per sec with 4 cannon of 20 rps each. The GSh 23 twin compares favourably at 60 rps.

I personally don't buy that story about cannon below fuselage for the ground and cannon higher up for air to air combat. Using the same argument aircraft with cannon on one side only - like the Su 30 and F 16 should be less capable of hitting aircraft on the opposite side where there is no cannon - so I believe that theory is a load of crock. I have never head any fighter pilot or Jasjit Singh make any such statements. For a target plane 1000 meters ahead, it hardly makes a difference whether the cannon is 1 meter below or above. The cannon bearing aircraft ideally should have a height advantage or he will be firing upwards and the angle adjustment difference would be minuscule. In any case ranging and targeting is done electronically nowadays.

IIRC the MiG 23s cannon was deadly and could be angled down by a few degrees for strafing.

exactly. The fighter pilot isn't likely to be taking pot shots at a target a few dozen meters away..else he'd fly into a moving ball of flame within a fraction of a fraction a second. in most dogfights (at least in the modern era, in older times they did get quite close to each other at times) at a fair distance separation, the fire control radar provides the solution for the cannon (something that was lacking in older gen jets, which meant that pilots would try to get closer) taking into account the distance from cannon to target, wind, altitude and hence air density, precisely predicting the path of the cannon projectile. Cannons on fighters or even strike aircraft will not move in elevation or in azimuth, and off-boresight is not a feature.

So the cannon placement on top or bottom of the fuselage hardly matters, as long as the loading is easy and gun gas doesn't get into the intakes and choke the engine.

[srin]

It is explained here (for a Hornet) ... Skip to 2:26 or thereabouts, where the pilot explains the "funnel"


Viewing the rest of the series (this is Mig-29 vs F/A-18), there is a lot of respect shown to the Mig-29's 30mm cannon compared to the 20mm gun of the Hornet.

[Mihir]

Dealing with the recoil was the biggest problem. The gun produced a recoil of around 5000 kgf, which was more than half the dry thrust of the MiG-27's engine. Since it wasn't mounted along the centre of gravity, firing it created a torque that caused the nose to pitch up in much the same way as a pistol tends to rise upwards when fired. There was only one way to avoid this torque, and that was inclining it by more than a degree.

Do you have a source for this information? I vaguely recall seeing either a YouTube video or a TV program that said something of the sort - but it seems odd. There are some nice videos of an Indian MiG 27 firing this awesome cannon, and with the gun clearly slung below the axis of the fuselage it probably lies below the center of mass. No matter whether it is in front of or behind the center of mass, it remains below that point and it should cause a nose pitch down and not a pitch up. A revolver pitches up because it is fixed in the hand at the handle while the recoil acts backwards above the point of fixation/fulcrum.

Sorry, meant to say "pitch down", and not "pitch up". I remember reading it in a magazine article a few years ago. Will try to dig up the source. Also, they did end up inclining the gun, hence the production version did not suffer the pitch down problem, at least not to the point where it was a problem.

[Karan M]

Darn, seeing the public expected specs of IAF and what has been achieved, respect for LCA team. The FOC MK1 will be a handful for sure. Purely based on numbers, they have acheived most of the required capabilities, and this despite really ambitious (read unachievable requirements laid down in the 80's and added to post FSED). Fairly certain once the MK1 achieves FOC, and MK2 tools up, the IAF will order more of this bird.

[Indranil]

Above or below makes no sense at all. But angled up or down does make sense to me.

[srai]

Darn, seeing the public expected specs of IAF and what has been achieved, respect for LCA team. The FOC MK1 will be a handful for sure. Purely based on numbers, they have acheived most of the required capabilities, and this despite really ambitious (read unachievable requirements laid down in the 80's and added to post FSED). Fairly certain once the MK1 achieves FOC, and MK2 tools up, the IAF will order more of this bird.

True.

Even at IOC2, the LCA will be able to fire WVR AAM, drop dumb bombs (100kg & 1,000lb) and LGB w/ Litening Pod, and carry drop tanks. It will have a radar and also come with an EW suite. This is more than what EuroFighter could do at IOC and the Tranche 1 lot (mostly limited to air-to-air role).

At FOC next year, the LCA will be fully qualified with all the weapon systems (WVR/BVR AAM, LGB, bombs, rockets, guns, and drop tanks) the IAF intends it to use. This is a very compressed schedule when you start looking at other more experienced nations building their combat aircrafts where only the subsequent upgraded batches receive a "complete kit".

[Mihir]

Okay, found a link

The Soviet GSh-6-30 aircraft cannon - Denis Evstafyev, edited by Anthony G Williams

despite the reduced ballistics [Ed: from the use of shorter barrels] the recoil force of the GSh-6-30A was about 5,500 kg. The impact loads caused by firing were very high for the aircraft to absorb, particularly as its structure was a development of a light fighter. For ground firing tests the gun was initially mounted on a wooden testbed, but at the first trial firing of the "Shestistvolka" the testbed simply fell apart.

Further problems occurred during the first air firing tests. It was discovered that the impact and frequency characteristics generating by firing the GSh-6-30A on the ground did not correspond to those which took place in the air. The first 25-round burst made in flight was ended by the failure of all of the avionics in the cockpit. In further test flights there were cases of deformation and even tearing away of the nose undercarriage door, and because of the strong vibrations the ammunition feed fell apart. Electronic equipment in an aft-of-cockpit compartment also failed.

To reduce the influence of gun firing on the fuselage, the axis of a gun was inclined downwards 1°13 '. [Ed: this would probably have been to prevent 'pitch-down' on firing.]

[Aditya G]

IIRC I read here on BRF, the recoil effects of the cannon are significantly reduced when the aircraft is in flight.

[Karan M]

Darn, seeing the public expected specs of IAF and what has been achieved, respect for LCA team. The FOC MK1 will be a handful for sure. Purely based on numbers, they have acheived most of the required capabilities, and this despite really ambitious (read unachievable requirements laid down in the 80's and added to post FSED). Fairly certain once the MK1 achieves FOC, and MK2 tools up, the IAF will order more of this bird.

True.

Even at IOC2, the LCA will be able to fire WVR AAM, drop dumb bombs (100kg & 1,000lb) and LGB w/ Litening Pod, and carry drop tanks. It will have a radar and also come with an EW suite. This is more than what EuroFighter could do at IOC and the Tranche 1 lot (mostly limited to air-to-air role).

At FOC next year, the LCA will be fully qualified with all the weapon systems (WVR/BVR AAM, LGB, bombs, rockets, guns, and drop tanks) the IAF intends it to use. This is a very compressed schedule when you start looking at other more experienced nations building their combat aircrafts where only the subsequent upgraded batches receive a "complete kit".

yes..i was also looking through some scrawled notes i had from 2003 from a seminar that talked of LCA ASR etc. what struck me is what was "aspirational" then is now being incorporated into LCA MK1 FOC. and the airframe stuff/basic performance being aimed at was competitive from the airframe POV with the lightest variants of the F-16/Mirage 2000. the LCA ASR IMO was way overambitious. so much so, that on the plus side, even a shortfall with several KPI would still give us a A+ platform today.