LCA: News & Discussions - October 2016

Rishi Verma · Post by **Rishi Verma** » 28 Mar 2017 15:32

shiv wrote:
Rishi Verma wrote:
ShivJi, dont change the subject about shotgun vs rifle (cutting paki in half was an enjoyable graphic) ... But if a bullet exiting the barrel has a kinetic energy of 2000 Joules at the moment, the shooter will feel less than 100 Joules as "recoil",
the rest is dissipated as heat, as gasses escaping, some absorbed by the inertia of the gun.. of course you will keep arguing and i dont get paid to convince you so enjoy...

This is called making a mockery out of physics. Joules is work done. Not force. Did not read the question.

I am sure you can enjoy yourself too if you can stop trying to attract my attention by replying to my posts and putting yourself in a rut with errors that you need to try and wriggle out of like that Paki cut-in-half analogy. Indranil has answered the question that you have wriggled out of answering.

But I have an idea and I will make it easier for you..

Hakim you shoot and scoot does not do justice to your age. You cant read what i write then add terms i didnt use. Gosh your ego is way too inflated but the balloon will pop someday.

You are retired from unrelated field and pooping in forums without a moment of experience in engineering making wild statements and all these years got away. You should continue measuring turn radius of planes with phone video footage or try to guess the colour of sky from a single unknown photo. You are a true comedian, you have no idea how much laughter you are causing.

salaam · Post by **salaam** » 28 Mar 2017 18:01

Rishi Verma wrote:
shiv wrote:
This is called making a mockery out of physics. Joules is work done. Not force. Did not read the question.

I am sure you can enjoy yourself too if you can stop trying to attract my attention by replying to my posts and putting yourself in a rut with errors that you need to try and wriggle out of like that Paki cut-in-half analogy. Indranil has answered the question that you have wriggled out of answering.

But I have an idea and I will make it easier for you..
Hakim you shoot and scoot does not do justice to your age. You cant read what i write then add terms i didnt use. Gosh your ego is way too inflated but the balloon will pop someday.

You are retired from unrelated field and pooping in forums without a moment of experience in engineering making wild statements and all these years got away. You should continue measuring turn radius of planes with phone video footage or try to guess the colour of sky from a single unknown photo. You are a true comedian, you have no idea how much laughter you are causing.

You are mistaken. Hakeem Ji is kept in high regard here, people like you are treated as jokers.

Throwing personal jibes like accent and crookedness of teeth. Some great troll you are. Better spend of your intelligence (lack of) and (short in) effort on MySpace blinking comment pages for 14 year olds.

Admin: regret in advance, but RV needs to be countered.

JayS · Post by **JayS** » 28 Mar 2017 18:20

*deleted - useless post*

hnair · Post by **hnair** » 28 Mar 2017 19:14

Rishi Verma, you are off for a few days. You just had a ban on January. So when you come back, behave. Or it will be permanent

Others, please report! Not respond to flamebaiters

ramana · Post by **ramana** » 28 Mar 2017 22:48

Dileep wrote:Ramana, the spec is in g^2/Hz. One should test at the fundamental and second harmonic, plus a broad band at higher frequencies. This is because there would be a mix of frequencies there due of the resonance of a number of elements.

I haven't figured the unit/dimension of this. Mean while, how much does 1 g^2/Hz feels like? any idea?

Its a mighty kick.

Take a look at how acceleration spectral density is estimated:

https://femci.gsfc.nasa.gov/random/randomequations.html

Khalsa · Post by **Khalsa** » 29 Mar 2017 03:45

ATAGS on LCA thread.
Now I have seen it all.

srai · Post by **srai** » 29 Mar 2017 03:52

Khalsa wrote:ATAGS on LCA thread.
Now I have seen it all.

Maybe Phillip will get his CAS after all

Khalsa · Post by **Khalsa** » 29 Mar 2017 04:00

--post deleted.
aye aye Admins.

ramana · Post by **ramana** » 29 Mar 2017 06:01

Enough baiting each other.

Delete unnecessary posts.

If admin has to do it, warning will be issued.
ramana

Dileep · Post by **Dileep** » 29 Mar 2017 06:42

Thanx for the link Ramana. (OT: Whaddayaknow! the site have a bad security certificate!!)

Imagine 22G spread over just 6 Hz during the burst. That is the kick you will feel.

ramana · Post by **ramana** » 29 Mar 2017 23:28

Dileep, Here is a link to GSh-30-6 in service with FSU Mig-27s. Its 30mm and has 6 barrels.
SU-30 MKI has GSh-30-1 i.e. one barrel.

Shiv also would enjoy the article

http://www.quarryhs.co.uk/GSh-6-30.htm

shiv · Post by **shiv** » 30 Mar 2017 07:24

ramana wrote:Dileep, Here is a link to GSh-30-6 in service with FSU Mig-27s. Its 30mm and has 6 barrels.
SU-30 MKI has GSh-30-1 i.e. one barrel.

Shiv also would enjoy the article

http://www.quarryhs.co.uk/GSh-6-30.htm

Fantastic article - the most detailed one I have read yet. I have an image of this weapon kept on display at Shillong - I will put it up in an appropriate thread. Meanwhile...

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.

Aditya_V · Post by **Aditya_V** » 30 Mar 2017 11:03

Shiv, but I think the twin barrel Gh-23 guns have far less recoil than the Gattling gun of GSH-30, in single barrel it is ok, thats why Su-30 carries far lesser in numbers Ammo for it is gun, even 1 hit to aircraft is pretty lethal. The GSH-30 of Mig-27 is far more powerful than even the A-10's anti tank gun.

I guess Mig-27 pilots fire this gun for a few seconds max, otherwise its lethal for the aircraft, would hate to be in down range of this cannon.

shiv · Post by **shiv** » 30 Mar 2017 12:16

Yes the twin GSh 23 is a well known entity used on our MiG 21 as well an I am confident that it will work fine on the LCA and I have a sneaking suspicion that it will be deadly accurate as well on the Tejas

LokeshC · Post by **LokeshC** » 30 Mar 2017 12:21

Wow. The first thought was it's just a damn gun.

Never thought it would be so complicated. Now I feel like a dumbass for not thinking of what an impulse train can do to a system and its resonance frequencies.

Even if the revoil force is not extreme, if the harmonics of the firing frequency coincides with the resonance frequency of any mechanical subsystem, it will shake loose. And soon you will have everything disintegrating and flying off in every direction.

JTull · Post by **JTull** » 30 Mar 2017 16:50

ramana wrote:Dileep, Here is a link to GSh-30-6 in service with FSU Mig-27s. Its 30mm and has 6 barrels.
SU-30 MKI has GSh-30-1 i.e. one barrel.

Shiv also would enjoy the article

http://www.quarryhs.co.uk/GSh-6-30.htm

Wow!

Anyone know of GSh-30 experience of IAF?

ashishvikas · Post by **ashishvikas** » 30 Mar 2017 20:12

Tejas FOC points on the verge of completion: ADA Chief
# Anantha Krishnan M

http://english.mathrubhumi.com/news/ind ... -1.1832969

JayS · Post by **JayS** » 31 Mar 2017 00:27

Remember the odd looking EFT's for LCA with bulbous front part with slimmer rear part..? During AI-2017 an image was surfaced. That particular shape is to reduce the Aerodynamic interference that the 1200ltr EFTs have on neighboring bombs. The bombs tend to yaw due to this interference. using optimization, ADA could almost remove the effect while increasing some 11% fuel capacity with no increase in the drag counts due to the EFT.

In a ground attack mission the generic fighter aircraft is supposed to carry 1000lb bombs and long range fuel
tanks in addition to routine CCM (Close combat missiles). Typical ground attack configuration of a generic fighter
aircraft is shown in Fig.1(a). For the present configuration of the generic fighter aircraft the presence of a fuel tank
disrupts the normal trajectory of the midboard bomb a shown in Fig.1(b). Initial studies [Ref.1] has shown that the
presence of fuel tank causes a destabilising force on the bomb which results in an undesired yawing and change of
trajectory. Detailed CFD studies [Ref.1,4] has shown that the destabilising yawing moment can be significantly
reduced by reshaping the Inboard fuel tank. This present paper additionally analyses the reshaping of the fuel tank to
reduce pressure drag and maximise fuel for an improved mission performance. All missions computed in this paper is
based on point-mass Aircraft model YAPP [Ref.5] using the aerodynamic and propulsion characteristics of the generic
fighter aircraft including the effects of fuel tank, missiles and bombs

The reshaping studies of an existing 1200lt fuel tank was carried out based on its influence on its
neighbouring bomb trajectory. A parametric model was used to reshape the external fuel tank and evaluated using
Euler PARAS and RANS CFD++ computations. The improvement in mission performance with the reshaped
geometry is 15-18% . The final shapes have 11% additional fuel and trivial sidewash as compared to the existing
1200lt fuel tank.

From the paper: http://www.nal.res.in/cfdsympo/CFD_Full ... 20tank.pdf

JayS · Post by **JayS** » 31 Mar 2017 00:43

The proverbial cliff on the yaw moment wrt side slip angle (Cn_beta) after about 26deg or so of AoA (if you can remember this one from an old paper discussed here quite a few yrs ago) - ADA is trying to tinker with the LCA aerodynamics to extend that angle at which the Cn_beta goes down. They are trying out Nose chin and strakes near the canopy area. Some improvements seen. So don't be surprised to see some strakes on LCA some years down the line. This is the kind of fine tuning I have been expecting and I even mentioned that here a long time ago, that we shall see such fine tuning. Happy to see them doing it.

http://www.nal.res.in/cfdsympo/CFD_Full ... 0chine.pdf

Present day fighter aircrafts have a prominent delta wing configuration for superior manoeuvrability
and enhanced supersonic performance. However the delta wing configuration is prone to severe deterioration in
directional stability (Cnβ, rate of change of yawing moment coefficient with β,(Angle of Side slip)) at high angle of
attack subsequent to the breakdown of the wing vortex. Various slender forebody attachments like strake, mouche,
chines, canard etc., have been studied to show significant improvement in Cnβ at high AOA (Angle of Attack) from
preliminary wind tunnel tests [1,2]. These passive surfaces create a strong initial vortex which primarily energises the
wing vortex and delays its breakdown. In this paper various sensitivity studies of strake and chine were carried out
using RANS computations to understand the coupling effects of strake and wing vortex. This paper analyses in detail
the influence of strake and chine on the pitching and directional characteristics of a generic fighter aircraft.

Preliminary studies on the influence of the strake on a generic fighter aircraft has shown a marked
improvement in Cnβ while degrading Cmy. Various strake geometries has improved Cnβ by energising the wing
vortex but destabilises the pitching characteristics. The design of the best strake with the right compromise of pitching
and directional characteristics has been quite elusive. Therefore subsequent studies were carried out using a chine
(nose strake) to improve Cnβ with a focus on its influence on undesired pitching characteristics. The best chine gives a
marked improvement in Cnβ by anchoring the nose vortex flow with only a marginal effect on pitching coefficient.

JayS · Post by **JayS** » 31 Mar 2017 00:55

Another paper looking at Zero Lift drag with various configurations of SPJ pod and CCM at the outboard pylons:

http://www.nal.res.in/cfdsympo/CFD_Full ... GEMENT.pdf

Drag generated by a particular aircraft configuration plays an essential role in determining the performance characteristics
of an aircraft. Arrangement of the weapons/stores of the aircraft impacts the total drag generated by the aircraft
configuration. An important parameter in quantifying the performance characteristics of an aircraft configuration is the
variation of zero-lift drag, CD0, across the operating Mach numbers. CD0 corresponds to the drag generated by the
aircraft configuration when there is no lift generated. The following configurations are analyzed in this work:

Configuration 1: One CCM at each O/B station of the aircraft
Configuration 2: One CCM and one jammer at the O/B stations of the aircraft
Configuration 3: One CCM and a twin-assembly of CCM and jammer at the O/B stations of the aircraft
Configuration 4: One jammer and a twin-assembly of two CCMs at the O/B stations of the aircraft

The effect of interference drag caused due to the arrangement of weapons is significant at transonic and supersonic Mach
numbers. Configuration 3 and Configuration 4 considered in this work have two CCMs and a jammer in the outboard
station of the wing. But, Configuration 4, which has the two CCMs attached to a single pylon on port side and a CCM on
starboard has lower CD0 predicted across all the Mach number regimes in comparison to Configuration 3 which has one
CCM and jammer connected to a single pylon on port side and a CCM on starboard side. This is due to the difference in
the interference drag generated by the weapons assembly.

JayS · Post by **JayS** » 31 Mar 2017 01:05

A paper talking about optimization of rear fuselage shape to reduce supersonic drag. This one is perhaps for the MK2 version.

http://www.nal.res.in/cfdsympo/CFD_Full ... dy_opt.pdf

Kartik · Post by **Kartik** » 31 Mar 2017 01:38

great finds JayS!

Kartik · Post by **Kartik** » 31 Mar 2017 01:43

JayS wrote:A paper talking about optimization of rear fuselage shape to reduce supersonic drag. This one is perhaps for the MK2 version.

http://www.nal.res.in/cfdsympo/CFD_Full ... dy_opt.pdf

It could be for Mk1A as well.

JayS · Post by **JayS** » 31 Mar 2017 01:45

Could be, yes.

Kartik · Post by **Kartik** » 31 Mar 2017 02:22

JayS wrote:The proverbial cliff on the yaw moment wrt side slip angle (Cn_beta) after about 26deg or so of AoA (if you can remember this one from an old paper discussed here quite a few yrs ago) - ADA is trying to tinker with the LCA aerodynamics to extend that angle at which the Cn_beta goes down. They are trying out Nose chin and strakes near the canopy area. Some improvements seen. So don't be surprised to see some strakes on LCA some years down the line. This is the kind of fine tuning I have been expecting and I even mentioned that here a long time ago, that we shall see such fine tuning. Happy to see them doing it.

http://www.nal.res.in/cfdsympo/CFD_Full ... 0chine.pdf

Present day fighter aircrafts have a prominent delta wing configuration for superior manoeuvrability
and enhanced supersonic performance. However the delta wing configuration is prone to severe deterioration in
directional stability (Cnβ, rate of change of yawing moment coefficient with β,(Angle of Side slip)) at high angle of
attack subsequent to the breakdown of the wing vortex. Various slender forebody attachments like strake, mouche,
chines, canard etc., have been studied to show significant improvement in Cnβ at high AOA (Angle of Attack) from
preliminary wind tunnel tests [1,2]. These passive surfaces create a strong initial vortex which primarily energises the
wing vortex and delays its breakdown. In this paper various sensitivity studies of strake and chine were carried out
using RANS computations to understand the coupling effects of strake and wing vortex. This paper analyses in detail
the influence of strake and chine on the pitching and directional characteristics of a generic fighter aircraft.

Preliminary studies on the influence of the strake on a generic fighter aircraft has shown a marked
improvement in Cnβ while degrading Cmy. Various strake geometries has improved Cnβ by energising the wing
vortex but destabilises the pitching characteristics. The design of the best strake with the right compromise of pitching
and directional characteristics has been quite elusive. Therefore subsequent studies were carried out using a chine
(nose strake) to improve Cnβ with a focus on its influence on undesired pitching characteristics. The best chine gives a
marked improvement in Cnβ by anchoring the nose vortex flow with only a marginal effect on pitching coefficient.

Very interesting. This could, if taken to its conclusion and tested out, increase the Tejas' max AoA to 30 deg.

The concept itself isn't new- nose chine/strake is seen on the Gripen and the MiG-29, whereas fuselage mounted strakes are present on the Mirage-2000. The Mirage-2000's intake mounted strakes were supposedly for the following purpose

1 : improvement of the flying qualities in supersonic flight (downloading of the elevons on the trailing edge, and thus drag reduction).
2 : the small extra lift generated energizes the airflow over the wings at high AoA, improving stability at high AoA

Northrop had applied for a patent for the design of strakes for the T-38, but the intent of that strake was to reduce the landing speed, which makes a lot of sense for a trainer.

Finally, Northrop has demonstrated that a strake of significant size could be attached to the wing of a trapezoidal wing aircraft to extend the operation of the aircraft to higher angles of attack, yielding higher coefficients of lift. In essence such strakes locally extend the wing forward as in a leading edge extension. In the case of the present invention, however, it has been found that by moving the strakes to a position out of the plane of the wing, specifically to a position above the wing just forward thereof, similar increases in the angle of attack and coefficient lift of the aircraft may be achieved, though with improved pitch stability of the aircraft in comparison to the positioning of the same in the plane of the wings.

Kartik · Post by **Kartik** » 31 Mar 2017 02:43

Expect some changes in the LCA Mk2 fin

[url=http://www.nal.res.in/pdf/Publications/LCA.pdf]

Aeroelastic Analysis
Preliminary dynamic and flutter analyses of LCA AF Mk-2 has been carried out in the subsonic, transonic and supersonic regimes.The results obtained have been used for the design modification and static analysis of the modified LCA fin.

LCA Mk2 FEM model. The 0.5m plug aft of the cockpit is visible here.

Kartik · Post by **Kartik** » 31 Mar 2017 04:46

Found this paper that describes the influence of canopy shape on the supersonic drag of the LCA

Influence of canopy shape on the supersonic drag of generic fighter aircraft

Conclusion
The supersonic wave drag characteristics of a generic fighter aircraft was studied initially based on its cross
sectional area distribution. Preliminary Sears-Haack shapes and equivalent body of revolution geometries indicated
significant scope in wave drag reduction. The canopy region was identified for shape modification to reduce drag
and various geometries were studied in RANS solver CFD++ constrained by seat & safety system, structural and
manufacturing requirements to arrive at the best canopy shape. The final modified canopy gave 6% reduction in
supersonic wave drag which translated to 20% improvement in transonic accelerations and 2% improvement in
maximum level speeds. The pitching stability characteristics have improved in the modified fighter which results in
less trim drag. The directional stability characteristics of the modified configuration has deteriorated resulting in
lower cross over alpha which is proposed to be overcome by closed loop feedback control. This modified geometry
also benefits with additional space in the aircraft behind the pilot that can be used to appropriately accommodate
more internal fuel.

Kartik · Post by **Kartik** » 31 Mar 2017 05:06

If you compare the LCA AF Mk2 modified canopy geometry shown in the paper in my previous post, with the latest LCA AF Mk2 image released during Aero India 2017, is the modified canopy geometry apparent?

LCA AF Mk2 from Aero India 2017 brochure

The modified canopy geometry from the ADA paper

Looking at the modified canopy geometry, it becomes apparent that the LCA Navy Mk2 follows the new canopy geometry very closely.

Indranil · Post by **Indranil** » 31 Mar 2017 09:20

When it rains, it pours. Thank you boys!

Kartik · Post by **Kartik** » 31 Mar 2017 10:16

So we can see a host of improvements being planned for the LCA AF Mk2 and very likely, the LCA Navy Mk2. Possible chine and strakes, optimized aft fuselage geometry, modified canopy design and the 0.5m fuselage plug for the AF variant. All of which will go towards reducing drag and improving performance. Combined with all the other improvements in onboard fuel, payload, thrust and onboard avionics, it does look very promising. It is all within reach, that near perfect light fighter that the IAF wants. Really hope the IAF support for the Mk2 program doesn't waver in the face of another single engined fighter..

sankum · Post by **sankum** » 31 Mar 2017 14:02

Thanks JayS and Kartik

shiv · Post by **shiv** » 31 Mar 2017 19:43

shiv wrote: I have an image of this weapon kept on display at Shillong - I will put it up in an appropriate thread.

viewtopic.php?f=3&t=7098&p=2136679#p2136679

Indranil · Post by **Indranil** » 31 Mar 2017 22:19

Okay, with these papers in the open I can talk more openly.
1. They have been working on improving the CnBeta characteristics for a while now. The hull of the LSPs are not particularly uniform and this leads to unstability at higher AoA. All the improvements in LSP 7/8 that you see the smoothening of the air intake for the environment control (at the base of the fin) etc. are related to this. With these improvements they have been able to test fly till 26 degree AoA. Consequently, the in service SPs are limited to 24 degree AoA. They are trying to push it further to 28 degree AoA, enabling them to clear the in service aircraft to 26 degree AoA. At 26 degree AoA, the aircraft will have a minimum speed in tha 185-190 kmph range. This is basically the same as the Gripen. If they can clear Mk1A/Mk2 to 28 degrees, you are looking at something special.

2. Kartik, that LCA-Navy pic is from AI-15. I have been asking folks to show me the pics from AI-17. The Naval LCA will look different. They have retained the wing, but pushed the wing joins outside by about 300 mm on both sides. This allows them to accommodate the straight MLG right next to the air intakes (it retracts kind of to the side and above it). The body plug is 1 meter long instead of the 0.5 mtr of the AF Mk2. Consequently, the nose has developed a chin, very similar to that of the Rafale. They will change the airbrakes too, because the current airbrakes are not suitable for carrier landing. They really considering on making the LEvcon active as well in stead of better maneuverability.

3. Kartik, you are a little late on the canopy optimizations. Me and Jay had a detailed discussion on this before. But you are really the first to notice that the AF-Mk2 does show the new canopy shape!

4. I would love to see the chaff dispensers housed in a better way, than the semi-protruding manner currently employed. It looks like a hack and must be adding to the drag significantly. Another eye sore for me is the current air intake at the root of the fin. They can definitely do better.

5. Otherwise, things are really shaping up well. I kind of wished though that they could consolidate the AF and IN requirements into one aircraft. IMHO AF would love the LCA Navy Mk2 with same shape, but lighter aerostructures. It will reduce design and testing times significantly!

ranjan.rao · Post by **ranjan.rao** » 31 Mar 2017 23:28

http://www.defencenews.in/article/India ... jas-251295

because Modi believes in ‘SAAB ke saath, SAAB ka vikaas’

Although i like the pun, why does everything begin and end with modi in this country?

Kartik · Post by **Kartik** » 31 Mar 2017 23:32

Indranil wrote:Okay, with these papers in the open I can talk more openly.
1. They have been working on improving the CnBeta characteristics for a while now. The hull of the LSPs are not particularly uniform and this leads to unstability at higher AoA. All the improvements in LSP 7/8 that you see the smoothening of the air intake for the environment control (at the base of the fin) etc. are related to this. With these improvements they have been able to test fly till 26 degree AoA. Consequently, the in service SPs are limited to 24 degree AoA. They are trying to push it further to 28 degree AoA, enabling them to clear the in service aircraft to 26 degree AoA. At 26 degree AoA, the aircraft will have a minimum speed in tha 185-190 kmph range. This is basically the same as the Gripen. If they can clear Mk1A/Mk2 to 28 degrees, you are looking at something special.

Could you get confirmation on the strakes and the nose chine for the Mk1A and Mk2? Actually, those design improvements seem small enough to be able to test on the Mk1 in service and introduce it to all SPs.

28 degrees AoA for service jets would mean 2 degrees less than the Rafale, and 2 more than the Gripen C/D/E. Now that would be something!

2. Kartik, that LCA-Navy pic is from AI-15. I have been asking folks to show me the pics from AI-17. The Naval LCA will look different. They have retained the wing, but pushed the wing joins outside by about 300 mm on both sides. This allows them to accommodate the straight MLG right next to the air intakes (it retracts kind of to the side and above it). The body plug is 1 meter long instead of the 0.5 mtr of the AF Mk2. Consequently, the nose has developed a chin, very similar to that of the Rafale. They will change the airbrakes too, because the current airbrakes are not suitable for carrier landing. They really considering on making the LEvcon active as well in stead of better maneuverability.

Did they have a new model of the LCA Navy Mk2 at Aero India 2017? Whatever little I saw through videos indicated that it was the same model displayed at Aero India 2015. And way back after Aero India 2013, I had posted about my conversation with Cmde. Sukesh Nagaraj of ADA, who had mentioned that the fuselage would be widened, thus pushing out the wing joins- the wing span was not being increased directly though. The part about the 1m fuselage length increase for the LCA Navy Mk2 was new to me, and was confirmed by ADA Director Cmde. Balaji at this AI-2017. From my post on BRF back then-

- The widening of the fuselage will push out the wings a bit, thus increasing wing span. Otherwise no increase in wing span as such. It doesn’t need it, since the wing area is massive already

- On the N-LCA Mk2 they will change the position of the landing gear and bring it more towards the wing/fuselage joint. The landing gear will then retract into a fairing for that. That will also free up space in the fuselage for additional fuel

I really badly want to see the final designs of the LCA Navy Mk2 and the LCA AF Mk2! I wish someone could pull a scoop on those, since ADA seems unlikely to publicize these.

3. Kartik, you are a little late on the canopy optimizations. Me and Jay had a detailed discussion on this before. But you are really the first to notice that the AF-Mk2 does show the new canopy shape!

I seem to have missed those discussions on the canopy optimization- any link to that discussion?

This was the first time I saw it but the gains in drag reduction and improvement in transonic acceleration seem big enough to port these changes to the Mk1A variant. But that doesn't seem to be happening, or at least we haven't yet heard of that.

ADA hasn't released 3 view CAD renderings of the LCA AF Mk2 for whatever reason. There are more images of the AMCA floating around than the in-detail design LCA AF Mk2 for some reason. Would be great if someone like Ananth Krishnan could write a detailed article on the LCA AF Mk2 with good images showing the changes. Not sure why ADA is being so coy about that.

4. I would love to see the chaff dispensers housed in a better way, than the semi-protruding manner currently employed. It looks like a hack and must be adding to the drag significantly. Another eye sore for me is the current air intake at the root of the fin. They can definitely do better.

5. Otherwise, things are really shaping up well. I kind of wished though that they could consolidate the AF and IN requirements into one aircraft. IMHO AF would love the LCA Navy Mk2 with same shape, but lighter aerostructures. It will reduce design and testing times significantly!

The air intake at the root of the fin is already an improvement on the earlier design. From the renderings we've seen, it seems like they're not changing that. As for the AF and Navy having the same primary design, I'd agree, except maybe for the landing gear. Even a lighter and smaller MLG located in the same position as that for the LCA Navy Mk2 would probably be heavier than the fuselage housed MLG currently, with a bigger extension of the oleos. On the flip side, that might free up some space in the fuselage for fuel tanks, ala Gripen NG/E.

Prasad · Post by **Prasad** » 01 Apr 2017 00:36

There was a CAD model too. I'll see if I can dig that one out.

Kartik · Post by **Kartik** » 01 Apr 2017 01:03

Thank you Prasad! More images would be very welcome! The model displayed for the LCA AF Mk2 doesn't seem to show the smoothening out of the canopy as shown in the papers that were presented, or the CAD rendering that was shown in the ADA brochure and the image you posted

Any chance you have more views of the LCA AF Mk2 CAD rendering? Would be of great help in figuring out the changes.

Kartik · Post by **Kartik** » 01 Apr 2017 01:08

Am in seeing things, or is that a nose chine right at the base of the pitot probe on the LCA Navy Mk2 model?? That would be as per what the ADA paper on strakes suggested was an improvement for improving Cn beta at high AoA.

JayS · Post by **JayS** » 01 Apr 2017 01:28

Indranil wrote:
2. Kartik, that LCA-Navy pic is from AI-15. I have been asking folks to show me the pics from AI-17. The Naval LCA will look different. They have retained the wing, but pushed the wing joins outside by about 300 mm on both sides. This allows them to accommodate the straight MLG right next to the air intakes (it retracts kind of to the side and above it). The body plug is 1 meter long instead of the 0.5 mtr of the AF Mk2. Consequently, the nose has developed a chin, very similar to that of the Rafale. They will change the airbrakes too, because the current airbrakes are not suitable for carrier landing. They really considering on making the LEvcon active as well in stead of better maneuverability.

There you go. If there was a direct upload option to BRF I would have done it ages ago.

As you can see the NLCA MK2 looks really weird from below. This 1.0mtr plug and outboard wing movement etc is known for over a year in public now, I suppose. I always wonder why they just don't go for same airframe for AF and Navy version in MK2. Since there is really no constrain that AF should have to accept leaner NLCA MK2. Plus it would have even more fuel internally for AF and much better performance with lesser empty weight.

JayS · Post by **JayS** » 01 Apr 2017 01:34

Kartik wrote:
Am in seeing things, or is that a nose chine right at the base of the pitot probe on the LCA Navy Mk2 model?? That would be as per what the ADA paper on strakes suggested was an improvement for improving Cn beta at high AoA.

No nose chin.