ADA AMCA - Advanced Medium Combat Aircraft

Gautam

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Feb 16, 2019
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Does not having a mid-rib bang in the centre of an already cramped IWB limit your choices of weapons? Since it essentially partitions the IWB into two halves. Wouldn't it have been better to mount the hydraulic piping on the IWB roof scattered around the weapons mounts (& do away with the mid rib) to be able to fully utilize the space on offer? Surprisingly, even F-22 & J-20 suffer from the same "compromise":
My guess is that without the mid-rib the bay doors would have to be locked on to each other. It is difficult to achieve positive locking between 2 movable surfaces especially with drag on the bay doors. It takes a longer & it would also require very complicated locking mechanisms.

The opening-closing-positive locking cycle for the AMCA's IWB is supposed to be <2 seconds. That would be very hard to achieve without the mid-rib. Of course opening the bay of a stealth fighter increases the RCS, so you would want the cycle time to be as low as possible.

Just a guess.
 

Bhartiya Naagrik Sainik

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Dec 20, 2021
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It would be good if AMCA can deploy this kind of DAS sensors.
The F-35's DAS was able to detect plume of rocket/missile 1300 Kms away (in clear weather). The AESA radar & other antennas also supplement this process hence we call it sensor fused avionics.

1640163941564.png


When our phone cameras have reached 200MP 8K resolution with photo/video processing functions, then military optical sensors are much ahead.
The F-35's DAS sensor performs multiple functions with 360 degree coverage in X-Y-Z axis:
> IRST
> MLD/MAWS
> Night/thermal sight
> Low altitude navigation
> Aiding in GMTI (Ground Moving Target Indication)
> Aiding in target ID & classification
It has left the traditional IRSTs far behind which required to mechanicaly move, took time to sweep sector & performed limited functions.
It is like the PESA version of IRST.
Distributed Aperture means multiple sensors across the jet's body giving all round coverage.
This started with the F-22's AN/AAR-56 sensors which are also distributed in 6-axis. But the F-22 didn't implement EOTS/IRST due to stealth reasons & X-35 JSF/CALF program was also started in early 1990s.
1640164525020.png

1640166115809.png


In F-35 also the concept of distributed apertures followed with the AN/AAQ-37 sensors positioned in the same 6-axis like in F-22.

1640164004643.png
1640164022255.png
1640164176236.png
1640164047867.png


The AN/AAQ-40 EOTS was added under chin rather than a separate external pod or as a portruding pod like in F-16 AFTI.
The EOTS as the name suggests is not just a Targetiing System for LGBs but can also perform functions mentioned in above points.

1640164116482.png
 

Bhartiya Naagrik Sainik

Active member
Dec 20, 2021
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🤣 Just have fun

Afterwards they use an adhesive putty i think to blend with the surface.
However, closeup pics of finished F-22 & F-35 also have some special type of bolts/rivets which don't show the filled putty blended.

1640328131077.png

1640328042250.png

1640328259292.png


IDK if USA & Russia may have tested RCS of airframe with different screw & bolt caps, how much difference it may have created in RCS.

1640328411697.png
 

_Anonymous_

Senior Member
Dec 4, 2017
17,337
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Mumbai
Afterwards they use an adhesive putty i think to blend with the surface.
However, closeup pics of finished F-22 & F-35 also have some special type of bolts/rivets which don't show the filled putty blended.

View attachment 22218
View attachment 22216
View attachment 22219

IDK if USA & Russia may have tested RCS of airframe with different screw & bolt caps, how much difference it may have created in RCS.

View attachment 22220
Buddy , this is a thread for AMCA not the raptors or PAK FA. Pls locate them in the appropriate section.
 
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Bhartiya Naagrik Sainik

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Dec 20, 2021
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Buddy , this is a thread for AMCA not the raptors or PAK FA. Pls locate them in the appropriate section.
I put it here bcoz AMCA will also be 5th gen & perhaps we can improve over these things. Wait for my future posts, i will prove my point.
Actually the post is incomplete, i should have mentioned AMCA with some of its pics to corelate & compare.
 

Valhalla

Member
Dec 22, 2021
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India
LCA airframe is an absolete design of 4th gen. Just using composites is not enough. 5th gen jets have completely different characteristics.
5th generation is also composites only, no?

LCA achieves stealth not by shaping but by small size. In the end the result matters, not the means- an LCA will light up on the enemy radar much later than probably every other fighter in current IAF inventory. And it has a relatively large nose to boot which will soon pack a home grown GaAs AESAR. Look first, shoot first. Can carry BVR missiles- would be my pick for offensive ops in many scenarios. Certainly no reason to be dismissive of its capabilities.

To study the advantages of small jets you can read up about IAF exercises where they deployed Su-30s and migs. Or why the F-16 being small and nimble could run circles around bigger aircraft besides being hard to spot even visually.
 

Sathya

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Dec 2, 2017
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5th generation is also composites only, no?

LCA achieves stealth not by shaping but by small size. In the end the result matters, not the means- an LCA will light up on the enemy radar much later than probably every other fighter in current IAF inventory. And it has a relatively large nose to boot which will soon pack a home grown GaAs AESAR. Look first, shoot first. Can carry BVR missiles- would be my pick for offensive ops in many scenarios. Certainly no reason to be dismissive of its capabilities.

To study the advantages of small jets you can read up about IAF exercises where they deployed Su-30s and migs. Or why the F-16 being small and nimble could run circles around bigger aircraft besides being hard to spot even visually.

Big nose got wasted because of lack of power.
 
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Valhalla

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Dec 22, 2021
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Big nose got wasted because of lack of power.

Not talking about geopolitical equations or even compatibility with LCA's engine plumbing (for which a suitable adapter may be constructed as was done when we switched the Kaveri for F404) or even cost. Is there any other engine in the whole world from any other make that makes more power AND fits in the belly of the LCA? ie has to have dimensions similar to the F404 (length/dia/airflow etc)- I know the M88-2 is compatible (was swapped for F404 on Rafale) but makes way lesser power- and also does not have the redundant systems expected in a jet engine designed for single-engine planes.

For reference here are the specs of the F404:

1640440881400.png
 
Last edited:

Bhartiya Naagrik Sainik

Active member
Dec 20, 2021
78
109
India
5th generation is also composites only, no?

LCA achieves stealth not by shaping but by small size. In the end the result matters, not the means- an LCA will light up on the enemy radar much later than probably every other fighter in current IAF inventory. And it has a relatively large nose to boot which will soon pack a home grown GaAs AESAR. Look first, shoot first. Can carry BVR missiles- would be my pick for offensive ops in many scenarios. Certainly no reason to be dismissive of its capabilities.

To study the advantages of small jets you can read up about IAF exercises where they deployed Su-30s and migs. Or why the F-16 being small and nimble could run circles around bigger aircraft besides being hard to spot even visually.
We should not shift PoV from 5th gen to 4th gen in a forum for 5th jen jet like AMCA. LCA should not be discussed here or comapred to AMCA.

But to answer your statements only, from 5th gen PoV, LCA does not achieve stealth at all. Not even any other delta-wing jet 4.5gen like Grippen, Rafale, EF-2000, J-10. All they can do is have strong EW suite. Composites, AESA, EW are not enough. If small missiles can be detected then what is a size of j4.5gen jet compared to missile?
Yes, LCA may have lesser RCS than other jets in IAF but that's not proper comparison for RCS w.r.t 5th gen characteristics. Take the example of F-22:
> There cannot be any 90 degree or spherical, cylindrical type of surfaces from sides & front.
> Internal weapons bay is a must.
> There cannot be any portruding blade antennas, which have to be replaced by blended surface antennas.
> Even the air inlets & ventilation grills have to be given stealth treatment.
> RAM has to be applied at appropriate places
> The canopy has to be single piece with coatings like Indium Tin Oxide, etc.
> Surface discontinuities & bumps have to be minimum.
> Many antennas have to be un-directional rather than omni-directional.
> Stealth jet nozzle use very special techniques on reducing IR signature.

I'm not really fan of light jets at all, they loose fuel soon & have less load. In my opinion for proper mileage & damage to foe done per sortie, a jet fighter has to be medium size minimum.
F-16 is agile jet but obsolete in front of 5th gen jets. But among 4th gen also the image of an Air Superiority Fighter revolves around bigger jets like F-15, Su-35 or at least medium jet like EF-2000, Rafale. So F-16 cannot win against Su-35, upgraded Su-30MKI in dogfight bcoz of TVC.
LCA's turning radius is huge, if it tries to pull more then it will stall bcoz it is a simple delta jet like Mirage-2000, etc. Every wing & airframe design has its limits.
 
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AbRaj

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Dec 6, 2017
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-----------------
Was thinking about navy s plan for TEDBF,
They utilize technology developed for MWF like cockpit, canard etc
Whatever developed for Amca like nose cone, stealthy avionics twin engine configuration etc
N Lca in creating facilities /trainer upfront.
And also have Rafale M for benchmark ( by any chance)

Due to complexity of operations, they ll go less risky , proven technology to have the safe margin for any optimization.

Tedbf is using the entire aviation R&D work done so far.
Wonderful planning.
I believe it ll make surprise entry like LCH...
IMO TEDBF is a totally different airframe design and will require a lot of work
Not talking about geopolitical equations or even compatibility with LCA's engine plumbing (for which a suitable adapter may be constructed as was done when we switched the Kaveri for F404) or even cost. Is there any other engine in the whole world from any other make that makes more power AND fits in the belly of the LCA? ie has to have dimensions similar to the F404 (length/dia/airflow etc)- I know the M88-2 is compatible (was swapped for F404 on Rafale) but makes way lesser power- and also does not have the redundant systems expected in a jet engine designed for single-engine planes.

For reference here are the specs of the F404:

View attachment 22233
He is just assuming. Gripen A/B/C/D use same engine and carry much bigger radar and more EW equipments than LCA.
PS-O5
68769D6C-D3DA-45AE-A0E5-87D8AC9AF7D2.jpeg
1DCB11CE-5CB5-412F-8302-9B3826961355.jpeg

AESA in C/D
64E93AB5-81E7-46E8-B63C-F56DDA259FF0.jpeg
9C48B1E4-0F47-43BE-9D03-72EA44C5F873.jpeg
 
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Bhartiya Naagrik Sainik

Active member
Dec 20, 2021
78
109
India
It would be good if AMCA can deploy this kind of DAS sensors.
The F-35's DAS was able to detect plume of rocket/missile 1300 Kms away (in clear weather). The AESA radar & other antennas also supplement this process hence we call it sensor fused avionics.

View attachment 22185

When our phone cameras have reached 200MP 8K resolution with photo/video processing functions, then military optical sensors are much ahead.
The F-35's DAS sensor performs multiple functions with 360 degree coverage in X-Y-Z axis:
> IRST
> MLD/MAWS
> Night/thermal sight
> Low altitude navigation
> Aiding in GMTI (Ground Moving Target Indication)
> Aiding in target ID & classification
It has left the traditional IRSTs far behind which required to mechanicaly move, took time to sweep sector & performed limited functions.
It is like the PESA version of IRST.
Distributed Aperture means multiple sensors across the jet's body giving all round coverage.
This started with the F-22's AN/AAR-56 sensors which are also distributed in 6-axis. But the F-22 didn't implement EOTS/IRST due to stealth reasons & X-35 JSF/CALF program was also started in early 1990s.
View attachment 22191
View attachment 22195

In F-35 also the concept of distributed apertures followed with the AN/AAQ-37 sensors positioned in the same 6-axis like in F-22.

View attachment 22186View attachment 22187View attachment 22190View attachment 22188

The AN/AAQ-40 EOTS was added under chin rather than a separate external pod or as a portruding pod like in F-16 AFTI.
The EOTS as the name suggests is not just a Targetiing System for LGBs but can also perform functions mentioned in above points.

View attachment 22189

----------------
1640449243649.png


For designing a new gen jet, the AMCA team may have to do experiments with measuring heat signature at different altitudes bcoz air density affects engine performance, atmospheric scattering, etc. And also in different spectrum of LWIR, MWIR, SWIR, UV.
Whichever engine will be chosen, it has to be flown with intended nozzle design for measurements.

USAF had/has Portable Seeker/Sensor/Signature Evaluation Facility (PSSSEF) to dosuch studies.
Below are some examples of how USAF measured exhausts of various jets at different altitudes, nozzle settings, angles & orientations, even flare release.

Here we have an F-15 with ATIMS III & TIGER pods to measure IR signatures.
Airborne Turret Infrared Measurement System III (ATIMS III)
Threat Infrared Generic Emulation Radiometer (TIGER)


1640449321698.png
1640449392090.png


Below we have F-18 with the TIGER pod

1640449442457.png
1640449466437.png


Below we have F-15 with SARIS pod.
Spectral/Spatial Airborne Radiometric Infrared System (SARIS)


1640449517668.png
1640449545441.png


Below we have UH-60 with ARMS pod
Airborne Radiometric Measurement System (ARMS)


1640449576668.png


There are some other pods like
Beam Approach Seeker Evaluation System (BASES)
Calibrated IR/visible/UV Ground and Airborne Radiometric Spectrometer (CIGARS)
Supersonic Airborne Tri-Gimbal Infrared System (SATIRS)
Stabilized Electro-optical Airborne Instrumentation Platform (SEAIP)
 

Sathya

Senior member
Dec 2, 2017
2,706
1,600
India
IMO TEDBF is a totally different airframe design and will require a lot of work

He is just assuming. Gripen A/B/C/D use same engine and carry much bigger radar and more EW equipments than LCA.
PS-O5
View attachment 22235View attachment 22236
AESA in C/D
View attachment 22237View attachment 22238

Not assuming .

Mk1A has bigger radome but lesser TRMs than mk2.
Mk2 radome size is reduced while increasing the TRMs.
Aircraft is also overweight.

Saw the interview in which DDR guy was asking the question s.
 

AbRaj

Senior member
Dec 6, 2017
2,490
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Republic of Wadiya
Not assuming .

Mk1A has bigger radome but lesser TRMs than mk2.
Mk2 radome size is reduced while increasing the TRMs.
Aircraft is also overweight.

Saw the interview in which DDR guy was asking the question s.
It has nothing to do with engine thrust limitations. You should know that Mk-2 TWR is even lower than Mk-1/1A despite higher thrust engine. Same is true for Gripen E compared to A/B/C
PS: I believe it has something to do with LRU packaging and space management for cooling system requirements. Although I’m not sure.
 

AbRaj

Senior member
Dec 6, 2017
2,490
1,829
Republic of Wadiya
----------------
View attachment 22239

For designing a new gen jet, the AMCA team may have to do experiments with measuring heat signature at different altitudes bcoz air density affects engine performance, atmospheric scattering, etc. And also in different spectrum of LWIR, MWIR, SWIR, UV.
Whichever engine will be chosen, it has to be flown with intended nozzle design for measurements.

USAF had/has Portable Seeker/Sensor/Signature Evaluation Facility (PSSSEF) to dosuch studies.
Below are some examples of how USAF measured exhausts of various jets at different altitudes, nozzle settings, angles & orientations, even flare release.

Here we have an F-15 with ATIMS III & TIGER pods to measure IR signatures.
Airborne Turret Infrared Measurement System III (ATIMS III)
Threat Infrared Generic Emulation Radiometer (TIGER)


View attachment 22240View attachment 22241

Below we have F-18 with the TIGER pod

View attachment 22242View attachment 22243

Below we have F-15 with SARIS pod.
Spectral/Spatial Airborne Radiometric Infrared System (SARIS)


View attachment 22244View attachment 22245

Below we have UH-60 with ARMS pod
Airborne Radiometric Measurement System (ARMS)


View attachment 22246

There are some other pods like
Beam Approach Seeker Evaluation System (BASES)
Calibrated IR/visible/UV Ground and Airborne Radiometric Spectrometer (CIGARS)
Supersonic Airborne Tri-Gimbal Infrared System (SATIRS)
Stabilized Electro-optical Airborne Instrumentation Platform (SEAIP)
Nice yaar. Your posts generally are very informative and I enjoy reading them.
Same is true about @wolf..... (the guy with longest name)
 

Valhalla

Member
Dec 22, 2021
13
15
India
It has nothing to do with engine thrust limitations. You should know that Mk-2 TWR is even lower than Mk-1/1A despite higher thrust engine. Same is true for Gripen E compared to A/B/C
PS: I believe it has something to do with LRU packaging and space management for cooling system requirements. Although I’m not sure.

Similar observation in the hornet > super hornet transition. Bigger engine does not mean faster! Bigger means more ordnance, flying farther, staying airborne longer.

1640506482558.png



 
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AbRaj

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Dec 6, 2017
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Republic of Wadiya
Similar observation in the hornet > super hornet transition. Bigger engine does not mean faster! Bigger means more ordnance, flying farther, staying airborne longer.

View attachment 22251


Hay Big Name guy, post the full text of the link in F35 (or Rafale) section and see the fun. It’s very informative anyway and quite relevant when comparing design choices made by LM F35 and DA Rafale design teams . In our case it’s equally true for AMCA and TEDBF.
And coming from a highly decorated Lead Test Pilot of USN, it carries immense weight.
 
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