AMCA - Advanced Medium Combat Aircraft (HAL)

Okabe Rintarou

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This one.
The numbers are great.
This material seems nice in application to some select areas maybe, but its manufacturing process is very difficult. Very difficult to scale this up for mass production. But they me be actually trying to use this because I recently read in some document that they are trying to build large area graphene sheets. I'll try to find about it.
 

Lonewolf

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Its possible that this radar absorbent material gets used on AMCA. It absorbs X-band radar waves, which is used by most fighter jets. Also absorbs radar waves from Ku band, which is used by most BVR Air-Air and Surface to Air missiles. Will be difficult for an enemy fighter to track or get a lock on AMCA. Read last line of the paper: "Thus BaF-CB-PVA nanocomposite films will be useful in stealth applications".

There have been other types of radar absorbent materials posted in this thread before, including ones from iron ball paints to Jaumann absorbers. We aren't sure which ones will finally be used on AMCA, so we try to keep track of all research being done in this area, especially by DRDO.
Can't they use different for different parts ?
 

Dark Sorrow

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Its possible that this radar absorbent material gets used on AMCA. It absorbs X-band radar waves, which is used by most fighter jets. Also absorbs radar waves from Ku band, which is used by most BVR Air-Air and Surface to Air missiles. Will be difficult for an enemy fighter to track or get a lock on AMCA. Read last line of the paper: "Thus BaF-CB-PVA nanocomposite films will be useful in stealth applications".

There have been other types of radar absorbent materials posted in this thread before, including ones from iron ball paints to Jaumann absorbers. We aren't sure which ones will finally be used on AMCA, so we try to keep track of all research being done in this area, especially by DRDO.
The main question is whether such material air worthy.
It will have to go through lot of stress testing, flutter testing and vibration testing before it can be treated air worthy. Its IR signature also needs to identified during flight.
Effects of vibration, stress and flutter on RF-attenuation also need to identified.
What about effect of S-band and L-band radars?
 

Okabe Rintarou

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The main question is whether such material air worthy.
It will have to go through lot of stress testing, flutter testing and vibration testing before it can be treated air worthy. Its IR signature also needs to identified during flight.
Effects of vibration, stress and flutter on RF-attenuation also need to identified.
What about effect of S-band and L-band radars?
True. Which is why we likely won't know which ones will get selected. But looking at all this R&D should at least give us some confidence that we even have options to chose from.

As I understand it, for longer wavelength bands like L band, you can't really do anything because L band wavelengths lead to resonance with smaller structures like canted vertical stabilizers, unlike X-band wavelengths where the phenomena is optical and hence can be reduced with RAM and shaping. F-35 and F-22 are hence vulnerable to L band, as will be AMCA. Whereas larger airframes like those of stealth bombers B-2 or B-21 can have stealth against L band if they have no small features that can cause resonance and have the right materials.
 

Okabe Rintarou

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For anyone interested, the F-35's RAM is a Carbon Fiber Reinforced Polymer (CFRP) where the carbon fiber has carbon nanotubes bonded with it.

This material, they claim, is effective against everything. From 0.1 MHz to 60 GHz. That is almost every radar band from HF, VHF, UHF, L, S, C, X, Ku, K, Ka and V bands.

They vary the CNT length and density as well as orientation of fibers and depth of RAM layer to tune the absorption characteristics for effectiveness against particular bands. My guess is they tune it to achieve maximum stealth against X and Ku bands for the exact material they used in the F-35.
 

Ajax01

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For anyone interested, the F-35's RAM is a Carbon Fiber Reinforced Polymer (CFRP) where the carbon fiber has carbon nanotubes bonded with it.

This material, they claim, is effective against everything. From 0.1 MHz to 60 GHz. That is almost every radar band from HF, VHF, UHF, L, S, C, X, Ku, K, Ka and V bands.

They vary the CNT length and density as well as orientation of fibers and depth of RAM layer to tune the absorption characteristics for effectiveness against particular bands. My guess is they tune it to achieve maximum stealth against X and Ku bands for the exact material they used in the F-35.
But the NAL hybrid metamaterial itself gets above 90% in 1 to 60 Ghz at just 1.6mm. This is possibly vastly superior to the F35 one. But then again this one is 20 years later tech than the F35 one so maybe that is justified.
 

Okabe Rintarou

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But the NAL hybrid metamaterial itself gets above 90% in 1 to 60 Ghz at just 1.6mm. This is possibly vastly superior to the F35 one. But then again this one is 20 years later tech than the F35 one so maybe that is justified.
Its superior in RAM performance no doubt. But structurally and by ease of manufacturing its inferior. F-35's RAM is a CFRP. It doesn't get more robust than that.
 

Okabe Rintarou

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AMCA ram is probably already selected, so they may have overcome these obstacles or went ahead with something else. I also found a really nice wideband transparent radar absorber by IIT K guys they possible can use those in the canopy.
Link?
 

Ajax01

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This one:
They are trying out some packaging as well on this.
They also have a 99% absorption ITO based one, dunno if its transparent or not:
 

Ajax01

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How you came to this conclusion?
Look at the article a few pages back. This Nal Hybrid material absorbs more than 90% of incoming radar waves in 1 to 60 Ghz whilst being 1.67 mm thick. LM signature control material needs to be tailored to a specific frequency bands via orientation of CNTs etc etc. And is much much thicker. This is of course assuming this is used in the F35.
 

Dark Sorrow

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Look at the article a few pages back. This Nal Hybrid material absorbs more than 90% of incoming radar waves in 1 to 60 Ghz whilst being 1.67 mm thick. LM signature control material needs to be tailored to a specific frequency bands via orientation of CNTs etc etc. And is much much thicker. This is of course assuming this is used in the F35.
Which article are you referring to? Can you post the link.
 

rodeo

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Hello
I'm from Turkey. If you've been following Turkey's defense sector, you'd know Turkey is developing a fifth-gen fighter too. I find AMCA interesting because it's similar and the timelines of the project is close to ours and I'm trying to learn more about it. If you'll allow me to give a quick info about Turkish TFX,

-It's a multi-role, all-weather, stealth fighter jet developed by TAI and BAE Systems as subcontractor.
-It has a max take off weight of 27.215kg
-length: 21m, wingspan: 14m, height: 6m
-engine: prototypes and the first few squadrons will use F110 engines until national engine is developed.
-timelines:
2023 - roll-out from hangar
2025 - first flight
2028/2029 - first deliveries

If you have questions, please ask. I'm here to learn. It may take a bit time for me to answer, because I might need to do some reading about the questions but nevertheless that's the goal.
 

UnderFingy

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Hello
I'm from Turkey. If you've been following Turkey's defense sector, you'd know Turkey is developing a fifth-gen fighter too. I find AMCA interesting because it's similar and the timelines of the project is close to ours and I'm trying to learn more about it. If you'll allow me to give a quick info about Turkish TFX,

-It's a multi-role, all-weather, stealth fighter jet developed by TAI and BAE Systems as subcontractor.
-It has a max take off weight of 27.215kg
-length: 21m, wingspan: 14m, height: 6m
-engine: prototypes and the first few squadrons will use F110 engines until national engine is developed.
-timelines:
2023 - roll-out from hangar
2025 - first flight
2028/2029 - first deliveries

If you have questions, please ask. I'm here to learn. It may take a bit time for me to answer, because I might need to do some reading about the questions but nevertheless that's the goal.
Post introduction here.

TF-X discussion here
 

rodeo

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Post introduction here.

TF-X discussion here
Thanks. I posted the same to that thread.
 

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