ADA AMCA - Advanced Medium Combat Aircraft

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What a hilarious tech bro take. Even russians and chinese choose the same hardware. Its the most suitable and commercially available and common sensical choice. This is not desi uncle's laptop which he uses to watch porn. Its not even connected to internet. Btw, the entire US Military runs on Windows the must vulnerable operating system.
Do you have ANY idea how many ways malware can be injected? EVEN in airgaped systems? Please, do not comment on what you dont know a shit about. It does not matter if a computer is not connected to internet. There are million ways to introduce malware and million more ways to trigger and control it. Whats worse is, they are using intel processors in which blobs of mircocode with no ways finding what that microcode does.

Also, do you have any source that Russians and Chinese are using same hardware in their planes? I highly doubt they are.

And precisely, this is NOT a desi uncles laptop and thats why they should be choosing hardware which they can control better.

Oh, and US military is highly compartmentalised. It uses many seemingly obscure and custom technologies in critical roles for a reason. There is a reason why a completely obscure language like Ada finds so much traction in US military.

Arre these are prototype works, hardly the final frozen config.
There is a saying in engineering that prototypes becomes final product as soon as deadline approaches. And given how badly managed timelines on Indian defence engineering works usually are, these are indeed going to become final product.
All military grade software is tweaked accordingly, so intel/windows all are fine!
You put lipstick on a pig, its still a pig.
 
Do you have ANY idea how many ways malware can be injected? EVEN in airgaped systems? Please, do not comment on what you dont know a shit about. It does not matter if a computer is not connected to internet. There are million ways to introduce malware and million more ways to trigger and control it. Whats worse is, they are using intel processors in which blobs of mircocode with no ways finding what that microcode does.

Also, do you have any source that Russians and Chinese are using same hardware in their planes? I highly doubt they are.

And precisely, this is NOT a desi uncles laptop and thats why they should be choosing hardware which they can control better.

Oh, and US military is highly compartmentalised. It uses many seemingly obscure and custom technologies in critical roles for a reason. There is a reason why a completely obscure language like Ada finds so much traction in US military.


There is a saying in engineering that prototypes becomes final product as soon as deadline approaches. And given how badly managed timelines on Indian defence engineering works usually are, these are indeed going to become final product.

You put lipstick on a pig, its still a pig.
You think scientists, users and entire security Council is fool.
 
You think scientists, users and entire security Council is fool.
Yes. I worked for Intel for few years, worked in the team that designed perhaps the first processor they really designed in India from scratch (search for project Whitefield on google, which got cancelled due to messy Indian taxation laws and Intel's paranoia). I am an IIT grad and sure as hell know more about this than these "experts".

This is not really a typical weapons design choice, it is a question of hardware system design. For something like this, any modern Intel processors is a very poor choice. They should go with a processor and accelerator they have better control of instead of these off the shelf parts. Even if they want to go with off the shelf parts, they should get one which is not having as many blackboxes. Something like Power9 will be a better choice, even if they get the entire chip off the shelf. With open design (low level RTL design + more) and spec, they can validate the chip for all security related scenarios. Power9 is also very performant and scalable design and has been implemented using 14 nm processes. Way better than anything Intel can offer.
 
ADA stuff.

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AGENDA - AMCA's SUPERCRUISE

Different people speculate AMCA to Supercruise b/w Mach 1.2-1.4 with F414 engines & Mach 1.5-1.6 with JV engine producing 75 KN dry thust.

> On one side we have Mother Nature's unbeatable laws of PCM putting limits of performance - higher drag, higher KE required, higher complexity design.
> On the other side we have global engineers pushing for Speed (both cruising & maximum) -
Turboprop -> Turbojet/fan -> Ramjet -> Turbo-Ramjet -> Variable cycle adaptive engine
> KE required increases as square of velocity, looks like panic🙀, but comes from Calorific value of researched fuels with secret sauce 🍛& ingredients - small volume but big kick👢, especially after compression.
> Currently SuCr is attached to Turbo-jet/fan, considered an "overkill", inefficient, gimmick, etc by many as per Performance studies on engine types. Some would say it is war-time mode/feature which it is.
But if nations're already prepared to do it in war-time since 3 decades & will continue in future also then what can civillians do?

Supercruise provides ability to -
- launch weapons to have higher range w/o increasing IRS of jet.
- Intercept targets better.
- Evade enemy's weapon.
1721467258089.png

In peace time, fighter jets fly subsonic due to multiple reasons -
- Sonic booms disturbs residential areas.
- Fuel efficiency. Typically, less/more throttle means less/more fuel flow means less/more thrust/speed/distance flown.

Jet engines like Turbo-jet/fan have their efficiency boundaries but still since decades scientists & engineers are working on better airframe design & engine to use same amount of fuel but achieve higher thrust/speed/distance travelled.

> Given any engine with an inlet diameter, it is upto designer how much thrust can be squeezed out. Engineers either do not know that limit or it is above top secret.
> 2 same jets with different wing & fuselage design but with same # & type of engine(s) will have different performance.


If we take 3 Supercruising jets - F-22 (SuCr M 1.8), Rafale (SuCr M 1.4), EF-2000 (SuCr M 1.5) & their engines F119, M-88-2, EJ-200 & compare with F414 then it is very difficult to find governing reason resulting in max dry thrust bcoz there are many permutations & combinations of individual engine parts design & performance.
I created a graph, manipulating the values up/down to bring the graph lines closer to visually compare better:
1721467025414.png

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We see that -
> Turbine inlet temp. is a very low slope line. It takes a dip with EJ-200.
> Inlet diameter, inlet area, engine weight, volume, air mass flow show identical increasing trend.
> But, Engine length, dry thrust, dry T/W ratio, dry T/Vol ratio, Bypass ratio take a dip with F414.
So the big dip in Bypass ratio might have impacted dry thrust & then dry T/W ratio, dry T/Vol. ratio. I wonder if engine length also influenced it.
> # of compressor & turbine stages take a dip with EJ-200. This could have affected compression ratio also.
> F119's # length, inlet dia/area, body volume, weight, air mass flow jumps obviously.
But # of stages, compression ratio, fuel SFC, take a BIG dip but impacting its dry T/W & T/Vol ratios
STILL its dry thrust is like DOUBLE.🤠🤩

Fuel consumption
is measured in units like g/KN/s or lb/lbf/hr, called SFC or Specific Fuel Consumption. But different people can use different metrics like fuel used as per airframe weight, distance travelled, etc.

F-22's F119 engine's SFC with inlet dia. 100cm at 100% power (116-120.3 KN) is around 17 g/KN/s.
2 engines, so F-22 SFC is 34 g/KN/s at 100% power & Sup.Cr. Mach 1.5-1.8 (514.5-617.4 m/s).
So 3.94-4Kg/s fuel for covering 514.5-617.4 m/s or 128.6-156.7 m/Kg or 6.38-7.77 gm/m.
Empty weight 19.7 T + 50% fuel 4.1 T + full IWB 8 AAMs 1.1 T = 24.9 tons
Airframe T/W ratio at 100% power = 2x(116 to 120.3)/9.8 /24.9 = 0.94 to 0.98
Fuel per ton = (3,940-4,000)/24.9 = 158.23-160.64 gm/s/T.
50% fuel 4.1 tons while supercruise will be depleted in 1,025-1040 seconds or 17-18 minutes covering 527-642 Kms.


GE F-414 engine's SFC with inlet dia. 79cm at 100% power (57.8-61.83 KN) is 20.5-23.25 g/KN/s depending upon model. 75 KN JV engine is planned.
2 engines, so AMCA SFC will be 41-46.5 g/KN/s at 100% power.
So 2.37-2.87Kg/s fuel will be used.
AMCA empty weight 12 T + 50% fuel 3.25 T + 4 Astr MK3 SFDR 0.88 T = 16.13 tons
T/W ratio at 100% power = 2x58/9.8 /16.13 = 0.73
Fuel per ton = (2,370-2,870)/16.13 = 146.93-177.92 gm/s/T.
let's assume that with 0.73 T/W AMCA can also supercruise at M 1.2 (411.6 m/s).
50% fuel 3.25 tons while on supercuise will be depleted in 1,132-1,371 seconds or 18-23 minutes covering 466-564 Kms.

When new engine with 75 KN dry thrust will be available then hopefully 6 AAMs will be carried.
T/W ratio at 100% power = 2x75/9.8 / (16.13 + 0.44) = 0.92
Then hopefully AMCA will supercruise around M 1.5



Rafale's M-88-2 engine's SFC with inlet dia. 70cm at 100% power (50KN) is 22.14 g/KN/s.
2 engines, so Rafale SFC is 44.28 g/KN/s at 100% power & Sup.Cr. Mach 1.4 (480.2 m/s).
So 2.21 Kg/s fuel for covering 480.2 m/s or 217.28 m/Kg or 4.6 gm/m.
To go this extra 59 m/Kg-fuel Vs F-35, the SFC is increased from 20.3 to 22.14 g/KN/s.

EF-2000's EJ-200 engine's SFC with inlet dia. 74cm at 100% power (60 KN) is 21-23 g/KN/s.
2 engines so EF-2000 SFC is 42-46 g/N/s at 100% power & Sup.Cr. Mach 1.5 (514.5 m/s).
so 2.52-2.76 Kg/s fuel for covering 514.5 m/s or 186.41-204.16 m/Kg or 4.9-5.36 gm/m.

So we see that Rafale with empty design weight 8.5 T, 492 sqft clipped delta wing & 50KN engine can supercruise at M 1.4
but F-18E/F with empty design weight 14.5 T, 500 sqft. trapezoidal wing & 58 KN engine cannot due to 6T weight increase due to carrier-ops MLG & other things & higher drag wing.
 
I mentioned about DRAG where people panic a lot. We should dive little more into it.

Drag are of many types
1721973476401.png

Some drag increase with speed & some decrease, but total drag increase.
1721974062997.png

That's why most people panic even before calculating. Why the world is pushing for increasing cruise & max speed?

The propulsion performace of Turbo-fan is limited around Mach 1.6 aspergraph below. Yet we see F-22 SuCr at M 1.8 with F119 engnes whose SFC is lowest 17 gm/N/s at 100% throttle. So there is definitely something(s) classified.
1721972796592.png

(File:Specific-impulse-kk-20090105.png - Wikimedia Commons)
(File:Gas turbine efficiency.png - Wikimedia Commons)

That means if military is persistent on SuCr then we civillians are stuck with something somewhere, perhaps with engine efficiency & drag graphs are bothering us too much, while there are structural factors also.

We should keep in mind that objective, priorities of military & civil jets are different.
MoD & Air force also have budget & SOP for peace time Ops incl. pre-planned routes, responses,flight altitude, speed kkeping in mind min. fuel expenses, maintenance & spares charges, etc.
But design focuses on war time performance also.

Let's look at the collage of drag, the highlighted part of graph in green color.
Real world is not ideal but full of resistance, losses, still as wing sweep angle increases, the drag decreases drastically.
Coefficient of drag Cd & Fd Force of drag are different, just like (Cf=u) coefficient of ground friction & (F=u.M.g) ground friction force.

1721973404342.png


So just like ground force equation (F - Mg = Ma), we need Flight equation of motion. As per the scope of forums, we common people enthusiasts don't need complex 3-axis equation including roll, pitch, yaw, like Navier-Stokes equation, etc. But this kind of forum has to go on for 1-2 decades at least.
Let's take a basic example of level flight. Make corrections/alterations where you like.

1721973442242.png


But for our low IQ minds, we need a simplified formula for overall drag - The Drag equation

1721973509679.png


1721973534877.png

Fd increases as square of Velocity🙀, but
the Cd of swept wing jet is 0.02 +/-
Air density at cruise altitudes is < 1 Kg/M^3. At 30Kft it is 0.458, at 50kft it is 0.186


NOTE - Make corrections/alterations as required.
Drag Force Equation Fd
= (1/2) (Air density X Cd X Cross Section Area X Velocity^2)
Air density
@ 40,000 feet = 0.3 Kg/m^3
Coefficient of drag Cd for wing sweel angle around 50 degrees = 0.02
Speed let's consider Mach 1.2 (411.6 m/s, round down to 410 m/s) which is considered bad for SuCr
Cross Section Area of AMCA at wingtip level, let's say = 8 m^2
1721973616709.png

Fd = (0.3 X 0.02 X 8 X 410 X 410)/2 = 4,034.4 N = 4.034 KN
If 2 F414 engines together produce 2x58 KN = 116 KN dry thrust
then net thrust = T - Fd = 112 KN, it is like an engine with 56 KN dry thrust
It is analogous to 116 people are pulling something forward & 4 people are trying pull behind.
Net result is 112 pulling forward. This is simple theoretical level-flight example. I am curious to know actual values.

GE F-414 engine's SFC with inlet dia. 79cm at 100% power (57.8-61.83 KN) is 20.5-23.25 g/KN/s depending upon model. 75 KN JV engine is planned.
2 engines, so AMCA SFC will be 41-46.5 g/KN/s at 100% power.
So 2.37-2.87Kg/s fuel will be used.
AMCA empty weight 12 T + 50% fuel 3.25 T + 4 Astr MK3 SFDR 0.88 T = 16.13 tons
T/W ratio at 100% power = 2x58/9.8 /16.13 = 0.73
Fuel per ton = (2,370-2,870)/16.13 = 146.93-177.92 gm/s/T.
let's assume that with 0.73 T/W AMCA can also supercruise at M 1.2 (411.6 m/s).
50% fuel 3.25 tons while on supercuise will be depleted in 1,132-1,371 seconds or 18-23 minutes covering 466-564 Kms.

When new engine with 75 KN dry thrust will be available then hopefully 6 AAMs will be carried.
T/W ratio at 100% power = 2x75/9.8 / (16.13 + 0.44) = 0.92
Then hopefully AMCA will supercruise around M 1.5

Those who want deeper dive can include laws like conservation of momentum/energy/mass; equations of Navier-Stokes, Bernouli, Laplace, Euler, etc; Reynold's number, Critical Mach number, Stagnation pressure, etc, etc.

Practically the avionics computer of modern jet fighter is equivalent of compacted average Super-computer calculating many 3D equations every millisecond.
Computing power is measured in units like MIPS - Millions Instructions/Second & FLOPS - Floating Point Operations/Second).

So we see that real world physics will always have resistance but overall effect matters & as per that solutions or work-arounds are developed. Supercruise is war time feature & it will be used for reasons mentioned. The variable cycle engine will extend its usage.
 
Traditionally, the hinged door configuration with actuators is used which protrudes outside, thus experiencing the drag force. In the present study, an innovative sliding door operating mechanism is devised such that doors slide within the internal weapon bay and are minimally exposed outside.
View attachment 26240
View attachment 26241

Not a good idea bcoz while moving it is occupying space of IWB in lower corners of IWB & will strike the fins of weapons.
If we trace the locus of the door then it looks similar to that of a stick or ladder sliding down :
1722965047151.png

If we imagine this locus superimposed on IWB shown by ADA then it is clearly not feasible.
1722965100062.png

Not even with folding fin weapons.

Not just that, even if the IWB door width is reduced half resulting in 4 doors total, imagine the tandem IWBs of Su-57 in parallel, then also the doors opening internally will strike the weapons.
I am using edited Su-75 cross-section to depict the scenario :
1722965155674.png

NOTE - the circular cross-section weapon above is not the current BVR-AAM like Astr, Meteor but bigger diameter weapon with folding fin, A-A or A-G.
Better solution would be to have these doors open outwards like in Su-57.
1722965198076.png
 
AGENDA - RAM (Radar Absorbent Material) for AMCA.

This is old news now. Our DoD organisations with some IITs have developed RAM paints, sheets named "Adrishya", "NiRaLa", etc, composite materials & working on geometric shaping starting with AMCA.
The RCS results would obviously be top secret.

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There were some sheets also. I don't have their pics.
 
There were some color pics. I don't remember where i saw, Twitter or other forum.
Holy Grail is now CNT skin with broadband frequency absorption properties like F-35's skin which can absorb frequencies as low as 0.5GHz all the way upto 60GHz. That in itself is far better than any paint or spray and less maintenance inducive. And thankfully we've already developed such fibre-mat skin🙂
 
Before we talk further on shape, structure, RCS, etc of AMCA further, let's have a look of 3D CAD designs made by 5 people i have spotted so far :
1- Murli Yadav (social media ID not available)
(defenceforumindia.com/members/jon-arts.18541/)
2- Ankur Singh Chauhan (x.com/Anx450z)
(DFI - defenceforumindia.com/members/wahmanrespector.37183/)
3- Kuntal Biswas (x.com/Kuntal__biswas)
(defenceforumindia.com/members/16257/)
4- Satwik Sadhukhan (x.com/i_m_satwikk)
5- Harshal Pal (x.com/HarshalPal5)
(defenceforumindia.com/members/31984/)

If anyone of you know them & other artists including international ones, please invite them here.

I will post only selected pics, rest can be checked on their Twitter, DFI, etc posts. Some are also present on 3D sites like Turbosquid, Artstation, Sketchfab, Behance, etc.
===========================================================
Murli Yadav
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--------------------------------------------------------------------------------------------------------
Satwik Sadhukhan
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---------------------------------------------------------------------------------------------
Harshal Pal
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------------------------------------------------------------------------------------------------
Kuntal Biswas

Older design

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Revised design

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---------------------------------------------------------------------------------------------------
Ankur Singh Chauhan
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SHAPE OF AIRCRAFT, CHANGE IN ORIENTATION, AREAS OF APPLICATION OF RAM
In war time, Fighter jets might plan a sortie waypoints as per fixed assets like airbases, SAMs, terrain, etc. So the jet can maintain flight at certain altitude & heading to have minimum RCS towards certain areas.
1724478531530.png


But the dynamic assets like moving ground SAMs, AWACS, enemy fighter jets can force to tactically alter the plan, waypoints & maneuver in roll, pitch, yaw axis which increases RCS towards certain angles.
1724478540059.png


The 5gen jets still use rudders but canted at angle matching the fuselage side wall. from the diagrams above, on rolling & banking, the surface area at that angle increases a lot for few seconds. The entire body is reflecting some RF energy.
This may compel to apply RAM on entire ventral/bottom side.

Earlier in capitalist country like USA, private companies developed their version of RAS & RAM whose quality would differ & cost of application & maintenance would be very high. Special machines would be needed to wrap the jet with RAM tapes, attach RAm panels, or paint the RAM.
Today multiple nations have developed their own RAS, RAM with easier application & reduced cost.

But bcoz of nature of RF radiation is not simple, & ultimately a fighter jet has to do so much maneuvering, sometimes to evade enemy jets & missiles, that RAM may have to be applied almost everywhere. So people usually prioritise only front RCS but side, top, back RCS now would become equal priority.
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AMCA Vs TFX Kaan Vs KF-21, top view, side view, front view, isometric/corner view, as per present state of designs.
Good AMCA diagrams are not yet available, even by CAD artists.
Turkey was given F110-GE-129 engine. India was offered F-16IN with F110-GE-132A engine. We can't go for older airframe designs but if the business was done for the engine then we could have designed a jet better than AMCA.

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