Advanced Medium Combat Aircraft (AMCA) News and Discussion

[BnglrTester]

Our forces must be having a hearty laugh every time these gamechanging articles come out, must be the highlight of their evening when they retire to their barracks etc 🤣 At least they n we can go to bed smiling. Thank you admin for your sense of humour 🙏

Like they had a hearty laugh when they embarassed all of us by shooting off a cruise missile, shoot down their own colleagues mistaking it for a missile, or got shot down in enemy territory?
The forces are not ealiens. They come from our own and has got the same flaws.

 

[POTATO MAN123]

How exactly do you detect things behind mountains??

 

[Bhartiya Sainik]

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.

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:

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.

 

[Bhartiya Sainik]

I mentioned about DRAG where people panic a lot. We should dive little more into it.

Drag are of many types

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

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.

(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.

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.

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

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

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.

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.

 

[Bhartiya Sainik]

@team @WebMaster
(https://defence.in/search/2461/?q=AMCA&c[title_only]=1&o=date)
20 threads of AMCA.😱
BTW emoji not working properly.

 

[pramodkumar.ca]

Even my grandchildren will not see the AMCA in action. It will be admired forever. While other nations will have 8th-generation fighter jets, we will proudly showcase our 5th-generation aircraft.

incapable DRDO and inefficient HAL would kill this project forever

 

[Bhartiya Sainik]

Even my grandchildren will not see the AMCA in action. It will be admired forever. While other nations will have 8th-generation fighter jets, we will proudly showcase our 5th-generation aircraft.

incapable DRDO and inefficient HAL would kill this project forever

Other than GTRE, it is difficult to find out where the bottleneck is - Govt., IAF, ADA/NAL, etc.
DoD + IITs have made some appreciable progress like RAM, radar, EW sensors, etc but lagging in other design aspects & components like engine, DAS, etc.
May be there are some type of problems everywhere, multiple bottlenecks.

 

[Bhartiya Sainik]

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.

There were some sheets also, somewhere on social media.

 

[Bhartiya Sainik]

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

---------------------------------------------------------------------------------------------
Harshal Pal

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Kuntal Biswas

Older design

Revised design

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Ankur Singh Chauhan

 

[Bhartiya Sainik]

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.

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.

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.

 

[Bhartiya Sainik]

Will AMCA have Towed Decoy?

 

[Bhartiya Sainik]

A collage of diagrams of EW antennas, GPS, SATCOM, Radar altimeter, TACAN, RWR, IFF, VHF/UHF, L-band, data link (IFDL/MADL).

The diagrams say "preliminary" so final positions may change.

The following is collage of F-22's & F-35's sensors & antennas:

 

[Bhartiya Sainik]

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.

 

[Bhartiya Sainik]

I don't have an official refined infographic or static model yet. Possible locations & coverage sectors for DAS/MAWS:

 

[Bhartiya Sainik]

SENSOR FUSION
It came with 5gen jets helping pilot to focus on 1 picture of battle space, coming from multiple sensors as part of the jet or from wingman, other friendly jets, AWACS, satellite, ground asset, etc.

RWR was a standard among 4gen jets, but with analog wide sector indicators. I guess no jet had spherical sensor coverage & narrow direction indicator of incoming missile or enemy jet locked on to us.
Thereafter moresensors were added - RF/EW/ESM/IFF, IR/MAWS, LWR.
It became important even for MLUed 4.5gen jets to have spherical coverage & some degree of sensor fusion with digital display.

Demo cockpit of AMCA has been shown at Aero-India expo. The static model has 1 wide primary MFD & 2nd MFD below it b/w legs.

The actual inducted jet will have a sensor fused view.
But this demo cockpit may not be showing it yet. In lower right coner we see RWR & stores display.
The main 4 bigger sections, from left to right -
- Digital gyroscope/attitude indicator
- Navigation display with map
- Radar/Attack display
- Multiple systems - Fuel, Hydraulics, Electrical, Nozzle position, Anti-ice, Engine RPM % bar,
--------------------------------------------------------------------------------------------------

Another pic:

The RWR has been enlarged on the right.
Navigation display remains at 2nd from left.
Radar/Attack display has been moved below to bottom row.
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Navigation & RWR displays
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2nd from left is navigation+map display.
Below it are RWR & Radar/Attack displays.
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AFAIK the 5gen jets F-22, F-35 & others too, do not care anymore about individual displays like RWR, IRST sweeping, radar sweeps & AESA beams, passive ESM finds, etc. All those things become processing overhead for pilot & for display GPU, hence fused into 1 situation display.

As the AMCA project progresses, we hope to see better version of demo cockpits, more precise, showing sensor fused display.