AMCA - Advanced Medium Combat Aircraft (HAL)

Bhartiya Sainik

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@Bhartiya Sainik brethen what is the size of IWB of amca. I have heard it will carry rudram 1 internally for that iwb will need to be large enough around 5.5m long. Is that true
That's 50% increase in length & 300-375% increase in weight of 600 Kg :shock::eek1: comapred to 12-13' long BVR-AAMs weighing 160-220 Kg. Where exactly did u hear that? I don't communicate with DoD people. I'm not journalist. IDK.
It is not impossible but in my low IQ understanding then it will need folding fins, AMCA will become AHCA & its looks will change. No heavy jet has done it so far - F-22, Su-57, J-20. Then how can medium jet do it?
The following pic of Su-30MKI carrying Brahmos AShM, Rudram-1 ARM & Astr AAM is clear evidence why we need AHCA with IWB versions of all types of weapons.
1719817562634.png

If Rudram is called NG-ARM then we need N2NG-ARM (Next to Next Gen ARM) :laugh::pound: something like AGM-88G AARGM-ER. On January 12, 2024, Lockheed Martin was awarded a contract to integrate its modified version with all three F-35 variants.
1719819969077.png


For now, just think -
62' long F-22 can carry only 12' long AIM-120, AMCA fuselage is identical to F-22's.
65' long Su-57's IWB is 14.4' long. The 2 tandem IWBs are not joined otherwise it could have carried Novator & some ARM, AShM, cruise missiles.
Neither of them expanded their IWB for ARM, AShM.
For 58' long AMCA to carry 18' long AGM in IWB, the depth/height of IWB will also increase affecting the arrangement of other components changing the shape of fuselage, wings, a new jet basically.
Considering all the 3D & 2D art available on internet, the expo models, it doesn't seem so.
1719833842082.png


AMCA is just 4 feet shorter than F-22 & with identical fuselage so i'll take example of F-22.
Although many electrical, mechanical, electronic parts have been made compact, light BUT there are certain things which cannot be miniaturised, modified or bypassed like -
- air intake tunnel
- engines
- internal fuel tanks with good capacity
All other components are surrounding the above components.

1719761673914.jpeg


Just behind the IWB are various components already shown in diagram above like cooling system, heat exchangers, pumps, reservoirs, additional sensors & electronics, (also some secret stuff causing export ban).
So if the IWB is extended backwards then all those components will have to shift sideways, upwards, downwards causing the rear fuselage to bulge out but there is an aeronautical engineering design parameter called "Whitcomb Area rule" implimented on F-22 & hence most probably on AMCA also.
1719820193751.png

We can see how the fuselage narrows down towards rear after IWB

If the engine get pushed up causing hump it might look like YF-23

1719762642046.jpeg


You can separate the engine gap to create longer IWB like in Su-57 but no jet in peace time patrol regularly carries big heavy weapons affecting fuel economy & military budget, except for excercises. Nobody has to be that ready all the time. And like i said earlier SU-57 did not join the tandem IWBs. There are some old diagrams on internet for Su-57 weapons options, size comparison, with folding fins also.
1719813807628.png


A similar design difference of lateral Vs tandem bays was seen for Mitsubishi F-3 iterations. Now it seems to be merged with Tempest to create GCAP. We have to wait & see about its weapons bays.
1719825493418.png

If the entire IWB is extended backwards then wing tips will also shift backwards & new structure will look like fictive FB-22
1719764562206.jpeg

1719766575805.jpeg


Similarly AMCA will become ALBA (Advanced Light Bomber Aircraft) :laugh:o_O:bplease::facepalm::hehe:
 

Satish Sharma

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I heard from none other than a youtuber who claimed 4 rudram in iwb. It could be modified rudram. Ig..
Btw join defenceforumbharat.com
 
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Bhartiya Sainik

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I heard from none other than a youtuber who claimed 4 rudram in iwb. Guess who :creepy:
:hmm:
Well, i have seen many Youtubers - Defence Matrix, Alpha Defence, Defence Squad, Indian Defence Updates, Indian Defence Analysis, Indian Defence News, Delhi Defence Review, Nitin Gokhale with Bharat Shakti, Shiv Aroor & Vishnu Som with NDTV, Amit updates, Defence Decode, Tarmak Media House, etc.
:drool::fyeah:
 

Satish Sharma

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:hmm:
Well, i have seen many Youtubers - Defence Matrix, Alpha Defence, Defence Squad, Indian Defence Updates, Indian Defence Analysis, Indian Defence News, Delhi Defence Review, Nitin Gokhale with Bharat Shakti, Shiv Aroor & Vishnu Som with NDTV, Amit updates, Defence Decode, Tarmak Media House, etc.
:drool::fyeah:
I'm talking about alpha defence
 

Bhartiya Sainik

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:hmm::confused1:
F-22 with 2x156-165 KN engines carry max 1.37 tons in IWB (2x AIM-9 + 2x AIM-120 + 2x 450kg JDAM).
AMCA with 2x110 KN engines want to carry 2.4 tons in IWB. :shock: :nono:
Astr MK1 - 154 Kg, 12.5' long, 18cm diameter.
Astr MK3 SFDR - 220 Kg, 12'8" long, 20cm diameter, 60cm wingpan.
Rudram-1 - 600 Kg, 18' long, 32cm diameter, 95-100cm wingspan, 150 Km range.
AM-88G AARGM-ER - 361 Kg, 14' long, 25cm diameter, 110cm wingspan, 300 Km range. I guess it will be shortened further.
IDK how much front+rear clearance exactly is left, say 1 ft.
ADA has said that internal load is 1.5 tons with 98 KN wet thrust. If 110 KN engine is developed for FOC AMCA then in same T/W ratio IWB capacity will be 1.68 tons, divideby 4 = 421 Kg. So Rudram length will also have to reduce by roughly 2/3rd to 12 ft. Aeronautical engineering calculations may not be so simple unitary method, so someone has to ask bluntly upfront to DRDO/HAL/ADA guys.
Alpha Defence said -
> folding wings, ok we are on same page. It has to be like Kh-58 for Su-57
1719840375960.png

1719840653388.jpeg

Above each missile occupies width of approx. 51cm.

> AMCA will have bigger/longer IWB than F-35 = agreed, Astr MK3 SFDR will need 14' long IWB like Su-47.
If T/W ratio has to be maintained with 4 Rudrams then Rudram has to be roughly 12' long, 420 Kg, similar to AGM-88E AARGM-ER.

Now for the lateral dimensions, let's consider Astr MK3 SFDR with 20cm dia. & folding wings like shown above in diagram. With 5cm lateral clearance on both sides, missile will occupy 30cm width. For 3 AAMs 90cm width IWB is required.
For 2 Rudrams in each L+R IWB 90/2=45cm width will be available which will suffice for 32cm dia. Rudram with folded fins keeping 6.5cm lateral clearance on both sides, provided Rudram should be 12' long & 420Kg to maintain T/W ratio.

I cannot imagine AMCA or any 5th gen medium jet, not even J-31/35, with fuselage identical to F-22, to have 19-20 feet long IWB carrying 4x(18' long 600Kg) missiles with 2x98-110KN engines,
But ADA quotes external load of 5 tons with 3 hard-points per wing, I giuess only 4 such missiles of total 2.4 tons can be carried externally. Outer most pylon will be for lighter AAM.

I can imagine AMCA or any 5th gen medium jet with to have 16' long IWB with 2x(15' long missile weighing roughly 500 Kg) if either
- engines get pushed up creating hump looking like YF-23
- engines are separated & central IWB is created like in Su-57 or Mitsubishi F-3(24-DMU).
 

BON PLAN

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Supercrusie is cruising at 1.1Mach (greater than speed of sound) or higher when in flat trajectory. While descending, almost any plane can go fast without afterburner. Nevertheless, my point is that speed above 0.9Mach causes extraordinary air drag which increases exponentially as speed increases. This means speed of 1.3Mach would consume 2 times as much fuel as 0.8Mach for same distance eve without using A/B
The word "supercruise" was not invented my me, and the definition is not mine. Ask Lockeed Martin.

It is fuel less greedy to reach mach 1.3 without after burner that with an after burner, because the specific consumption in dry is far smaller.

In the F35 case, it is only able to go beyond mach 1 thanks to AB, and to maintain it without AB only in slight descent. Why? Because it was not studied as a fighter, but to replace F16 and A10 in the CAS role, and accordingly it is shaped as a sugar piece.
 

Bhartiya Sainik

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The word "supercruise" was not invented my me, and the definition is not mine. Ask Lockeed Martin.

It is fuel less greedy to reach mach 1.3 without after burner that with an after burner, because the specific consumption in dry is far smaller.

In the F35 case, it is only able to go beyond mach 1 thanks to AB, and to maintain it without AB only in slight descent. Why? Because it was not studied as a fighter, but to replace F16 and A10 in the CAS role, and accordingly it is shaped as a sugar piece.
In last 10 pages members have discussed SUPERCRUISE, Fuel consumption & F-35 performance. The engine performance Vs airframe performance is a very very tricky thing, especially with 5th gen IWB concept.

F-35 is an intentional blunder bcoz of export, otherwise why export ban on F-22 even for allies?

Supercruising is not about just squeezing out thrust from engines but also aerodynamic shaping of jets, lifting body, variable cycle engine, inlet geometry control, pressure recovery & air flow management, etc.
NOTE - Afterburner thrust & MTOW are not required to consider. 50-70% fuel & std. A-A load is used.
An immediate benefit is range of AAMs & ARMs. Higher the launch altitude & velocity, higher the missile rage. At certain altitude where a particular engine gives max supercruise w/o revealing IR signature by afterburner, will give certain range to missiles, higher will be NEZ (No Escape Zone).

1720019674266.png

While launching missile, Supercruising jet has better chances to conceal IR signature compared to afterburner using jet.
While evading missile also there are strategies & tactics to dodge leading/lagging hit-point missile, where Supercruise at M 1.8 will be very effective consecutively comapred to other jets using afterburner & losing fuel rapidly.

Someone wrote that Supercruise is not efficient due to exponential increase in transonic wave drag & fuel will rapidly get depleted, which is correct but the drag rapidly decreases also after Mach 1.
1719945860420.png

So ideally an aircraft should supercruise beyond Mach 1.8 at least. The danger zone is 0.9 to 1.5

Also, there is the "Whitcomb Area Rule" to shape a fuselage of jet to reduce the drag. Supersonic Area rue also there as per which the aircraft body need to be within the Sonic-Cone. These rules are being used in almost all jets i think. there could be more rules which we civilians enthusiasts may nor know yet.

Another reason cited is it needs an excessively powerful engine which means its fuel efficiency will be lowered compared to using a smaller engine. There is no rule like this, especially with upcoming variable cycle engines. Higher bypass ratio engines are bigger with better fuel efficiency. In my limited knowledge IDK if we have any formula to calculate thrust & fuel required at 100% level, given the dimensions & weight of engine. Engine thrust/weight ratio & fuel consumption varies. 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.

The parameters which influence thrust & fuel economy of engine are all of its design parameters & operating conditions -
- Compression or Pressure ratio - how much air can be compressed
- with how many fan, low pressure, high pressure compressor stages.
- Air mass flow per second
- combustor design
- Turbine inlet temperature
- # of high & low pressure stages
- Afterburner design
- Bypass ratio
- fixed/variable cycle engine


In theory there is a formula F=Ma = M(Vout-Vin) where V is air velocity at intake & exhaust.
But practically, how fast will a jet go at 100% power depends on
- airframe weight at the time
- engine design
- altitude (air density), friction force.
- airframe design producing certain amount of lift & drag due to friction & shockwaves.
- special feautures like shock compression lift.


2 same jets with different wing & fuselage design but with same # & type of engine(s) will have different performance.

Different sources give different data on Supercruise
For example F-22,
1720019942873.png


Fuel consumption is measured in units like g/KN/s or lb/lbf/hr, called SFC or Specific Fuel Consumption.

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.

F-35's F-135 engines SFC with inlet dia. 109cm at 100% power (128.1 KN.) is around 20.3 g/KN/s.
Sup.Cr. M1.2 (411.6 m/s).
So 2.6 Kg/s fuel for covering 411.6m.s or 158.3 m/Kg or 6.31 gm/m.
But to go this extra 30m/Kg-fuel Vs F-22, the SFC is increased from 17 to 20.3 g/KN/s.
F-35A Empty weight 13.3 T + 50% fuel 4.15 T + 4 AAMs 0.6 T = 18.05 tons
Airframe T/W ratio at 100% power = 128.1/9.8 /18.05 = 0.72
Fuel per ton = 2,600/18.05 = 144.04 gm/s/T.

So we see that F135 engine has more thrust but higher SFC than F119 engine,
& F-35 goes further /Kg fuel, consumes less fuel per unit distance, per ton of body BUT has lower T/W ratio and cannot supercruise.


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.
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

NOTE - Among these 3 engines F414 is smallest engine with highest SFC at 100% power.
NOTE - IDK what is the SFC of these engines at say Mach 0.7 & what is the throttle position. I think these kind of parameters are secret. Sometimes these fiigures are calculated at full IWB load, sometimes AA load + 50%-80% fuel dpending upon fuel left after reaching 35-40K feet altitude & supercruise speed.

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.


Now after knowling fuel used, distance traversed per second at Supercruising speed with 100% thrust level, if people can obtain the same data at say Mach 0.7-0.8, then merit/demerit of Supercruise can be debated.

But the R&D to increase speed, distance travelled in minimum fuel used will never stop.
 
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Bleh

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In last 10 pages members have discussed SUPERCRUISE, Fuel consumption & F-35 performance. The engine performance Vs airframe performance is a very very tricky thing, especially with 5th gen IWB concept.

F-35 is an intentional blunder bcoz of export, otherwise why export ban on F-22 even for allies?

Supercruising is not about just squeezing out thrust from engines but also aerodynamic shaping of jets, lifting body, variable cycle engine, inlet geometry control, pressure recovery & air flow management, etc.
NOTE - Afterburner thrust & MTOW are not required to consider. 50-70% fuel & std. A-A load is used.
An immediate benefit is range of AAMs & ARMs. Higher the launch altitude & velocity, higher the missile rage. At certain altitude where a particular engine gives max supercruise w/o revealing IR signature by afterburner, will give certain range to missiles, higher will be NEZ (No Escape Zone).

View attachment 259598
While launching missile, Supercruising jet has better chances to conceal IR signature compared to afterburner using jet.
While evading missile also there are strategies & tactics to dodge leading/lagging hit-point missile, where Supercruise at M 1.8 will be very effective consecutively comapred to other jets using afterburner & losing fuel rapidly.

Someone wrote that Supercruise is not efficient due to exponential increase in transonic wave drag & fuel will rapidly get depleted, which is correct but the drag rapidly decreases also after Mach 1.
View attachment 259585
So ideally an aircraft should supercruise beyond Mach 1.8 at least. The danger zone is 0.9 to 1.5

Also, there is the "Whitcomb Area Rule" to shape a fuselage of jet to reduce the drag. Supersonic Area rue also there as per which the aircraft body need to be within the Sonic-Cone. These rules are being used in almost all jets i think. there could be more rules which we civilians enthusiasts may nor know yet.

Another reason cited is it needs an excessively powerful engine which means its fuel efficiency will be lowered compared to using a smaller engine. There is no rule like this, especially with upcoming variable cycle engines. Higher bypass ratio engines are bigger with better fuel efficiency. In my limited knowledge IDK if we have any formula to calculate thrust & fuel required at 100% level, given the dimensions & weight of engine. Engine thrust/weight ratio & fuel consumption varies. 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.

The parameters which influence thrust & fuel economy of engine are all of its design parameters & operating conditions -
- Compression or Pressure ratio - how much air can be compressed
- with how many fan, low pressure, high pressure compressor stages.
- Air mass flow per second
- combustor design
- Turbine inlet temperature
- # of high & low pressure stages
- Afterburner design
- Bypass ratio
- fixed/variable cycle engine


In theory there is a formula F=Ma = M(Vout-Vin) where V is air velocity at intake & exhaust.
But practically, how fast will a jet go at 100% power depends on
- airframe weight at the time
- engine design
- altitude (air density), friction force.
- airframe design producing certain amount of lift & drag due to friction & shockwaves.
- special feautures like shock compression lift.


2 same jets with different wing & fuselage design but with same # & type of engine(s) will have different performance.

Different sources give different data on Supercruise
For example F-22,
View attachment 259599

Fuel consumption is measured in units like g/KN/s or lb/lbf/hr, called SFC or Specific Fuel Consumption.

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.

F-35's F-135 engines SFC with inlet dia. 109cm at 100% power (128.1 KN.) is around 20.3 g/KN/s.
Sup.Cr. M1.2 (411.6 m/s).
So 2.6 Kg/s fuel for covering 411.6m.s or 158.3 m/Kg or 6.31 gm/m.
But to go this extra 30m/Kg-fuel Vs F-22, the SFC is increased from 17 to 20.3 g/KN/s.
F-35A Empty weight 13.3 T + 50% fuel 4.15 T + 4 AAMs 0.6 T = 18.05 tons
Airframe T/W ratio at 100% power = 128.1/9.8 /18.05 = 0.72
Fuel per ton = 2,600/18.05 = 144.04 gm/s/T.

So we see that F135 engine has more thrust but higher SFC than F119 engine,
& F-35 goes further /Kg fuel, consumes less fuel per unit distance, per ton of body BUT has lower T/W ratio and cannot supercruise.


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.
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

NOTE - Among these 3 engines F414 is smallest engine with highest SFC at 100% power.
NOTE - IDK what is the SFC of these engines at say Mach 0.7 & what is the throttle position. I think these kind of parameters are secret. Sometimes these fiigures are calculated at full IWB load, sometimes AA load + 50%-80% fuel dpending upon fuel left after reaching 35-40K feet altitude & supercruise speed.

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.


Now after knowling fuel used, distance traversed per second at Supercruising speed with 100% thrust level, if people can obtain the same data at say Mach 0.7-0.8, then merit/demerit of Supercruise can be debated.

But the R&D to increase speed, distance travelled in minimum fuel used will never stop.
Drag at Mach 1.5 is twice that of .7, check your own graph
 

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