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Posts Tagged ‘close air support aircraft’

CAS fighter camouflage patterns proposal

Posted by Picard578 on January 1, 2016

ax1-standard Read the rest of this entry »

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Posted in proposals | Tagged: , , , , , | 10 Comments »

Close Air Support fighter proposal 3

Posted by Picard578 on December 28, 2013

Introduction

As EJ-230 turned out to be too expensive for estimated cost of aircraft, I have decided to replace it with commercial engine. Gun will also be replaced with 30 mm version of GAU-12 (henceforth GAU-32). 20% increase in size will result in gun being 2,53 m long, 0,31 m wide and 0,35 m tall. Projectile dimensions will be 30×173 mm, same as GAU-8. Rate of fire will be 4.200 rpm, with muzzle velocity of 1.000 m/s. Projectile weight will be 378 g, with total round weight of 681 g. Muzzle energy will be 189.000 J, and maximum output 13,23 MW. Gun itself will weight 211 kg. Recoil is (4.200 / 60) * 1.000 * 0,378 = 26,46 kN.

Design

AX

Length: 12,04 m (12,6 m with tail)

Wingspan: 12,97 m

Height: 3,2 m

Wing area: 26,5 m2

Empty weight: 6.500 kg

Fuel capacity: 4.900 kg

  • Rear tank: 160x110x199 cm = 16x11x19 dm = 3344 l
  • Forward tank: 220x110x110 cm = 22x11x11 dm = 2662 l
  • 1 l = 0,82 kg

Fuel fraction: 0,43

Weight: (30 mm GAU-12 round: 681 g, AGM-65: 300 kg)

With 100% fuel + 1.200×30 mm rounds: 12.217 kg

With 50% fuel + 1.200×30 mm rounds: 9.767 kg

With 100% fuel + 1.200×30 mm rounds + 4 AGM-65: 13.417 kg

With 50% fuel + 1.200×30 mm rounds + 4 AGM-65: 10.967 kg

Maximum takeoff: 13.940 kg

Wing loading:

With 100% fuel + 1.200×30 mm rounds: 442 kg/m2

With 50% fuel + 1.200×30 mm rounds: 350 kg/m2

With 100% fuel + 1.200×30 mm rounds + 4 AGM-65: 487 kg/m2

With 50% fuel + 1.200×30 mm rounds + 4 AGM-65: 395 kg/m2

Weapons:

1xGAU-32 with 1.200 rounds

6 wing hardpoints (70 mm rocket pods, 12 rockets each; AGM-65 Maverick, AGM-114 Hellfire, AIM-9, ASRAAM, IRIS-T, MICA IR)

1 centerline hardpoint (jamming pod or 500 kg fuel tank, or any of above)

Gun: GAU-32

Length: 2,53 m

Width: 0,31 m

Rate of fire: 4.200 rpm

Muzzle velocity: 1.000 m/s

Projectile: 378 g

Round: 681 g

1-second burst: 70 rounds / 13,23 MJ

Engines: ALF-502R-5 (statistics represent each engine)

Maximum thrust: 6.970 lbf (3.162 kgf, 31 kN)

SFC at maximum thrust: 0,408 lb / lbf hr

Fuel consumption at maximum thrust: 1.290 kg per hour

Cruise thrust: 2.250 lbf

SFC at cruise thrust: 0,72 lb / lbf hr

Fuel consumption at cruise thrust: 735 kg per hour

Length: 162 cm

Diameter: 102 cm

Wing loading:

488 kg/m2 at combat takeoff weight

395 kg/m2 at combat weight

Thrust-to-weight ratio:

0,47 at combat takeoff weight

0,58 at combat weight

Speed:

Maximum: 860 kph

Cruise: 490 kph

Combat radius with 10 minute combat: 1.093 km

Combat radius with 10 minute combat and 2 hour loiter: 603 km

Sensors:

radar warners

laser warners

missile warners

Countermeasures:

chaff

flares

Unit flyaway cost: 9.184.000 USD

Cost per flying hour: 1.000-1.500 USD

Sorties per day per aircraft: 3

Sorties per day per billion procurement: 324

ax

Notes

  • large tank: 140*98*122 px = 12,38*8,67*10,79 dm = 1158 l
  • small tank: 56*52*122 px = 4,95*4,6*10,79 dm = 245 l
  • wing tanks: 2 * 504*84*8 px = 2 * 44,59*7,43*0,71 dm = 2 * 235 = 470 l

This will allow extensive combat and loiter time even if one fuel tank is punctured.

ALX combat mission fuel usage will be like this:

* takeoff – 7 kg

* 10 minutes to 10.000 meters – 430 kg

* 10 minutes of combat – 430 kg

* descent – 250 kg

* landing – 4 kg

* cruise to combat area – 1.640 kg

* cruise from combat area – 1.640 kg

* unusable fuel – 10 kg

* reserve – 489 kg

Ammo capacity:

l:72 px / 63 cm, d:92 px / 80 cm

area: 450 rounds

length: 3 rounds

total: 1.350 rounds

weight: 702 kg

Wing area: 2*210*582 + 97*215 = 244.400 + 20.855 cm2 = 26,5 m2

A-10 costs 16 million USD at weight of 11.321 kg, for a cost of 1.413 USD/kg.

Naval variant will cost 11 million USD.

EDIT:

A-10 has a minimum takeoff distance of 945 meters and landing distance of 610 meters. Its takeoff weight is 21.361 kg for CAS mission, with TWR of 0,38, wing loading of 454 kg/m2. ALX has a takeoff weight of 13.417 kg, TWR of 0,47 and wing loading of 488 kg/m2.

Decrease in takeoff distance is proportional to increase in TWR. 10% increase in takeoff weight increases the takeoff run by 21%. 10% increase in landing weight increases the landing run by 10%. 10% increase in wing area (9% decrease in wing loading) decreases the takeoff speed by 5%.

Thus the ALX takeoff distance is 427 meters. (945 m > 407 > 427)

Loadouts

ax

Comparision with other fighters

AX’s weapons loadout allows it 24 attack passes; A-10 for comparision has 22 firing passes of gun ammo and 6 missiles, for total of 28 attack passes. A-10s unit flyaway cost of 16 million USD and 3 sorties per day per aircraft however mean that while A-10 can fly 186 sorties per day per billion USD, AX can fly 324 sorties per day per billion USD; a 1,74:1 sortie generation advantage; this means that AX offers 7.776 attack passes per billion procurement USD per day, compared to 5.208 for the A-10. AX is also less visible and somewhat more maneuverable owing to higher thrust-to-weight ratio and smaller size, resulting in greater survivability.

Comparing it with other fighters that are supposed to perform CAS is nowhere near being a fair play: aside from being completely incapable of performing actual CAS, fast jets are also too costly. F-16C costs 70 million USD flyaway and can fly 1,2 sorties per day, resulting in 16 sorties per day per billion USD (a 20:1 advantage for AX); F-35A costs 184 million USD flyaway and can fly 0,3 sorties per day, resulting in 1,5 sorties per day (a 216:1 advantage for AX).

F-16C has 4,7 1-second bursts from gun and can carry up to 12 bombs, for a total of 17 attack passes; F-35A has 2,6 1-second bursts and can carry up to 10 bombs, for a total of 13 attack passes. Thus per billion procurement USD, F-16C offers a total of 272 attack passes, and F-35A offers a total of 20 attack passes. From this it can easily be calculated that, for equal procurement cost, F-16C offers 13 times as many attack passes as the F-35A, A-10 offers 260 times as many attack passes as the F-35A, and AX offers 389 times as many attack passes as the F-35A.

It is also interesting to compare it to several proposed CAS fighters. First one is Pierre Sprey’s CAS fighter (America’s Defense Meltdown, pg 161). Sprey’s fighter has 30 mm cannon, 8.000 kgf of thrust, 6.350 kg empty weight, 4.500 kg of fuel (fuel fraction of 0,41), 11.300 kg combat takeoff weight; likely cost is 9 million USD. Another Fighter Mafia’s proposal, “Blitz Fighter” by James Burton (made into concept at LTV Vought Company), an airplane with empty weight of 2.300-4.500 kg, using 4-barreled 30 mm Gattling gun and a minimum of sensors; it would have cost 7,4 million USD (adjusted for inflation to 2013 USD). AX has 30 mm cannon, 6.324 kgf of thrust, 6.500 kg empty weight, 4.900 kg of fuel (fuel fraction of 0,43), 13.417 kg combat takeoff weight, and while it can carry guided AT missiles, it relies primarly on its gun and dumb weapons; it costs 9,2 million USD. It can be seen that while AX is not as radical concept as other two fighters, it offers most of the same advantages.

3D design by Riley Amos (added 16.8.2016.)

https://3dwarehouse.sketchup.com/model.html?id=6844bedc-c4b9-4d53-9f7c-5babdd827953

alx-riley-amos

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