Defense Issues

Military and general security

  • Follow Defense Issues on WordPress.com
  • Enter your email address to follow this blog and receive notifications of new posts by email.

    Join 262 other followers

  • December 2013
    M T W T F S S
     1
    2345678
    9101112131415
    16171819202122
    23242526272829
    3031  
  • Categories

Archive for December 7th, 2013

Close Air Support fighter proposal revised

Posted by picard578 on December 7, 2013

Introduction

 

Due to the thrust shortfall of the AX, and the range shortfall of the ALX, I have decided (after consultation with vstol jockey) to design a new, single-engined CAS fighter designed around the EJ-230. Another problem with previous AX design was its lack of close-coupled canards, caused by position of its turbofan engines.

 

Design

 

CAS fighter needs to be stealthy, very maneuverable at low speed, and able to quickly attack the opponent. This means small size, low wing loading, straight wing and high thrust-to-weight ratio. Close-coupled canards are also advantageous for maneuverability, takeoff/landing performance and safety. Cannon should be of revolver design, with relatively large calibre and high rate of fire. Another requirement is good endurance, achieved by high fuel fraction. Engine will be single EJ230 in order to reduce profile to minimum and allow good acceleration.

 

??????????????????

 

Length: 11,24 m

Wing span: 10,61 m

Height: 2,22 m

Wing area: 26,88 m2

 

Empty weight: 3.900 kg

Operational empty weight: 4.100 kg

Armed empty weight: 6.377 kg (6 AGM-65); 10.577 kg (6*1.000 kg bombs)

Fuel capacity: 2.865 kg

Maximum takeoff weight: 13.422 kg (theoretically 17.500 kg)

Combat takeoff weight: 9.442 kg (6 AGM-65); 13.422 kg (6*1.000 kg bombs)

Combat weight: 8.010 kg (6 AGM-65); 11.990 kg (6*1.000 bombs)

Fuel fraction: 0,42

 

Engine: EJ230

Dry thrust: 72 kN (7.342 kgf)

Fuel consumption (cruise): 700 kg/h

Fuel consumption (maximum dry): 5.702 kg/h

Installed weight: 1.000 kg

Length: 400 cm

Inlet diameter: 74 cm

Thrust-to-weight: 11:1

http://de.academic.ru/dic.nsf/dewiki/414180#EJ230

 

Gun: GIAT 30

Weight: 120 kg

Bullet weight: 530 g

Projectile weight: 275 g (HE)

Caliber: 30 mm

Rate of fire: 2.500 rpm / 42 rps

Time to full rate of fire: 0,05 s

Muzzle velocity: 1.025 m/s

Muzzle energy: 144 kJ

Overall energy: 6 MW

 

Weapons:

1 GIAT 30 with 900 rounds

6 wing hardpoints (rocket pods, AT missiles (AGM-65, 300 kg), bombs, ECM pods)

1 centerline hardpoint (ECM pod, 800 kg fuel tank)

 

Wing loading:

351 kg/m2 at combat takeoff weight

298 kg/m2 at combat weight

 

Thrust-to-weight ratio:

0,78 at combat takeoff weight

0,92 at combat weight

 

Flight time on internal fuel: 4,09 hours

Flight time with centerline fuel tank: 5,24 hours

 

Speed:

Maximum: 900 kph

Cruise: 550 kph

 

Combat radius: 1.100 km

Combat radius with centerline fuel tank: 1.441 km

Combat radius with 1 hour loiter: 825 km

Combat radius with 2 hour loiter: 550 km

Combat radius with 3 hour loiter: 275 km

Combat radius with 4 hour loiter and centerline fuel tank: 300 km

 

Takeoff distance: 700 m

Landing distance: 900 m

 

Unit flyaway cost: 5,5 million USD

Operating cost per hour: 5.500 USD

Sorties per day per aircraft: 3

 

Notes

 

Fuel tanks:

1: 147*109*91 = 1.458.093 cm3

2: 163*112*91 = 1.661.296 cm3

3: 4*139*49*8 = 108.976 cm3

4: 2*139*49*8 = 217.952 cm3

5: 2*149*49*8 = 116.816 cm3

TOTAL: 3.563.133 cm3

0,804 kg/l

 

Naval variant will weight 4.200 kg empty and cost 5,9 million USD.

 

Comparision with other fighters

 

Here, I will compare ALX with A-10, Su-25, Pierre Sprey’s proposed CAS fighter (America’s Defense Meltdown, pg 161) and the “Blitz Fighter” by James Burton.

 

ALX has an empty weight of 3.900 kg with 2.865 kg fuel (fuel fraction 0,42). With it, it has combat radius of 1.100 km, 550 km with 2 hour loiter or 235 km with 1,88 hour loter and 10 minute combat. Armament offers 21 gun burst plus 6 missile hardpoints, for a total of 27 attack passes. Thrust-to-weight ratio at anti-tank combat takeoff weight is 0,78, and wing loading 351 kg/m2. Unit flyaway cost of 5,5 million USD allows 182 aircraft for 1 billion USD, providing 546 sorties and 14.742 attack passes per day.

 

A-10 is current US close air support aircraft, and only US fighter ever that was designed specifically for close air support. It has a combat radius of 460 km at 1,88 hour loiter and 10 minute combat. Armament includes single 30 mm GAU-8 with 1.174 rounds and 11 hardpoints, of which at least 8 can be used for carrying weapons. GAU-8 fires 52 rounds in a first second of firing, thus resulting in a total of 22 gun bursts; along with 8 missiles, A-10 can have up to 30 attack passes. Thrust-to-weight ratio at anti-tank combat takeoff weight is 0,38, and wing loading 406 kg/m2. At unit flyaway cost of 16 million USD, 1 billion USD budget gives 62 aircraft, allowing a maximum of 186 sorties and 5.580 attack passes per day.

 

Su-25 is a Russian A-10 equivalent. It has a combat radius of 400 km at unknown loter time. Armament includes single twin-barrel 30 mm GSh-30-2 with 250 rounds and 11 hardpoints, of which at least 8 can be used for carrying weapons (same as A-10). GSh-30-2 fires 50 rounds per second, thus resulting in a total of 5 gun bursts; with 8 missiles, Su-25 can have up to 13 attack passes. At unit flyaway cost of 14 million USD, 1 billion USD gives 71 aircraft; assuming same sortie rate as the A-10, it allows a maximum of 213 sorties and 2.769 attack passes per day.

 

Pierre Sprey’s fighter has an empty weight of 6.350 kg, with 4.536 kg of fuel. Combat takeoff weight is below 11.340 kg. 8.165 kgf of thrust give it a thrust-to-weight ratio midway through the mission of 0,9. Cost is conservatively estimated as 15 million USD, but realistic cost is 9 million USD, allowing 111 aircraft and 333 sorties for 1 billion USD.

 

James Burton’s Blitzfighter has an empty weight of 2.530 kg with 770 kg of fuel, for a fuel fraction of 23%. With 238 kg of payload, combat takeoff weight is 3.538 kg, and combat weight 3.153 kg. It has 15,7 m2 of wing, and engine producing 2.291 kgf of thrust. Wing loading is 225 kg/m2 at combat takeoff weight and 201 kg/m2 at combat weight, with thrust-to-weight ratio of 0,65 at takeoff and 0,78 at combat weight. Only weapon is GAU-13 cannon with 350 rounds; this allows a total of 12 gun bursts. Combat radius is 240 km with no loiter. Cost is 2 million USD in 1979 USD, or 6,78 million USD in 2013 USD. More realistic cost of 3,57 million USD would allow 280 aircraft and 840 sorties and 10.080 attack passes per day for 1 billion USD.

Posted in Uncategorized | Tagged: | 17 Comments »

 
%d bloggers like this: