Bell P-39D Airacobra

From The Air Combat Wiki

Contents 1 Quick Link 2 Fighter Ace Screenshots 3 Fighter Ace Ratings 4 Fighter Ace Performance 5 Historical Statistics 6 Strengths 7 Weaknesses 8 History 9 Sources 10 See Also 11 Quick Link

Quick Link

• Fighter Ace Flight Museum: WWII US / GB / SU / GE / JP / Jets and Post WWII // Planes Inventory (text list)
• Fighter Ace Plane Physics: Speeds / Accelerations / Climb Speeds / Star Ratings
• Fighter Ace Weapons: Guns / Rockets / Bombs / Torpedoes

Fighter Ace Screenshots

Fighter Ace museum screenshot by Doug@HQ	Fighter Ace museum screenshot by Doug@HQ	Fighter Ace museum screenshot by Doug@HQ	Fighter Ace museum screenshot by Doug@HQ
Fighter Ace museum screenshot by Doug@HQ	Fighter Ace museum screenshot by Doug@HQ	Fighter Ace museum screenshot by Doug@HQ

Fighter Ace Ratings

Durability: 3

Speed: 6

Maneuverability: 6

Firepower: 7

Climb Rate: 4

Ground Attack: 3

Fighter Ace Performance

Top Speeds						Climb Rates
	Sea Level	4921' 1500m	9843' 3000m	19685' 6000m	Best Speed	Best IAS	to 1000m	to 3000m	to 6000m
mph	309	334	356	354	367@ 12467'	168 mph	1:42	4:20	8:44
kph	497	537	572	569	590@ 3800m	270 kph

Historical Statistics

Service Date: March 1941

Primary Guns: 4x Browning 0.3" (7.62mm) machine guns with 1000 rpg in wings and 2x Browning M2 0.5" (12.7mm) machine guns with 200 rpg in cowl

Secondary Guns: 1x Oldsmobile M4 37mm cannon with 30 rpg in the spinner

Ordnance: 1x 250 lb (113 kg) or 500 lb (227 kg) bomb or 1x 450 lb (204 kg) drop tank

Engine(s): 1x Allison V-1700-35 in-line rated for 1,150 hp at sea level

Int Fuel Capacity: 720 lbs (327 kg)

Ext Fuel Capacity: 450 lbs (204 kg)

Maximum Speeds: 360 mpg (579 kph) at 15,000 ft (4,572 m)

Ceiling: 32,100 ft (9784 m)

Loaded Weight: 7,650 lbs (3,470 kg)

Wing Area: 213 sq ft (19.8 sq m)

Wing Loading: 35.9 lbs/sq ft (175.3 kg/sq m)

Strengths

Guns: While the secondary guns are nothing spectacular, the 37mm cannon vaults the P-39 into the position of being a tank killer.

Weaknesses

Speed: While fairly fast on the deck, especially when compared to its contemporaries, the Airacobra's performance above 15,000 feet was dismal at best.

History

When Bell's engineers set about the task of designing a fighter plane in 1936, they settled on the unorthodox idea of mounting the engine behind the cockpit. Such an arrangement allowed the cockpit to be further forward than normal, for good over-the-nose visibility, and allowed the use of extremely heavy nose-mounted armament.

The new fighter, designated the XP-39, was powered by the new Allison V-1710-17 engine fitted with a B-5 turbo-supercharger, which gave the initial prototype a top speed of 390 mph at 20,000 feet. At this point the plane was handed to the evaluation team at Langley for wind tunnel testing. The Army thus requested numerous design changes to the airframe, but most puzzling was the decision to replace the 1,150 hp, supercharged V-1710-17 with a 1,090 hp, non-supercharged V-1710-39. This modification made the plane "practically useless" above 17,000 feet, turning a promising heavy interceptor into a low-level ground support plane.

The plane was originally intended to carry a 25mm cannon in the nose, but Bell decided to use the new Oldsmobile 37mm M4 cannon instead. Unfortunately, the cannon had a tendency to jam if fired while maneuvering and it only carried 30 rounds of ammunition.

When war broke out in 1939, Bell submitted their specifications to the British Direct Purchase Commission, which resulted in an immediate order for 675 P-39s. These planes, designated Airacobra I by the RAF, were equipped with a single Hispano 20mm cannon with 60 rounds in place of the 37mm Oldsmobile cannon. Additionally, the pair of .50 caliber machine guns in the cowl and the four .30 caliber machine guns in the wing were replaced with standard British .303 machine guns.

Unfortunately, the Airacobra failed to live up to the specifications submitted by Bell. After only a single strafing mission over France on October 9, 1940, the Airacobra was grounded and was removed from RAF service three months later. Of the 675 Airacobra Is ordered by the RAF, 212 were dispatched to the Soviet Union and 179 were taken over by the USAAF. The USAAF models were designated P-400 and served alongside standard P-39Ds over Port Moresby, New Guinea in April 1942.

The lack of supercharging meant that the P-39, which was rather nimble and responsive at low level, was sluggish and unresponsive at higher altitudes. But while it couldn't serve the high-level interceptor role originally intended for the design, the P-39 was found to be a good ground-attack plane, particularly with the 37mm cannon.

Sources

Green, William; War Planes Of The Second World War: Fighters Volume Four; Macdonald & Co., London; 1961.

McDowell, Ernie; P-39 Airacobra In Action, Aircraft No. 43; Squadron/Signal Publications, Carrollton, Texas; 1980.

See Also

Bell Aircraft Corporation

Aircraft Manufacturers During World War II

Quick Link

• Fighter Ace Flight Museum: WWII US / GB / SU / GE / JP / Jets and Post WWII // Planes Inventory (text list)
• Fighter Ace Plane Physics: Speeds / Accelerations / Climb Speeds / Star Ratings
• Fighter Ace Weapons: Guns / Rockets / Bombs / Torpedoes