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Bell P-39 Airacobra Fighter (1941)

Authored By Staff Writer | Last Updated: 9/2/2013

Essentially a failed fighter design, the Bell P-39 Airacobra succeeded in the ground attack role.

The Bell P-39 Airacobra is yet another in the long line aircraft studies stemming from World War 2 in the "what-might-have been" category. The system had all the looks of a top performer, armament that could go head-to-head with any contemporary and a design philosophy that could have brought about a whole new era is aircraft engineering. Unfortunately for the aircraft, several key requirements effectively doomed the Airacobra as a subjective failure - never quite living up to expectations. Still, the system served well enough, save for its intended role of high performance fighter, and went on to become a steady performer in the low-level attack role (excelling in combat under 10,000 feet). She was sent en masse to the Soviets via Lend-Lease and shunned by the British altogether - the latter finding that the aircraft (as advertised) possessed none of the capabilities being marketed by the Bell prototype.

P-39 Quick Glance

Generally a very pleasing aircraft to look at, the P-39 design came about at a time when streamlining aircraft shapes were just coming into their own. The P-39 was a vast departure from most aircraft being conceived of at the time and featured several design elements that distinguished the type from her contemporaries. Chief among these was in the internal layout, the Allison series engine mounted in the middle of the fuselage just aft of the cockpit. Engineers ran an extended shaft from the engine through a center bearing underneath the pilots feet to the front fuselage section where the three-blade propeller and reduction gear were mounted. As a result of this engine placement, the engine had to be fed through intakes mounted along the fuselage as opposed to a conventional placement in the nose. In early P-39 forms, this meant intakes were added to the sides of the fuselage just aft of the cockpit. Other forms mounted these intakes along the wing roots and the most identifiable form saw the intake affixed to the top of the fuselage. Wings were low-mounted monoplane assemblies and the empennage featured a traditional "T-style" arrangement with a single vertical fin. The P-39 also featured a powered tricycle landing gear system, a relatively new concept in the art of aircraft design for the time.

In what turned out to be effectively an early form of the "bubble" canopy, the Airacobra featured a complex canopy design which offered up unparalleled vision over the entire design. The pilot sat in a very ergonomically-minded cockpit that featured two automotive-style "swing" doors to either side of his seat. The windows in these doors were fully retractable and done so through a car-like crank handle. Upon having to exit his aircraft in the event of damage or power loss, the pilot simply jettisoned the doors via lever and rolled out one side or the other, eventually slipping off the edges of the respective wing. If enough time was allotted, he could even make his way to the wings edge and make a controlled jump.

Cockpit design was simple and similar in scope to the P-38 Lightning and P-40 Warhawk. Control levers were dominated by the throttle lever, easily the largest of the group. Most of the main control gauges were held in a center column running from knee-to-face height and offering up easy access. The throttle and other controls were held off to the lower left in a separate assembly that included the gun controls. Space-wise, the cockpit fit the build of a standard 5'8" pilot (standard for the time at least) and offered up limited comforts for sorties that could very well last several hours. Beyond that, however, many-a-veteran would curse the system's limited conveniences on longer trips. Internally, nothing was spared in constructing a cockpit worthy of any pilots own life. The cockpit featured air-tight sections to keep deadly fumes from the nose-mounted armament out and deadly fumes from the engine from creeping in from the rear. All vital systems were held in this area of the fuselage, which itself featured rugged and sturdy construction practices that would become synonymous with Bell Aircraft for a time.

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Specifications for the
Bell P-39 Airacobra

Focus Model: Bell P-39M Airacobra
Country of Origin: United States
Manufacturer: Bell Aircraft Corporation - USA
Initial Year of Service: 1941
Production: 9,584

Crew: 1

Length: 30.15 ft (9.19 m)
Width: 33.99 ft (10.36 m)
Height: 11.84ft (3.61 m)
Weight (Empty): 5,611 lb (2,545 kg)
Weight (MTOW): 8,400 lb (3,810 kg)

Powerplant: 1 x Allison V-1710-83 water-cooled engine generating 1,200hp.

Maximum Speed: 386 mph (621kmh; 335 kts)
Maximum Range: 650 miles (1,046km)
Service Ceiling: 35,991 ft (10,970 m; 6.8 miles)
Rate-of-Climb: 3,333 feet per minute (1,016 m/min)

Hardpoints: 1
Armament Suite:
1 x 37mm Oldsmobile cannon firing through the propeller hub with 34 rounds OR 1 x 20mm Hispano-Suiza cannon.
2 x 12.7mm machine guns in the upper forward fuselage with 200 rounds each.
4 x 7.62mm machine guns in wings (2 to a wing) with 1,000 rounds each.

1 x 500lb bomb externally mounted on the centerline fuselage.

XP-39 - Prototype Model Designation sans armament.

YP-39 - Prototype Preproduction Models of which 13 were produced; improved XP-39 model.

YP-39A - Preproduction XP-39 Model fitted with an Allison V-1710 engine sans turbocharger; single high-altitude test frame conversion model.

YP-39B - Based on the XP-39; fitted with new engine sans turbocharger; single unit produced.

P-45 - Initial Production Designation offered by the US Army to signify major changes to model P-39C; later dropped in favor of P-39 designation.

P-39C - Initial Production Models; 80 examples produced; 60 P-39C models became P-39D types.

P-39D - Production Model fitted with self-sealing fuel tanks and increased heavier armament (addition of 2 x 12.7mm machine guns in upper forward fuselage); Allison V-1710-35 water-cooled engine generating 1,150hp; conversion models from P-39C series.

P-39D-1 - Lend-Lease Model with Hispano-brand 20mm cannon; improved P-39D models with self-sealing fuel tanks; 863 examples produced.

P-39D-2 - Lend-Lease Model with Allison V-1710-63 (E6) powerplant; improved P-39D-1 model series; 158 on order; 1 conversion model from P-139D-1.

XP-39E - 3 examples produced with new powerplant of Continental I-1430-1 at 2,100hp; becoming the XP-63 "Kingcobra" prototype.

P-39E - Improved P-39D-1 model; though 4,000 were on order none of this type were produced.

P-39F-1 - Based on the P-39D model but fitted with Aeroproducts-produced constant-speed propeller system.

P-39F-2 - P-39F models modified for photo reconnaissance duties; 2 converted as such.

P-39G - 1,800 were ordered though eventually becoming the K, L, M and N models in the series.

P-39H - Designation Not Used

P-39J - Modified P-39D-1 model series with new engine and auto boost feature; 25 examples produced.

P-39K - Fitted with V-1710-63 powerplant and Curtiss-produced propeller system; based on P-39F model series; 210 examples produced.

P-39L - Modified P-39K series with Curtiss brand propellerand rocket rails installation; 250 examples produced.

P-39M - Fitted with V-1710-83 powerplant capable of 1,200hp and a larger propeller system; gearing changed; 240 examples produced.

P-39N - Improved P-39M series; fitted with V-1710-85 powerplant; decreased armor protection and fuel for increased weight and performance.

P-39P - Designation Not Used

P-39Q - Improved P-39N series; 1 x 37mm cannon and 4 x 12.7mm machine guns - two held in underwing gunpods and synchronized to fire through the propeller.

Bell Model 14 - French Order Model Designation; never delivered.

Airacobra Mk I - British Delivery Models

P-400 Airacobra I - Royal Air Force Designation

TP-39F - Dual-Seat Trainer Model

RP-39Q - Limit Production Dual-Seat Trainer Model

F2L - US Navy Target Drone Designation

XFL-1 "Airabonita" - Single Example Prototype Model for evaluation by US Navy; traditional landing gear array instead of tricycle type.

A-7 - Proposed Radio-Controlled Drone

TDL - US Navy Radio-Controlled Target Drone

Australia; France; Italy; Poland; Portugal; Soviet Union; United Kingdom; United States