Bell XFL Airabonita
|First flight||13 May 1940|
|Primary user||United States Navy|
|Developed from||Bell P-39 Airacobra|
The Bell XFL Airabonita was a United States experimental shipboard interceptor aircraft developed for the United States Navy by Bell Aircraft. It was similar to and a parallel development of the land-based P-39 Airacobra, differing mainly in the use of a tailwheel undercarriage in place of the P-39's tricycle gear. Only one prototype was manufactured.
Design and development
The XFL-1 (Bell Model 5) was powered by a single Allison XV-1710-6 piston engine installed amidships behind the pilot and driving a three bladed Curtiss propeller in the nose through a 10.38 ft (3.16 m) extension shaft. The aircraft had provisions for a single 37 mm (1.46 in) Oldsmobile T9 cannon which could be replaced by a .50 in (12.7 mm) Browning M2/AN machine gun through the propeller shaft and two .30 in (7.62 mm) machine guns in the fuselage nose. It first flew on 13 May 1940.
Although based on the P-39, the XFL-1 utilised a conventional tail-wheel undercarriage and the coolant radiators were housed externally in fairings under the wings instead of within the wing center section. The Allison engine was the first of its type to be tried out by the Navy and lacked the turbosupercharger fitted to the XP-39.[N 1]
Delivery of the prototype to the U.S. Navy was delayed due to difficulties with the Allison engine until February 1941 and it was not accepted as navy property until March. During tests, the aircraft was plagued with engine and landing gear problems and was returned to Bell for modifications in December 1941, but before the modifications were completed, the U.S. Navy decided that the XFL-1 was not suitable for further development.
As a possible further reason for the rejection it is often stated that the Navy's position during that era was that all its aircraft should use air-cooled engines (while the Allison was liquid-cooled). This appears unfounded speculation. The U.S. Navy "would consider a liquid-cooled engine installation provided a material increase in performance over air-cooled engine can be shown."
In addition, the Allison engine had only a single-speed supercharger, consequently, its altitude performance was much inferior to other naval fighters of the period such as the Grumman F4F Wildcat. [N 2]
Specifications (XFL-1 Airabonita)
Data from
- Crew: One
- Length: 29 ft 9 in (9.07 m)
- Wingspan: 35 ft 0 in (10.67 m)
- Height: 12 ft 9 in (3.89 m)
- Wing area: 232 ft² (21.6 m²)
- Empty weight: 5,161 lb (2,341 kg)
- Loaded weight: 6,651 lb (3,017 kg)
- Max. takeoff weight: 7,212 lb (3,271 kg)
- Powerplant: 1 × Allison XV-1710-6 V-12 piston engine, 1,150 hp (858 kW)
- Maximum speed: 307 mph (464 km/h)
- Range: 1,072 mi (1,725 km)
- Service ceiling: 30,900 ft (9,421 m)
- Rate of climb: 2,630 ft/min (13.4 m/s)
- Wing loading: 29 lb/ft² (140 kg/m²)
- Power/mass: 0.17 hp/lb (280 W/kg)
- 2 × 0.30 cal (7.62 mm) machine guns
- 1 × 0.50 cal (12.7 mm) machine gun or 37 mm cannon
- Related development
- Note: Navy engines were distinguished by the use of an even dash number while those for the Army used odd ones.
- The U.S. Army Air Corp's P-39 and Curtiss P-40, which used the same engine, had the same difficulty; the Lockheed P-38 Lightning used the same engines but incorporated exhaust-driven superchargers to achieve good altitude performance.
- Dorr and Scutts 2000, p. 19.
- Bowers 1979, pp. 26–30.
- Thomason 2008, p. 1.
- Thomason 2008, p. 49.
- Dorr and Scutts 2000, p. 20.
- Thomason 2008, p. 52.
- Bowers, Peter M. "Airborne Cobra Pt.II". Airpower, Vol. 9, No. 1, January 1979.
- Dorr, Robert F. and Jerry C. Scutts. Bell P-39 Airacobra. Ramsbury, Marlborough, Wiltshire, UK: The Crowood Press Ltd., 2000. ISBN 1-86126-348-1.
- Green, William. "Bell XFL-1 Airabonita". War Planes of the Second World War, Volume Four: Fighters. London: Macdonald & Co. (Publishers) Ltd., 1961 (6th impression 1969), pp. 13–14. ISBN 0-356-01448-7.
- Green, William and Gordon Swanborough. "Bell XFL-1 Airabonita". WW2 Aircraft Fact Files: US Navy and Marine Corps Fighters. London: Macdonald and Jane's Publishers Ltd., 1976, p. 3. ISBN 0-356-08222-9.
- Kinzey, Bert. "XFL-1 Airabonita". P-39 Airacobra - in detail. Carrollton, Texas: Squadron/Signal Publications Inc., 1999, p. 8. ISBN 978-1-88897-416-4.
- Thomason, Tommy. Bell XFL-1 Airabonita (Naval Fighters Number Eighty-One). Simi Valley, California: Ginter Books, 2008. ISBN 0-942612-81-7.
- Tomalik, Jacek. Bell P-6 Kingcobra, XFL-1 Airabonita, P-39 Airacobra (Monografie Lotnicze 59) (in Polish). Gdansk, Poland: AJ-Press, 2001. ISBN 83-7237-034-6.
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