Bell XFL Airabonita

https://en.wikipedia.org/wiki/Bell_XFL_Airabonita

The Bell XFL Airabonita was an experimental carrier-based interceptor aircraft
developed for the United States Navy by Bell Aircraft Corporation of Buffalo,
New York. It was similar to and a parallel development of the U.S. Army Air
Corps’ 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.

The XFL-1 (Bell Model 5) was powered by a single 1,150 hp (858 kW) Allison
XV-1710-6 twelve cylinder, two bank Vee, liquid-cooled engine installed
amidships behind the pilot and driving a three bladed Curtiss Electric 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 firing 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 utilized 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.


Role
carrier-based interceptor aircraft

National origin
United States

Manufacturer
Bell Aircraft

First flight
13 May 1940

Status
Canceled

Primary user
United States Navy

Number built
1

Unit cost

$125,000


Developed from
Bell P-39 Airacobra

In January 1938, the U.S. Navy issued a specification for a light carrier-based
fighter to replace the obsolete biplanes then in use. On 11 April 1938, Bell,
Brewster, Curtiss, Grumman, and Vought-Sikorksy submitted proposals but only
three received contracts. Two of them were awarded contracts for one prototype
each on 30 June 1938; these were for the Grumman XF5F-1 Skyrocket and the Vought
XF4U-1 Corsair. The third contract, which was signed on 8 November, went to Bell
Aircraft for one XFL-1 Airabonita. All three aircraft made their first flight in
1940: the XF5F-1 on 1 April, the XFL-1 on 13 May, and the XF4U-1 on 29 May.

Subsequent tests were prolonged because of difficulties with the Allison engine
and problems with the balance of the aircraft. Official evaluation began in July
1940 but the XFL-1 failed to be certified for carrier operations because of main
landing gear problems. The prototype was returned to Bell for modifications in
December 1940 and returned to the Navy on 27 February 1941 at Naval Air Station
Anacostia, District of Columbia. Based on the test results, the Navy decided not
to order production of the aircraft.

In February 1942, the XFL-1 was transferred to the Aircraft Armament Unit at
Naval Air Station Patuxent River, Maryland. It was later grounded, used for
armament tests, and later destroyed. For many years its remains were visible at
the dump at NAS Patuxent River.

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.

Lastly, the Airabonita had to compete against the faster though not "light"
Vought F4U Corsair, which in the initial F4U-1 version was capable of 390 mph at
24,000 ft.

Specifications (XFL-1 Airabonita)

General characteristics
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)

Performance
Maximum speed: 336 mph (541 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)

Armament

Guns:
2 × 0.30 cal (7.62 mm) machine guns
1 × 0.50 cal (12.7 mm) machine gun or 37 mm cannon



*

Miloch wrote in
:

https://en.wikipedia.org/wiki/Bell_XFL_Airabonita


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."



The story I heard from veterans was that
liquid cooled engines were complicated to work
on and prone to damage even when not in combat.
The Japanese Hien "Tony" was an excellant design
but largely kept out of combat due the complexity
of repairs. Air cooled engines could have entire
cylinders shot off and still make it back to base,
whereas one hit in the cooling system would down
a liquid cooled plane. That was not overly critical
in the ETO but would mean death in huge expanses of
the Pacific.