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Grumman G-34 / XF5F-1 Skyrocket / XP-50

 

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G-34 / XF5F-1 Skyrocket

 

Ordered as a prototype on 30 June 1938 by the US Navy Bureau of Aeronautics, the XF5F-1 was of radical concept in that it was intended as a twin-engined shipboard fighter, and this at a time when the first single-engined shipboard fighter monoplanes were only just commencing flight test. Conceived as the G-34 Skyrocket, the XF5F-1 was flown on 1 April 1940, and, in its initial form, had a singular appearance resulting from an abbreviated forward fuselage, the wing leading edge extending ahead of the fighter's nose. Powered by two 1,200 hp Wright XR-1820-40/42 radials and having provision for two 23-mm Madsen cannon, the XF5F-1 underwent some redesign as a result of testing, the engine nacelles being lengthened, the fuselage nose being extended, etc. Flight testing of the XF5F-1 provided information utilised in the development of the more advanced XF7F-1 (G-51).


Despite the economic circumstances and America's declining influence in world affairs, Congress loosened its purse strings wide enough to allow the Navy to modernise its naval air arm. As a result, the Navy became involved in three new fighter projects - the Grumman XF5F-1 and similar USAAF XP-50, the Bell XF1-1 and the Vought XF4U-1. The long term intention was to bolster the Navy's sagging carrier forces whose squadrons flew the Grumman F3F-2 biplane fighter harking back to the mid-1930s

 

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G-34 / XF5F-1 Skyrocket
 
The introduction of speedier and more heavily armed low wing fighters emerging from Europe such as Britain's Supermarine Spitfire and Germany's Messerschmitt Bf 109 capable of speeds well over 300mph (483km/h) made the Navy's task ever more urgent. In addition, the changing military environment, along with the gathering storm clouds of impending war in Europe, spurred Navy officials to investigate new concepts in aircraft design   the XF5F 1 Skyrocket. Ordered by the navy as the XF5F-1 [1442] on 30 June 1938, it was flown on 1 April 1940 piloted by R A "Bud" Gillies.
 
Not only was the G-34 an advanced concept, in its original form it was a most unusual-looking aircraft, with the leading edge of its low-set monoplane wing forward of the fuselage nose. The tail unit had twin endplate fins and rudders, and the landing gear was of the retractable tailwheel type, with the main units retracting aft into the wing-mounted engine nacelles. The engines were two Wright R-1820 Cyclones, each with a three-bladed propeller, these being geared to counter-rotate to offset the effects of propeller torque.
 
Flight test data early on in the Grumman G 34 (factory designation) revealed the Skyrocket was capable of outstripping in speed practically all other fighters then in both air services. At 16,000ft (4,877m), it achieved a top speed of 380mph and had an initial climb of 4,000ft (1,200m) per minute. Armament consisted of four 0.50 calibre Brownings.
 
Grum-F5F-01
 
In the summer of 1941, XF5F-1 was tested in competition against F2A, F4F, XF4U, XFL-1, P-39, P-40, and British Hurricane and Spitfire. After familiarization flights in each aircraft, pilots flew a specified series of maneuvers, then submitted pilot reports on each. LtCdr John Crommelin had this to say about F5F:
"I remember testing against XF4U in a climb to 10,000'... I pulled away from the Corsair so fast I thought he was having engine trouble. F5F was a carrier pilot's dream ... opposite- rotating props eliminated all torque, and you had no engine in front to look around to see the LSO (Landing Signal Officer). Analysis of all data favored F5F, and Spitfire came in a distant second." Availability of spare parts at the time and other particulars cancelled F5F, and the Navy chose F4F instead for production.

 

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Despite the glowing performance figures the Skyrocket's future was suddenly scrapped by the Navy, mainly for a combination of technical reasons and doubts over what some considered to be radical features. The Navy's enthusiasm blunted by several problems in the Skyrocket testing programme such as engine cooling, instability in certain flight conditions and the wing's odd position obstructing the view forward during carrier landings. Modified under a Dick Hutton design, the F5F received inward-rotating props, a new canopy and longer nose in 1941.
 
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Grumman XF5F-1 long-nose
 
After completing 211 test flights, the XF5F 1 (BuNo 1442) was cancelled in early 1941. It did, however, lead to the XP-50 for the Army Air Corps.
 
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Grumman XF5F-1 Third revision [1442]

 

 

 

XF5F-1
Engine: 2 x Wright XR-1840-40/42 Cyclone, 1,200-hp.
Wingspan: 12.80 m / 42 ft 0 in
Length: 8.75 m / 28 ft 8 in
Height: 3.45 m / 11 ft 4 in
Wing area: 28.19 sq.m / 303.43 sq ft
Max take-off weight: 4599 kg / 10139 lb
Empty weight: 3677 kg / 8106 lb
Loaded weight, 10,138 lb (4599 kg).
Max. speed: 616 km/h / 383 mph at sea level, 380 mph (611 km/h) at 16,500 ft (5030 m)
Range: 1930 km / 1199 miles at 210 mph (338 km/h)
Max climb, 4,00ceiling: 33,000' ft
Seats: 1

 

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Grumman XF5F Skyrocket

 

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Grumman XP-50

 

 

Despite the glowing performance figures the Skyrocket's future was suddenly scrapped by the Navy, mainly for a combination of technical reasons and doubts over what some considered to be radical features. The Navy's enthusiasm blunted by several problems in the Skyrocket testing programme such as engine cooling, instability in certain flight conditions and the wing's odd position obstructing the view forward during carrier landings.  Modified under a Dick Hutton design, the F5F received inward-rotating props, a new canopy and longer nose in 1941.

 

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Grumman XF5F-1 long-nose

 

After completing 211 test flights, the XF5F 1 (BuNo 1442) was cancelled in early 1941. It did, however, lead to the XP-50 for the Army Air Corps.

 

 Grum-F5F-03.jpg 26-7

Grumman XF5F-1 Third revision [1442]

 


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