POWER PLANT: Two Pratt & Whitney R-2800-22W Double Wasp engines, rated at 2,100 hp each
PERFORMANCE: 427 mph at 19,200 ft
COMMENT: In mid 1938, the US Navy had ordered a prototype twin-engine fighter from the Grumman Company and, by middle of 1941, preliminary flight-test data for this aircraft, the XF5F-1 (Grumman G-45) was available. Although the XF5F-1 suffered a number of shortcomings, it provided a useful basis for the development of a larger twin-engine fighter. Ordered in June 1941 and designated XF7F-1 this new fighter was intended to be operated from the forthcoming 45,000 ton carriers of the USS Midway class. It was the Navy’s first twin built in production quantities, and the first carrier-based fighter to operate with a tricycle undercarriage. Although classified as a fighter the aircraft was designed to operate in a ground-support role, for which it was heavily armed. In early 1944 an order for 500 Tigercats was given and deliveries began in April 1944. Operational problems and changing requirement let to restriction in the production program. After 34 F7F-1 had been delivered production switched to 189 F7F-3s, similar to the single-seat model but with more powerful R-2800-34W engines. Including two-seated night-fighter variants , the Grumman F7F-3N Tigercat, production totaled 250 aircraft. Too late for operational service in WW II, the Tigercat served with a few Marine squadrons after the war but was soon displaced by the advent of jet-powered aircraft. (Ref. 18)
POWER PLANT: 2 x Westinghouse 19B (J30) jet engines, rated at 650 kp each
PERFORMANCE: 547 mph
COMMENTS: In 1942 John K. Northrop conceived the XP-79 as a high-speed rocket-powered flying-wing fighter aircraft. In January 1943, a contract for two prototypes with designation XP-79 was issued by the United States Army Air Forces. To test the radical design, glider prototypes were built, designated MX-324. Originally, it was planned to use a Aerojet XCALR-2000A-1 liquid-fueled rocket motor rated at 920 kp thrust supplied by monoethylanilin and red fuming nitric acid. Because of the corrosive and toxic nature of the liquids, the XP-79 was built using a welded magnesium alloy monocoque structure to protect the pilot if the aircraft was damaged in combat with a 3 mm skin thickness at the trailing edge and a 19 mm thickness at the leading edge. However, the rocket motor configuration using canted rockets to drive the turbopumps was unsatisfactory and the aircraft was subsequently fitted with two Westinghouse 19-B (J-30) turbojets instead. This led to changing the designation to XP-79B. The nickname “Flying Ram” is attributed to the unusual fighting tactic. It was planned to fly with high speed direct towards the enemy and to hit it with wingtips or fuselage. Due to its extreme stability the fighter and its pilot should survive. The XP-79B was lost during its first flight on 12 September 1945. Shortly thereafter, the second and the overall project was cancelled (Ref.: 23).
POWER PLANT: Two Rolls-Royce RB.50 Trent turboprop engines, rated at 750 hp and 570 kp thrust each
COMMENT: Experimental works with early jets proved that in the speed range of less than 450 mph the substantial reduction of fuel consumption can be obtained by fitting a reduction gearbox to the impeller of a turbojet engine driving an airscrew. In German companies such as BMW, Heinkel and Junkers were pioneers related to this new power unit and some of these were in an advanced stage of realization (Messerschmitt Me 262B-2 “Turboprop”), but the end of the war stopped all further works. Also in the UK this idea was materialized by Rolls- Royce in the form of a ‘Trent’ turboprop engine what was in fact a modified ‘Derwent’ turbojet, fitted with shaft reduction gearbox and five-bladed Rotol propellers. Two ‘Trent’ turboprops were installed in a Gloster ‘Meteor’ F. 1 turbojet fighter as a test bed. The aircraft needed little modification for the accommodation of the ‘Trent’ power plant, though the nacelles were somewhat larger, which, with the extra side area of the propellers, entailed the fitting of two small auxiliary fins towards the outboard end of the tail plane to ensure directional stability. The Gloster ‘Trent’-Meteor and became the first aircraft to take-off and fly solely on turboprop power on September, 1945. By March 1948 the development program had been completed. The results of it were embodied in highly successful Rolls-Royce ‘Clyde’ and ‘Dart’ turboprop engines (Ref.: 24).
POWER PLANT: Two Rolls-Royce Merlin 76/77 liquid-cooled engines, rated at 1,250 hp each
PERFORMANCE: 387 mph at 26,000 ft
COMMENT: The Westland Welkin was a British twin-engine heavy fighter from the Westland Aircraft Company, designed in 1940 to fight at extremely high altitudes, in the stratosphere. Westland had some expertise in twin-engine aircraft; its Whirlwind Mk.I escort fighter was in full production. The word Welkin means “the vault of heaven” or the upper atmosphere. As mentioned, first conceived in 1940, it was built from 1942–43 in response to the arrival of modified Junkers Ju 86P bombers flying reconnaissance missions that suggested the German Luftwaffe might attempt to re-open the bombing of England from high altitude. But the threat was never materialized. Consequently, Westland produced only a small number of Welkins. In total 77 aircraft were built but only few of these flew. Most of the aircraft were produced without engines. One sole aircraft was modified as Welkin II which had a lengthened nose to accommodate A.I. radar (Ref.: 23).