Talk:Lockheed XP-49
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[edit] From P-38 Lightning
I cut the following out of the P-38 article. It needs incorporation here:
Lockheed also built two sister designs to the P-38: the XP-49 and the XP-58 Chain Lightning.
In spring 1939, the Air Corps issued a request for an advanced twin-engine interceptor, to be derived from an existing type and fitted with advanced high-performance engines. Lockheed responded to the request with the Model 222, based on the L22 except for a pressurized cabin, to be powered by 24-cylinder inline Pratt & Whitney X-1800-SA2-G engines, then in development and expected to provide over 2,000 hp (1,500 kW). The Model 222 was to be armed with four 12.7 mm and two 20 mm guns, and a P-38G was modified to test this armament fit.
The Model 222 won the competition, the Air Corps ordering a single prototype as the XP-49 in October 1939. Lockheed proposed production P-49s be fitted with turbocharged Wright R-2160 Tornado radials with 2,300 hp (1,720 kW) each, which would give the P-49 an estimated performance of 800 km/h (500 mi/h) at altitude.
Work on the XP-49 went slowly as Lockheed was caught up in the prewar US military buildup. As development work plodded along, both the Air Corps and Lockheed began to have doubts for various reasons about the powerful engines to be fitted to the aircraft, and so the design was changed to incorporate two Continental XIV-1430-9/11 12-cylinder inverted-vee engines with 1,540 hp (1,150 kW) each for takeoff.
Engine availability further delayed development of the aircraft, and the XP-49 didn't take to the air until April 1942. The XP-49 looked much like a P-38, except for increased length and longer nacelles; the two aircraft shared about two-thirds of their parts. The aircraft was evaluated into the summer of 1943, but the Continental engines were troublesome.
Some sources claim the XP-49 had few if any performance advantages over existing P-38 production, others cite a test pilot as saying it "fly rings around the Lightning," but whatever the case, the USAAF abandoned all plans to put the XP-49 into production. The single prototype was used for occasional tests, including being dropped from a crane to simulate hard landings, and was finally scrapped in 1946.
The XP-58 actually started life in the spring of 1940 as an advanced escort fighter version of the P-38, with the development at the request of the USAAF. Single-seat and two-seat versions were considered, with the two-seat version fitted with addition turret-mounted armament.
The single-seat version was quickly abandoned, and the two-seat version went through a number of radical design changes, particularly with regards to engine fit. With the outbreak of the Pacific War in December 1941, the project was more or less put on the "back burner," with most of the staff moved to higher-priority projects.
The USAAF then began to flip-flop on their requirements, redefining the XP-58 as a ground attack aircraft, then a bomber, then an interceptor, with a bewildering variety of equipment fits considered. The single XP-58 prototype finally flew on 6 June 1944.
The XP-58 was a much more radical departure from the original P-38 design than the XP-49. While the XP-58 had the general Lightning configuration, nobody could have mistaken it for a Lightning. It was a monster, more on the scale of the Northrop P-61 Black Widow night fighter, and powered by two 24 cylinder Allison V-3420-11 inline engines with 2,100 hp (1,570 kW) each.
The XP-58 was to mount four 37 mm fixed forward-firing cannon and two remote-control barbettes, each with two 12.7 mm machine guns, mounted at the rear of the crew nacelle. An alternate forward armament of two 12.7 mm machine guns and a 75 mm cannon, for breaking up bomber formations, was also considered, but in reality no armament was ever fitted.
By the time the prototype flew, the USAAF had completely lost interest in the project, leading to a short and undistinquished flight test program. A second prototype was never completed, and the one flying example was scrapped after the war.
