The Curtiss YP-37 was a precursor to the P-40 that became the US's main fighter in the early years of World War II. The 'long-nosed' P-37 was a Curtiss attempt in the late 1930s to couple the P-36 Mohawk design with the 992kW Allison V-1710-21 inline engine. Essentially, the P-37 was a development of the P-36 (Hawk 75) fitted with an Allison engine equipped with an exhaust-driven turbo-supercharger in an effort to improve performance at higher altitudes.
Because the supercharger was placed behind the engine, the pilot's cockpit had to be re-located further aft in order to maintain the airplane's balance. The result had a unacceptably detrimental effect on the pilot's view from the cockpit. The pursuit ship had some promise, but with a few serious drawbacks, including poor visibility from its far-aft enclosed cockpit.
The sole XP-37, ordered in 1937 with a supercharged V-1710-11 powerplant, was nothing more than a P-36 airframe with the engine change. It was quickly apparent that the pilot not only could not see well in flight but also on the ground he could scarcely see.
It was hoped that some improvement would be offered by the 13 service-test YP-37 airframes which were 0.56m longer and had the V-1710-21 engine. Although the new engine/supercharger combination was quite troublesome in the XP-37, the Army was nevertheless impressed by the potential of the design, and on December 11, 1937 they ordered 13 service test YP-37s.
The YP-37 aircraft went through rigorous tests at Wright Field, Ohio, including gunnery tests, but the visibility problem was not resolved and the YP-37s were not as stable as Army pilots wanted. Serious consideration was given to further development, but at the time Curtiss was also about to come forth with the P-40 which offered an inline powerplant without the drawbacks. Though they contributed to knowledge gained by fighter designers and tacticians, the YP-37s never reached operational service as other types appeared with greater promise.
At one point, it was equipped with three superchargers: two mechanical and one turbo. They found that the hubs for the Turbo, extended too much from the fuselage. That created too much drag and top speed was only 290mph with the Turbo. Originally the P-37, P-38 and P-39 were to be turbo supercharged. The space required for the turbo and intercooler resulted in the aft cockpit placement configuration of the P-37 The XP-37 differed slightly from the YP-37, but both were turbo supercharged.
In addition, the turbo-supercharger proved to be unreliable. Those were the principal reasons why the fighter was not accepted. The P-40, which had a less cumbersome gear-driven supercharger and a better pilot's view, was accepted for production instead.
As world conflict loomed, multi-role missions were now being foreseen for aircraft once intended solely to chase other aircraft, and machines capable of a range of combat functions would increasingly become known not as pursuit ships but as fighters.
The XP-37 was retired to an Army mechanics' school in August 1941 with a total of only 152 hours of flying time.
|Take-off weight||3255 kg||7176 lb|
|Empty weight||2596 kg||5723 lb|
|Wingspan||11.38 m||37 ft 4 in|
|Length||10 m||33 ft 10 in|
|Height||2.90 m||10 ft 6 in|
|Wing area||21.92 m2||235.94 sq ft|
|Max. speed||547 km/h||340 mph|
|Ceiling||10360 m||34000 ft|
|Range||1400 km||870 miles|
|ARMAMENT||1 x 7.62mm + 1 x 12.7mm machine-guns|
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