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Boeing XP-7 (Boeing Model 93)
United States Army Air Corps Experimental Biplane Fighter
Archive Photos 2
Historic 1928 Boeing XP-7 (A.C. 28-41, c/n 1026) photo by the Airplane Photo Supply (APS #2323)
Overview 3,4
The Boeing XP-7 (Boeing Model 93) was a prototype United States biplane fighter of the late 1920s. The XP-7 was the last airplane on the Boeing PW-9D order (A.C. 28-41) and was retained at the factory for the experimental installation of a 600 hp water-cooled Curtiss Conqueror V-1570 engine. The Curtiss V-1570 engine was an enlarged and improved version of the 435 hp Curtis D-12 engine is used in the standard PW-9. The XP-7 was delivered on September 4, 1928. The XP-8 preceded the XP-7, but his military designation was assigned later.
Development and Design 3,4
The XP-7 started life as the last Boeing Model 15 (PW-9D), United States Army air Corps serial 28-41. It was then adapted to mount the 600 hp Curtiss V-1570 Conqueror engine. The aircraft was designated by Boeing as their Model 93. The Boeing XP-7’s nose was shorter and deeper than that of the standard Boeing PW-9, and the craft was 75 pounds lighter then that of the Boeing PW-9. As noted earlier, the Boeing XP-7 had its first flight on September 4, 1928, and did well. The Boeing XP-7 demonstrated a 17 mph speed increase over the Boeing PW-9.
The Curtis V-1570 engine proved to be suitable for use in fighters, and subsequently an United States Army air Corps specification was written to cover the building of four service test Boeing P-7s. However, in recognition of the fact that the Boeing PW-9 series had about reached the limit of its growth potential and that Boeing was developing a promising new fighter, the project was canceled and the XP-7 was reconverted back to a Boeing PW-9D configuration by United States Army air Corps. With the exception of the experimental XP-9, the PW-9D/XP-7 was the last Boeing fighter to use a liquid-cooled engine.
It first flew in September 1928 and did well, with a 17 mph speed increase over the PW-9. However, despite a proposal to build an additional four P-7s, the design was at the very limits of its capabilities and somewhat outdated even by the time of its first flight. At the end of testing, the Conqueror engine was removed and the aircraft converted back into a PW-9D.
Operators 2
Boeing XP-7 (Model 93) Specifications 3,4
Type
Accommodation
Dimensions
Weights
Power Plant
Performance
Armament
References