Boeing XP-4 (Boeing Model 58)
United States Army Air Corps Experimental Biplane Fighter

Archive Photos ²

Overview ^3,4

• Boeing XP-4
• Role: Experimental Biplane Fighter
• National origin: United States of America
• Manufacturer: Boeing
• Manufacturer’s designation: Model 58
• First flight: 1927
• Primary user: United States Army Air Corps
• Number built: 1 (A.C. 25-324, c/n 737)
• Developed from: Boeing Model 15

The Boeing XP-4 was a prototype United States biplane fighter of the mid-1920s that was grounded permanently after just 4.5 hours of flight testing.

Development and Design ⁴

The Boeing Model 58 (XP-4) was the last PW-9 converted to a new experimental design through the addition of the turbo-supercharger to a Packard engine and the substitution of a new lower wing having the same dimensions as the original Boeing PW-9 upper wing in place of the regular 22 ft 5 in lower wing. There was no increase in the gap between the wings. The aerofoil section was changed from the original Göttingen 436 to a new Boeing 103A section. the armament was revised by installing one 0.30 caliber gun in each wing far enough out board to clear the propeller.

The Boeing XP-4 was 815 lb heavier than the Boeing PW-9 but had only 46 ft&su2; of additional wing area. It was severely handicapped in that it was merely an adaption of an existing aeroplane to a new configuration instead of having been designed for the best utilization of the new features. The Boeing XP-4 was delivered to Wright Field on July 27 1926, and was surveyed on May 1, 1928, since it was of no further use as a test aeroplane and was to differ from standard models for a service or advanced training squadron.

Boeing Model 58 (XP-4) Specifications ^3,4

Type

• Experimental biplane fighter

Accommodation

• Crew: 1 pilot

Power Plant

• 1 ×, Supercharged Packard 1A-1500 liquid-cooled piston engine, rated at 510 hp (380 kW)

Dimensions

• Length: 23 ft 11 in (7.29 m)
• Wingspan:
• Height: 8 ft 10 in (2.69 m)
• Wing area: 309 ft² (28.71 m²)

Weights

• Empty weight: 2,783 lb (1,264 kg)
• Max. takeoff weight: 3,650 lb (1,655 kg)

Performance

• Maximum speed: 169 mph (272.0 km/h)
• Cruise speed: 137 mph (220.5 km/h)
• Climb: 2,055 ft/min (626.4 m/min)
• Service ceiling: 22,000 ft (6,705.6 m)
• Range: 375 miles (603.5 km)

Armament

• 2 × 0.30 caliber machine guns

Identifications

• United States Army Air Corps: A.C. 25-324
• Boeing Construction Number: 737

References

1. Shupek, John. Boeing Model 58 (XP-4) 3-view drawing, The Skytamer Archive, copyright © 2017 Skytamer Images. All Rights Reserved
2. The Skytamer Archive. Boeing XP-7 Photo by the Airplane Photo Supply (APS #2438)
3. Wikipedia, the free encyclopedia. Boeing XP-4
4. Bowers, Peter M. Boeing Aircraft since 1916, Putnam Aeronautical Books, London, 1989, ISBN 0-87021-037-8, pp. 92-93