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Boeing XP-8 - United States, 1928

Detailing the development and operational history of the Boeing XP-8 Prototype Fighter.

 Entry last updated on 4/25/2016; Authored by Staff Writer; Content ¬©

  Boeing XP-8  
Picture of Boeing XP-8
Picture of Boeing XP-8

Only a single example of the experimental Boeing XP-8 pursuit fighter was ever produced.

Following World War 1 (1914-1918), the aircraft as a military platform advanced beyond its original fabric-over-wood coverings and underpowered engines. Early forms were now being replaced by metal-skinned airframes with reinforced structures and evermore powerful engines benefitting from advancing technologies in the field. What remained however was the general biplane shape and open-air cockpit along with fixed, forward-firing machine gun armament and fixed undercarriage systems. After covering several designs for the military during and after World War 1, Boeing began work on more advanced fighter types to fulfill the new US Army Air Service "Pursuit" fighter requirements emerging and established itself as a prominent aircraft maker with their PW-9. In the middle/late 1920s, Boeing attempted to sell the renamed "US Army Air Corps" on a new pursuit type as the "XP-8" developed as a private venture offering by the company and intended to fulfill a 1925 USAAC requirement.

The Boeing XP-8 represented a "one-off" biplane fighter prototype (Boeing Model 66). It continued use of a biplane wing arrangement as well as open-air cockpit and fixed undercarriage structure. The airframe was powered by a single, front-mounted Packard engine and carried its radiator system along the lower wing root - a distinct feature in its design. The aircraft was further distinguished by its noticeably contoured nose assembly which was to aid in aerodynamic efficiency at expected speeds. Armament was consistent with aircraft of the time and made up of a combination of 1 x 0.30 caliber medium machine gun and 1 x 0.50 caliber heavy machine gun in fixed mountings for forward-firing. Power was served through a single Packard 2A-1530 series inverted "vee" engine delivering 600 horsepower allowing the XP-8 a top listed speed of 170 miles per hour while cruising was around 135 miles per hour. The aircraft displayed a service ceiling of 20,950 feet and range of 325 miles. Rate-of-climb was a useful 1,750 feet per minute. The engine drove a two-bladed propeller assembly. Dimensionally, the XP-8 showcased a length of 23 feet, 4 inches, a wingspan of 30 feet and a height of 8 feet, 4 inches. Maximum weight was listed at 3,420 lbs. The main wings were of uneven span featuring parallel struts and cabling with the pilot seated aft and under the upper wing arrangement.

The aircraft was delivered USAAC testing facilities in early 1928. Pilots noted the type's good handling characteristics thought he test vehicle could not attained required speeds for an Army fighter. Engine problems soon developed where engine oil and water would leak into the bottom of the powerplant and foul sparkplugs. The issue was never resolved and, despite evaluation into June of 1929, the aircraft was not accepted for Army service. The prototype was then scrapped and lost to history though Boeing utilized some qualities of the design to sell the US Navy, Japan and Brazil on its F2B model - 33 built in all.

Boeing XP-8 Specifications

Service Year: 1928
Type: Prototype Fighter
National Origin: United States
Manufacturer(s): Boeing - USA
Total Production: 1

Structural (Crew, Dimensions, Weights)

Operating Crew (Typical): 1
Overall Length: 23.43 feet (7.14 meters)
Overall Width: 30.09 feet (9.17 meters)
Overall Height: 8.99 feet (2.74 meters)

Weight (Empty): 2,392 lb (1,085 kg)
Weight (MTOW): 3,417 lb (1,550 kg)

Power / Performance (Engine Type, Top Speed)

Engine: 1 x Packard 2A-1500 liquid-cooled piston engine developing 600 horsepower.

Maximum Speed: 153 knots (176 mph; 283 kph)
Maximum Range: 283 nautical miles (326 miles; 525 km)
Service Ceiling: 20,965 feet (6,390 meters; 3.97 miles)
Rate-of-Climb: 1,750 feet-per-minute (533 m/min)

Armament / Mission Payload

1 x 0.30 caliber machine gun
1 x 0.50 caliber machine gun

Global Operators (Customers, Users)

United States

Model Variants

XP-8 - Base prototype designation

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