Overview

• Boeing Model 15
• Role: Pursuit fighter (PW-9); Carrier Fighter (FB series)
• Manufacturer: Boeing
• Introduced: 1923
• Primary users: U.S. Army Air Service, U.S Navy, U.S. Marine Corps
• Number built: 155
• Developed from: Fokker D.VII

The Boeing Model 15 was a United States open-cockpit biplane fighter aircraft of the 1920s, manufactured by the Boeing company. The Model 15 saw service with the United States Army Air Service (as the PW-9 series) and with the United States Navy as a carrier-based fighter (as the FB series).

Design and Development

The design of the Model 15 was based on studies of the Fokker D.VII, 142 of which were brought back to the United States for evaluation as part of the Armistice Agreement ending World War I. Many of the feature were similar. The Model 15 had a fuselage of welded steel tubing braced with piano wire, while the tapered single bay wings were fabric on a wooden frame, with spruce and mahogany wing spars and 3-ply wood ribs. Wing struts were changed from the normal wood used in Boeing designs to streamlined steel tubes. The landing gear had a straight axle streamlined into a small 16 inch wing.

The original engine was a 300-hp Wright-Hispano, but when the 435-hp liquid-cooled Curtiss D-12 became available the aircraft was redesigned, moving the radiator from the nose to a "tunnel" under the engine. Along with some other minor design changes to the wings, the design was finalized on 10 January 1922.

The Army expressed interest in the new design, and agreed to provide armament, powerplants, and test the aircraft, while leaving Boeing the rights to the aircraft and design. The contract was signed on 4 April 1923 and the first prototype, designated XPW-9 for "Experimental Pursuit, Water-cooled engine", flew on 2 June 1923. The XPW-9 competed with the Curtiss Model 33 for contracts for a pursuit aircraft to replace the Thomas-Morse MB-3A in the U.S. Army Air Service.

Ultimately both models were accepted, with the Curtiss aircraft designated PW-8 and the Model 15 designated PW-9. The Air Service preferred the PW-9, which outperformed the PW-8 in all performance aspects except speed, and was built on a more rugged and easier to maintain design, ordering 113 aircraft (only 25 PW-8’s were procured). A naval version was also developed, designated FB, and 42 aircraft produced.

Operational History

Deliveries of the first 25 PW-9s began on 30 October 1925. Boeing delivered a total of 113 PW-9s of all variants including prototypes to the United States Army Air Corps between 1925 and February 1931. Virtually all PW-9s served with overseas units, in Hawaii with the 5th Composite Group at Luke Field and later the 18th Pursuit Group at Wheeler Field, and in the Philippines with the 4th Composite Group at Clark Field, Luzon. PW-9s equipped the 3^rd, 6^th, and 19^th Pursuit Squadrons between 1925 and 1931.

The FB-1, of which the Navy ordered 16 but received only 10 between 1 and 22 December 1924, was not modified for naval operations (for instance, no arresting hook), and was assigned to Marine Corps squadrons VF-1M, VF-2M, and VF-3M, being deployed to China in support of the Marine Expeditionary Force. Two additional planes, designated FB-2, were altered to operate on USS Langley (CV-1) with the addition of arresting gear and a straight-across axle for the landing gear. These went into service with VF-2 in December 1925. Generally satisfactory results led to an order for 27 FB-5’s, which became the Navy’s first fighters intended specifically for carrier operation. They were upgraded to 525-hp Packard 2A-1500 engines, and sported a row of hooks on the bottom of the axle, used to guide the plane via cables on the deck. The FB-5 first flew October 7, 1926 and was delivered to the Navy beginning in the following January, carried on barges in Puget Sound from Boeing’s factory to the Langley anchored in Seattle’s harbor. Hoisted aboard, their first official flights were from the carrier’s deck.

Variants

• XPW-9
  Three prototypes built for Air Service evaluation. First aircraft scrapped at McCook Field on 21 February, 1925, second static tested in October 1928 and the third was still flying in December 1928.
• PW-9
  30 produced 1925-26, first production variant, D-12 engine.
• PW-9A
  24 produced 1926-27, D-12C engine.
• PW-9B
  One modified PW-9A, delivered as PW-9B in 1927.
• PW-9C
  40 produced 1927-28, D-12D engine.
• PW-9D
  16 produced 1928-34, final production variant.
• XP-4
  Designation of one PW-9 (s/n 25-324) re-engined with 510 hp Packard 1A-1500 engine. Boeing Model 58.
• AT-3
  Designation of one PW-9A (s/n 26-374) converted to single-seat trainer with Wright-Hispano engine.
• FB-1
  10 built, initial Navy delivery, shore-based only.
• FB-2
  Two FB-1s modified for carrier operation, Packard 1A engine. Boeing designation Model 53.
• FB-3
  Three built to evaluate Packard 1A engine, float-plane model. Boeing Model 55.
• FB-4
  One built, experimental model with a 450 hp Wright P-1 radial engine. Boeing designation Model 54.
• FB-5
  27 built, production version. Powered by 520 hp (388 kW) Packard 2A-1500 engine. Boeing Model 67.
• FB-6
  One built, experimental model with a 450 hp Pratt & Whitney R-1340-B Wasp engine.
• FB-7
  Proposed version, powered by a Pratt & Whitney Wasp engine, not built.

Operators

• United States: United States Army Air Corps, United States Navy, United States Marine Corps

Boeing FB-5 Specifications

• Boeing Model Number 67
• Span: 32 ft
• Length: 23 ft 9 in
• Wing Area: 241 ft²
• Gross Weight (landplane): 3,249 lb
• Gross Weight (seaplane): 3,593 lb
• Top Speed: 176 mph
• Range: 420 miles
• Service Ceiling (landplane): 22,000 ft
• Service Ceiling (seaplane): 17,800 ft
• Power Plant: One 520-hp Packard 2A-1500
• Armament: Two 0.3-in Browning machine guns, or one 0.3-in Browning plus one 0.5-in Browning MG

References

1. Photos: John Shupek and Jim Hough as noted.
2. Wikipedia, the free encyclopedia. Boeing Model 15, 5 December 2009
3. Redding, Robert and Yenne, Bill. Boeing Planemaker to the World, Thunder Bay Press, San Diego, 1997, ISBN 1-57145-045-9, pp. 29