FB = Fighter Boeing

Boeing is perhaps best known for its multi-engine bombers and commercial airliners, but in the 1920s and 1930s the Boeing Airplane Company produced outstanding fighter aircraft for the Army, Navy, and Marine Corps.¹

Boeing’s first fighter aircraft was based in part on Germany’s Fokker D.VII biplane, one of the finest fighters of World War I. Many of that plane’s features were found in the Boeing Model 15. The Army tested the aircraft as the XPW-9, which first flew in June 1923.

The Army placed a production order for the PW-9, and the Navy followed with a 1925 contract for the plane, the first being delivered in December 1925 with the designation FB-1. The single-seat, bi-wing fighter had a top speed of 160 miles per hour and had two fixed, forward-firing machine guns, one .50-caliber and one .30- caliber.

The first FB-ls were assigned to Navy Fighter Squadron (VF) 2. Ten of the planes were assigned to the Marine Corps, nine of which went to China in 1927-28 with Marine squadron VF-10M. In early 1927 a civil war threatened foreigners in several Chinese cities as the Nationalist troops of Chiang Kai-shek fought against warlords ruling parts of the country. Four regiments of U.S. Marines—formed into the 3rd Brigade—were rushed to China to help protect foreign communities. The FB-ls of VF- 10M and planes from two other squadrons flew 3,818 sorties during the 18 months that the Marines were in China. Most of the flights were around Tientsin, keeping tabs on the opposing sides.

Although the Marine fighters never fired a shot in anger, seven of the aircraft were holed by gunfire. None was lost.

The initial aircraft were not fitted for carrier operation; later FB-series aircraft had strengthened fuselages and a cross-axle undercarriage and arresting hook. The first three FB models were convertible for twin-float operation (as were most single-engine naval aircraft of the time). There were other experimental models of the FB, with the FB-1 and FB-5 being the major production variants, the latter having a more powerful engine and increased wing stagger. The Navy-Marine Corps accepted 43 of the FB-1 through -6 models.

The 27 FB-5 aircraft had a most unusual delivery procedure. The first FB-5 flew on 7 October 1926. Before any of the others flew, all 27 of these aircraft were loaded on barges at Boeing’s water-edge factory in Seattle, Washington, and floated out to the carrier Langley (CV-1). They were hoisted aboard by crane, were accepted by the Navy on 21 January 1927, and then made their first flight from the carrier’s deck.

The FB series had in-line Curtiss piston engines. Pratt & Whitney’s development of a radial, air-cooled 400-horsepower engine would lead to the Navy’s decision to use only radial engines in carrier-based aircraft. They were easier to maintain and did not require cooling fluids.

Boeing next produced the radial engine Model 69, which first flew on 3 November 1926. The aircraft was tested by the Navy as the XF2B-1 and was quickly ordered into production. With a top speed of almost 160 miles per hour, this aircraft had two machine guns, could carry five 25- pound bombs, and was fitted for carrier operations.

The Navy ordered 33 F2B-ls, quickly followed by 74 similar F3B-ls. These fighters operated from the Navy’s three carriers in service in the late 1920s and early 1930s: the Langley, Lexington (CV-2), and Saratoga (CV-3). In addition, F2B-ls were flown by the Three Sea Hawks, the Navy aerobatic demonstration team—which flew intricate formations with the aircraft tied together!

The ultimate development of this fighter design was the F4B, flown by the Army as the P-12.² Two prototypes were built by Boeing for the Navy, one with an undercarriage axle strengthened for carrier operations, and one with a split undercarriage that could carry a 500-pound bomb under the fuselage. The Navy evaluated both XF4B-ls in 1928. The aircraft was impressive and the Navy ordered 27 production models of the carrier variant and purchased the two prototypes for upgrade to production-aircraft standards.

Aviation writer Peter B. Mersky has observed:

It was the definitive F4B model, which became the symbol of military aviation—Army (as the P-12), Navy, and Marine—in the late 1920s and mid- 1930s.

The design refinement that followed the F3B was unusual in that it did not require the installation of a more powerful engine, normally the procedure to increase performance for a newer model of the same design. Enough aerodynamic refinement—such as the addition of an engine cowling . . . and different landing gear—gave a 22 mile- per-hour increase in speed over the F3B. The XF4B-1 was also 400 pounds lighter than its predecessor.³

The successful performance of the F4B led to the Navy and Marine Corps procuring a total of 188 of four models. This was the largest Navy Department fighter buy until the Brewster F2A Buffalo, which entered service in December 1939. In addition, the Navy acquired 23 similar P-12 aircraft from the Army in 1939, which were designated F4B-4A, and one F4B-4 was built from spare parts in 1934- Thus, the grand total of F4B acquisitions was 212 aircraft.

The Boeing fighters served aboard carriers until 1938, when faster Grumman biplane fighters succeeded them. But F4Bs remained in service as utility and administrative aircraft until late 1942. Most or all of the ex-Army P-12s and other surviving F4Bs were also used as radio-controlled target drones.

Boeing continued to work in the fighter field. The F5B was a monoplane with a 500-horsepower engine flight tested in 1930; the F6B, a 1933 prototype based on the F4B with a larger engine, which was later designated BFB-1 to show that it could be used as a “bomber-fighter”; and the F7B was another monoplane flown in 1933, a 231 mile-per-hour aircraft that was unstable. By the mid-1930s Boeing designers were concentrating on multi-engine bomber aircraft; they produced the famed B-17 Flying Fortress and the superlative B-29 Superfortress.

After World War II Boeing made one more major effort to develop a Navy single-engine aircraft, the F8B, a sleek-looking fighter-attack design with a 2,500- horsepower R-4360 engine. Different models of that Pratt & Whitney engine were used in the B-36 Peacemaker strategic bomber, AM Mauler attack plane, P4M Mercator patrol plane, and Howard Hughes’ “Spruce Goose.” The F8B prototype flew on 27 November 1944. But that plane lost out in what became the Navy’s “attack” role to the Douglas AD/A-1 Skyraider and the Martin AM Mauler. Only three XF8B-ls were built.

Thus, the successful line of Boeing fighters for the Navy—from the FB to the F4B—did not continue past the 1930s. But reminders of those most-successful aircraft remain in the several Boeing fighters found in American aviation museums.