Boeing F4B

The Boeing F4B was the last Boeing biplane fighter to be produced for the US Navy, and the final variant, the F4B-4, was also the last production Boeing biplane fighter for any customer.

The F4B was originally developed as a private venture. Work started early in 1928 on a new fighter that Boeing hoped would replace the F2B and F3B in Navy service and the PW-9 in Army service.

Boeing F4B-2 of VF-6B, 17 July 1931
Boeing F4B-2 of
VF-6B, 17 July 1931

The two prototypes were single span biplanes with a redesigned wing plan. The first generation of Boeing fighters (from the PW-9 to the F2B) had tapered wings, with a significantly smaller lower wing. The F3B had equal-cord wings, with a straight lower wing and a swept-back upper wing, mounted ahead of the lower wing.

The Model 83 and Model 89 both had constant-chord un-swept wings. The upper wing was larger both in span and in chord, and was mounted ahead of the lower wing. The different in wing lengths wasn't as big as on the earlier fighters.

Construction was standard for the time, with a bolted aluminium tube framework for the fuselage and wooden frame for the wings, both covered with fabric. The tail unit was braced and had a fixed tailskid.

Both aircraft were powered by a Pratt & Whitney E-1340 radial engine.

The Model 83, which made its maiden flight on 25 June 1928, had a spreader-bar main undercarriage, with vee-bracing struts connected to the middle point of the bar, and carrier arrestor gear.

The Model 89, which made its maiden flight on 7 August 1928, had a divided axle main landing gear, and could carry a 500lb bomb under the fuselage.

Boeing F4B-1 over Pensacola, 1930s
Boeing F4B-1 over Pensacola, 1930s

In the summer of 1928 both prototypes went for Naval tests at Anacostia, Maryland, where they were known as the XF4B-1. The Model 89 was also tested by the Army at Anacostia, and the type was ordered for the USAAC as the Boeing P-12. The Navy also ordered it into production, as the F4B-1. Development of the Army and Navy versions would overlap after that, and features introduced for one service would often appear on the next version for the other. Both of the prototypes were later delivered to the Navy as standard F4B-1s.

The Navy ordered a total of 182 F4Bs, made up of 27 F4B-1s, 42 F4B-2s, 21 F4B-3s and 92 F4B-4s.

Service

The F4B-1s were split between two squadrons - VB-1B (bomber) and VF-2B (fighter).

The 46 F4B-2s were delivered between January and May 1931 and went to VF-6B (Saratoga) and VF-5B (Lexington).

The F4B-3 was used by VF-1B and VF-3B (Saratoga) and by the US Marine Corps.

Seventy F4B-4s were used by the Navy and twenty-one by the Marine Corps. The Marine aircraft served with VMF-10 on the West Coast, then VMF-9 at Quantico.

The Naval aircraft were used by five squadrons (two of which changed names). VF-1 operated in on the USS Langley from 1935-1936. In 1937 the squadron operated its F4B-4s on the Enterprise, first as VF-8 then as VF-6. VF-2 used the F4B-4 on the Lexingtonfrom 1934-35. VF-3 had it on the Langleyfrom 1932-34 then the Ranger from 1934-35. VB-5 operated it on the Ranger from 1934-35 then on the Lexingtonfrom 1935-1937. In July 1937 it became VB-2 (still Lexington) and kept the F4B-4 until November. Finally VF-6 operated the type on USS Saratoga from 1932 to 1936.

The F4B-4 remained in front line service until 1938 when it was replaced by the Grumman biplanes.

F4B-1 (Model 99)

The Navy placed an order for twenty seven F4B-1s (Boeing Model 99). These combined the arrestor gear of the Model 83 with the divided axle main landing gear and bomb attachments of the Model 89. The first of the F4B-1s was flown on 6 May 1929 and they were all delivered between 19 June and 22 August 1929.

The F4B-1 was powered by a 500hp Pratt & Whitney R-1340-8 radial engine, rated at 500hp at 6,000ft. The aircraft were built with individual cowlings for the cylinders, but these were soon removed to improve engine cooling. Ring cowlings was added later. The F4B-1s were later given the larger vertical tail surfaces designed for the F4B-4. The F4B-1 used tapered ailerons.

F4B-1A (Model 99)

The F4B-1A was the designation given to one of the F4B-1s after it was converted into an executive aircraft for David S. Ingalls, Assistant Secretary to the Navy (Ingalls was the only US Navy ace of the First World War). The F4B-1A was unarmed and was painted blue to mark it as belonging to the Naval Executive. 

F4B-2 (Model 223)

The F4B-2 was the Navy's version of the P-12C (Model 222). The F4B-2 used Frise-style ailerons (designed to reduce the amount of resistance to the controls when flying at high speed). They were built with a ring cowling for the Pratt & Whitney engine. The landing gear was altered, to a spreader-bar type similar to that used on the Model 83. The tail skid was replaced with a tail wheel. As with the F4B-1, the F4B-2s were later modified with the larger vertical tail of the F4B-4. The Navy ordered 46 F4B-2s, and deliveries began on 2 January 1931.

F4B-3 (Model 235)

The F4B-3 saw a major change to the design of the aircraft. Boeing designed a new fuselage, replacing part of the welded steel tube and fabric construction with a metal semi-monocoque structure. This aircraft, the Model 218, became the prototype for the F4B-3 and the Army's P-12E. The Navy ordered 21 F4B-3s on 23 April 1931. The first aircraft was delivered on 24 December 1931 and the last on 20 January 1932.

F4B-4 (Model 235)

The F4B-4 was the final production version of the F4B/ P-12 family and the final production biplane fighter to be built by Boeing (later experimental designs weren't ordered into production). The F4B-4 had the semi-monocoque of the F4B-3, but also had larger vertical tail surfaces. This feature was later retro-fitted to older aircraft. The F4B-4 could carry two 116lb bombs, one under each wing. The Navy ordered 92 F4B-4s. The last 45 had an enlarged head-rest with a life raft stored in the extra space.

The F4B-4 was ordered on 23 April 1931, alongside the F4B-3 (the first 21 aircraft from an order for 75 were completed as F4B-3, the rest as F4B-4). The first aircraft was delivered on 21 July 1932 after the US Navy allowed Boeing to use the first fourteen airframes to fill an export order to Brazil. The second order, which had originally been for 38 aircraft, was increased by 14 to make up for this. The last F4B-4 was delivered on 28 February 1933.

F4B-4A

In 1941 most of the USAAF's P-12Es and P-12Fs were grounded and went to training schools, but 23 went to the Navy where they were given the designation F4B-4A. They were to be used as radio controlled target aircraft.

Export

Model 256

Boeing exported 23 F4Bs to Brazil. The first 14 were producing using airframes that were being built for the Navy's F4B-4 order, after the Navy agreed to allow a delay in the delivery of the naval aircraft. These aircraft were given the Boeing designation Model 256.

Model 267

The remaining nine Brazilian aircraft were produced by matching the fuselage, tail and undercarriage from the F4B-3 with the wings from the P-12E, as the Boeing Model 267.

See P-12 article for a complete list of civil and export versions.

Stats
Boeing F4B-1 (Model 99)
Engine: Pratt & Whitney R-1340-8 radial piston engine
Power: 500hp
Crew: 1
Span: 30ft 0in
Length: 20ft 1in
Height: 9ft 4in
Empty Weight: 1,950lb
Loaded Weight: 2,750lb
Maximum Speed: 176mph at 6,000ft
Climb rate: 2.9mins to 5,000ft
Range: 370 miles
Guns: Two fixed forward firing 0.3in machine guns
Bomb load: Ten 24lb bombs under wings or one 500lb bomb under fuselage

Boeing F4B-2
Engine: Pratt & Whitney R-1340-8 radial piston engine
Power: 500hp
Crew: 1
Span: 30ft 0in
Length: 20ft 1in
Height: 9ft 1in
Empty Weight: 2,067lb
Loaded Weight: 2,789lb
Maximum Speed: 186mph at 6,000ft, 170mph at sea level
Climb rate: 2.5min to 5,000ft
Range: 403 miles
Guns: Two fixed forward firing 0.3in machine guns

Boeing F4B-4 (Model 235)
Engine: Pratt & Whitney R-1340-16 radial piston engine
Power: 550hp
Crew: 1
Span: 30ft 0in
Length: 20ft 1in
Height: 9ft 4in
Empty Weight: 2m354lb
Maximum Take-off Weight: 3,611lb
Maximum Speed: 188mph at 6,000ft
Climb rate: 2min 42sec to 5,000ft
Ceiling: 26,900ft
Range: 370 miles
Guns: Two fixed forward firing 0.3in machine guns
Bomb load: Two 116lb bombs on under-wing racks

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How to cite this article: Rickard, J (7 August 2014), Boeing F4B , http://www.historyofwar.org/articles/weapons_boeing_F4B.html

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