Development

For the Navy, the Boeing Type 99

The based model for the Navy aicraft was the Boeing P-12, a U.S. military pursuit aircraft used primarily by the USAAC (United States Army Air Corps). It first Flew on 25 June 1928 and was only introducted on 1930 and only retired on 1941, (used as trainer 1938-1940). This Biplane with fixed landing gear combiend fabric-covered wooden and metal structure and was powered by the Pratt & Whitney R-1340 Wasp radial engine.

It was armed with two .30 caliber M1919 Browning machine guns firing through the propeller (interrupter gear). Top speed was 189 mph (304 km/h), range an honorable 570 miles (917 km) and ceiling 27,000 ft (8,230 m). The P12 army model was later produced into two variants, the P-12E with an all-metal fuselage with stressed skin construction and the P-12F prototype with a more powerful engine, not adopted. In for what we are concerned, it was declined into the Boeing F4B, a navy version with minor modifications, especially for the F4B-1/2. The F4B-4 was completely redesigned.

The P-12 and its variants were an important intermediate, interwar model used as primary fighter until newer monoplanes arrived such as the Curtiss P-36 and later the P-40. It was known for its rugged design, excellent maneuverability for its time but never saw combat, however it played a significant role in advancing military aviation technology and training pilots in the interwar years. Several preserved examples can be found in museums today. The P-12 was the most common US Army fighter until 1940.

Transition to the F4B family

The Boeing F4B was the United States Navy’s designation for a model closely related to the Army’s Boeing P-12. It was one of the last biplane fighters produced by Boeing and represented the pinnacle of biplane design before transitioning to monoplanes. The F4B first flew on 25 June 1928 and was introduced on 1929, retired officially in 1941. Primary User was the United States Navy, fropm the deck of three carriers (Lexington, Saratoga and Ranger) and like the original, was a single-engine biplane with fixed landing gear (reinforced) a fuselage combining welded steel tubing, with wood, and fabric covering, whereas the wings had Wooden ribs with fabric covering. It was powered by the Pratt & Whitney R-1340 Wasp radial engine like for the P-12 initially. The pilot, protected by a glass windshield coulkd fire two .30 caliber Browning machine guns but the latter F4B-3/4 were armed with a .50 caliber machine gun and .3 inches LMG. It could also carry light bombs for ground-attack missions.

The F4B top speed was Approximately 186 mph (299 km/h) and range about 570 miles (917 km) with a service Ceiling of Around 25,000 ft (7,620 m) and an excellent climb Rate for its time, making it an ideal carrier-borned interceptor (pursuit in army parlance). In short the F4B-1 was a standard P12 with a reinforced structure, especially the wheeltrain, aft tailskid, and an arrestor rook at the rear plus a few more navy-related items. The next F4B-2 featured a new tailwheel replacing the tailskid, as well as improved aerodynamics and small performance upgrades. The next F4B-3 had now a new semi-monocoque fuselage structure for increased durability and better handling. and the final F4B-4 had a strengthened airframe with additional equipment, and a ring better shaped cowling for improved engine cooling, with NACA, the ancestor of NASA.

It was used for interception, patrol, and possibly light ground-attack missions. Like the army model it was highly maneuverable and reliable, preferred by pilots for its excellent flying characteristics, even above the Grumman FF and the Curtiss. It was widely used by the Navy aboard carriers but also from land-based squadrons during the early 1930s, and was versed to the USMC. Despite being a capable fighter, it was eventually made obsolete by the Grumman F2F. The F4B represents an important evolutionary step in U.S. naval aviation, bridging the gap between early biplanes and the high-performance monoplanes of WW2, with many squadron officers being trained on these. The USMC kept them longer than the USN. Preserved examples can be found in aviation museums.

The Boeing P12

US Army P12

The Boeing P-12 was a “pursuit aircraft” (interceptor) operated by the United States Army Air Corps. It was delcined into a specialized navalized variant called the F4B, used by United States Marine Corps and United States Navy. The P12 was the most important fighter in interwar US service while beign also largely exported. It was replaced by the transition ponoplane P26 “peashooter”. It sold well also internationally. Many variants were developed to test various powerplants and ducstomer’s requirements, with a total of 33 one-off aircraft. Which added to the 366 P-12 and 187 F4B amounted to a total of 586 and it is well documented through archived serial numbers.In the 21st century a handful of surviving air frames are on display in museums.

Boeing P-12E, trainer aircraft, 25th Bombardment Squadron

The Army Boeing P12 filled all the operational squadron of the USAAC from the east to the west coast, as well as Texas and New Mexico. The series started with the nine pre-prod P-12 powered by the Pratt & Whitney R-1340-7. It helped ironin out emements, and was succeeded by 90 main batch P-12B with the next Pratt & Whitney R-1340-9 and an improved NACA cowl as well as a shorter landing gear (as the initial model “bounced” a lot) and larger wheels. It was followed by another batch of 96 P-12C which had a new ring cowl and a spreader-bar landing gear.

Boeing P-12E Air Corps Reserve, 1930s

Next were 35 P-12D powered by the R-1340-17 as an other test pre-serie then the last major production batch, 110 P-12E with a brand new semi-monocoque metal fuselage and a redesigned vertical tail and tailwheels in place of skids. They corresponded rto the Navy’s F4B3/4. There was at last a batch of 25 semi-experimental P-12F powered with the Pratt & Whitney R-1340-19, which had the best power to weight ratio of the whole serie. Manufacturing code for Boeing was model 99 and so on.

P12E

P-12s were flown by the 17th Pursuit Group (34th, 73rd, and 95th Pursuit Squadrons) at March Field in California for the west coast, and the 20th Pursuit Group (55th, 77th and 79th Pursuit Squadrons) at Barksdale Field in Louisiana for the gulf of Mexico. P-12s were also sent to the 4th Composite Group (3rd Pursuit Squadron) of the Philippines as well as the 16th Pursuit Group (24th, 29th, 74th, and 79th Pursuit Squadrons) in the Canal Panal Zone, as well as the 18th Pursuit Group (6th and 19th Pursuit Squadrons) in Hawaii. They lingered into service much longer. Replacement by the P-26 started in 1934–1935 and survivors were still used for training until 1941 or/and static, assigned to mechanic’s schools. The army also spared 23 P-12Cs, P-12Ds and P-12Es as advanced trainers for the Navy as F4B-4As, without the arrestor hook.

Design and development of the F4B

The F4B was developed by Boeing as a private venture to replace the Boeing F2B-F3Bs (1928, 32+ 74) in service with the United States Navy, themselves replacing the Boeing FB (model 15). First, the company presented the XF4B-1, two initial prototypes for Navy evaluation, former Model 83 and former Model 89. Engineers managed to make it smaller, lighter and more agile while still powered by the same Wasp engine as the F3B. Top speed and performance went up as a result.

The Navy was invited for a demonstration and asked for 27 to be delivered for further evaluation. This Boeing Model 99 which first flew on 25 June 1928, two years after the F2B entered service thus as the F4B-1 with a proper split-axle landing gear and ventral bomb rack. The United States Army Air Corps, also assiting to demonstrations, ordered the P-12. So the Army ordered a model developed for the Navy, also in the assumption of its ruggedness, on top of superior performances. The army version would necessary be lighter.

The company also developed an interesting one-off for the Navy, the F4B-1A, converted to an unarmed executive transport for the Assistant Secretary of the Navy, whjch was a breveted pilot. It had a larger fuel tank moved to upper wing centre section.

F4B-1 (Boeing Model 99) 27:1928

The F4B-1 using typical construction techniques of the time. It was constructed from a welded truss fuselage, with formers and longerons creating the aerodynamic shape. Wings were of wood construction for the ribs and structure, albeit reinforced with metal parts, notably close to the struts attachments points, and covered by fabric. The ailerons were tapered and there was corrugated aluminum covering. The Pratt & Whitney R-1340 nine-cylinder radial engine was uncowled on this early version, sporting prominent cooling fairings behind each cylinder. They were were later removed in service. It seoon appeared that in heavy weather salty water sprayed and eventually ended on these engines.

F4B-2 (Boeing Model 223) 46:1929

The F4B-2 was similar to the F4B-1 but with a Townend ring cowling to better protect the engine unlike the army model. The cooling fairings behind each cylinder were not repeated either. However some crashed revealed weakness in the landing gear so a spreader bar was incorporated between the landing wheels. The tail skid tended to clog into the deck and dent the planking so it was replaced by a castoring tailwheel. For better stability it was decided also to replace the tapered ailerons for constant chord Frise ailerons. 46 were produced and the latter received the same vertical fins and rudders as the F4B as a retrofit to improve their poor directional stability.

F4B-3 (Boeing Model 235) 21:1930

F4B3 USMC

The F4B-3 was a completely new model. Instead of a fuselages in canvas wrapped welded steel tube truss, they had a new fuselage made of welded truss and semi-monocoque wooden construction, far more aerodynamic and more rigid. From the engine mount to the fuel tank bay, welded steel truss, but stressed skin and in semi-monocoque aluminum alloy up to the tail.

Wings were still structured in wood covered with doped fabric however. Power was imprpved with the adoption of the new nine-cylinder Pratt & Whitney R-1340-D rated for 500 hp. For the first time, it featured an internal supercharger. This enabled much greater climb rates and better altitude performances, making it a true interceptor. It also drove a 9 feet two-blade Hamilton Standard propeller. Its headrest fairing was also borrowoned to the P-12E, most were retrofitted with a headrest fairing that could store a liferaft and that modifications was standard on the next F4B-4.

F4B-4 (Boeing Model 235) 92:1930

F4B4 with bombs under racks

The F4B-4 was nearly identical to the F4B-3 but with a larger vertical fin for better directional stability. The fuselage and most details were from the F4B-3 and the first nine had also the same carburetor induction scheme as the F4B-3, the following had all a single oval carburetor intake on the port side. This was by far the best known and widespread of all variants. Brazil was the only one to acquire the F4B-4s, 14 ordered.

F4B-5

A detailed specification for an F4B-5 as a minor development was eventually cancelled as by 1931, monoplanes seems more in favor already.
Export models resulted in many sub-variants, some marying aspecs of the P12 and F4B, especially the later variants.

Customers

Brazilian Air Force
Chinese Nationalist Air Force
Philippine Army Air Corps
Spanish Air Force
Royal Thai Air Force operated Boeing 100E variant
United States Army Air Corps, Navy, Marine Corps

Operational History

The F4B was the most famous and popular American carrier-based fighter of its era. It was highly regarded by its pilots because of its good performance for its time. Some of the corrugated metal control surfaces contrasted with the bolted aluminum plate airframe of its predecessor, the F3B. The F4B series remained in frontline service for seven years, until 1937 when they were replaced by the Grumman FF2 fighter, it would remain in service as training aircraft until the early 1940s. This marked the end of the Boeing-built carrier-based fighter line: FB, F2B, F3B, F4B. From this point on Grumman became the preferred supplier of carrier-based fighters to the United States Navy until, throughout and beyond World War II.

U.S. Marine Corps
F4Bs were flown by two Marine squadrons: VF-10M (F4B-4s from February to July 1933. In June it was focused on Bombing, redesignated as VB-4M, under command of MAJ Roy S. Gieger, Marine Corps Aviation. They were later transferred to VF-9M at Quantico and in September reequipped with 16 F4B-3s.

The other was VF-9M, based at Brown Field, Quantico. (F4B-4s) from September 1932. In June 1933, it received the F4B-4s from VF-10M. These were flown until they fell apart litterally, in 1938 and replaced by Grumman F3F-2s. A single F4B-3 (BuNo) 8911 went to the Headquarters, U.S. Marine Corps as personal aircraft of Colonel Ross “Rusty” Rowell, Director of the Marine Corps Aviation.

The US Navy deployed from 1930 the F4B-2, B3 and B4 in particular from its aircraft carriers. It was probably used for training on USS Langley, and saw service on USS Lexington (CV-2), uss Saratoga (CV-3) as the latter were completed in 1927. When USS Ranger (CV-4) was completed in 1934, it had also squadrons equipped with Boeing F4B-4 for a time. At the time, the small carrier (15,000 tonnes) carried the same 76 aircraft as the Lexington class (36,000 tonnes). She was however slower but showed that a large air group could be based on a light carrier in order to save treaty tonnage.

These carriers kept these biplanes until 1937-38. In 1936, for example, Lexington’s air group consisted of 18 Grumman F2F-1 and 18 Boeing F4B-4 fighters, and nine F2Fs in reserve. The F4B allso allegedly was comprised in the air group of USS Yorktown (commissioned 1937), not her sisters. If so, they were present for only a short time before replacement by the Grumman F3F.

Gallery:

F4B VF6B “Felix the Cat” USS Saratoga 1931

F4B VF5B “The red rippers” USS Lexington 1932

F4B4 VF2 USS Lexington 1933

F4B3 USMC Red Devils VB4M, SanDiego 1935

F4B4 VF3B, USS Ranger, leader 5th section

F4B4 VF9M Commanding Officer “Sandy” Sandersons Personal Aircraft.

F4B4 US navy

F4B1

F4B4 USMC in formation

F4B-2 of VF 5B over Southern California in the 1930s

F4B4 closeup in museums

F4B4 landing

Src/Read more about the FB.5:

secure.boeingimages.com/
fiddlersgreen.net
museumofflight.org
airandspace.si.edu

en.wikipedia.org/wiki/Boeing_P-12
fr.wikipedia.org/wiki/Boeing_F4B
wings-aviation.ch
airwar.ru

airminded.net
commons.wikimedia.org