World War Photos

Goodyear F2G-1 Super Corsair in flight September 1945

This version was created as result of the desire to convert the Corsair into an effective interceptor that could defend the US fleets from Japanese attacks. The new variant was equipped with Pratt & Whitney R-4360 engine and could quickly dimb to high altitudes to intercept Japanese planes. The new engine necessitated changes to the cowling of the aircraft, making it instantly recognisable. However, production of the F8F Bearcat meant that the F2G-1 never entered service.

The Pratt & Whitney R-4360 “Wasp Major” was a pinnacle achievement in air-cooled radial engine design, representing the culmination of piston engine development during World War II. Despite missing operational use during the war, it stood out for its innovative features and impressive power output.

Design and Development

1. Specifications and Configuration:

   • Bore and Stroke: The R-4360 shared the same bore (5.75 inches) and stroke (6.0 inches) as the R-2800 engine.
   • Cylinder Configuration: It featured 28 cylinders arranged in four rows of seven, giving a total displacement of 4363 cubic inches (71.5 liters).

2. Cooling and Cylinder Layout:

   • The engine’s design included a helical arrangement of the cylinders, which was a novel approach to ensure adequate cooling for the rear rows. This arrangement allowed cooling air to reach the rear cylinders more efficiently.

3. Crankshaft and Rods:

   • The crankshaft was a one-piece, four-throw forged design supported by five plain bearings. The use of split master rods, similar to those in the R-1830, allowed for this configuration. These rods were held together with four bolts and included silver-plated shims to reduce fretting.

4. Cam Plates and Valve Arrangement:

   • The R-4360 employed five identical cam plates with three lobes each, necessitating 6:1 reduction gearing. The valve arrangement was unconventional, with valves aligned longitudinally along the engine’s centerline, enhancing the engine’s breathing capabilities.

5. Supercharging and Induction:

   • The engine featured a single-stage supercharger with a variable drive up to 7.52:1, and a Bendix PR-100 four-barrel carburetor provided fuel. The intake manifold design enabled a straight path for the air-fuel mixture, improving engine efficiency.

6. Propeller Reduction Gearing:

   • The propeller reduction gearing was a planetary type, similar to the R-2800 C-series, with 15 pinions to handle the high power output. It included a torquemeter for measuring torque or brake mean effective pressure (BMEP).

7. Ignition and Crankcase:

   • The engine used high-tension ignition with seven magnetos mounted on the nose case, each serving a group of four cylinders. The crankcase was a conventional five-piece aluminum forging, similar to earlier Pratt & Whitney designs.

Initial Development and Testing

• The R-4360 utilized many components from earlier Pratt & Whitney engines, such as R-2800 cylinders and R-1830 parts, to expedite development. Initial testing began in April 1941, just eight months after the project commenced. The first test flights were conducted using a Vultee Model 85.

Significance and Impact

• The R-4360 “Wasp Major” was one of the most powerful piston engines ever mass-produced, with an initial power rating of 3000 hp at 2700 rpm. Its advanced design and large displacement made it a remarkable engineering feat. Although not used in combat during World War II, the engine found post-war applications in various military and civilian aircraft, demonstrating the high point of air-cooled radial engine development before the advent of jet engines.