The Pratt & Whitney R-1340 Wasp was a reciprocating engine widely used in American aircraft from the 1920s onward. It was the company's first engine, and the first of the famed Wasp family.[1] It was a single-row, 9-cylinder air-cooled radial design, and displaced 1,344 cubic inches (22 liters); bore and stroke were both 5.75 inches.

General characteristics

• Type: Nine-cylinder single-row supercharged air-cooled radial engine
• Bore: 5.75 in (146 mm)
• Stroke: 5.75 in (146 mm)
• Displacement: 1,344 in³ (22.02 l)
• Length: 44.06 in (1,119 mm)
• Diameter: 51.38 in (1,305 mm)
• Dry weight: 805 lb (365 kg)

Components

• Valvetrain: Two overhead valves per cylinder
• Supercharger: Single-speed centrifugal type supercharger, 10:1 reduction
• Fuel system: Two-barrel Stromberg carburetor
• Fuel type: 80 octane rating gasoline
• Cooling system: Air-cooled

Performance

• Power output: 542 hp (404 kW) at 2,200 rpm at 5,000 ft (1,525 m)
• Specific power: 0.4 hp/in³ (18.36 kW/l)
• Compression ratio: 6.0:1
• Specific fuel consumption: 0.44 lb/(hp•h) (270 g/(kW•h))
• Oil consumption: 0.32 oz/(hp•h) (12 g/(kW•h))
• Power-to-weight ratio: 0.67 hp/lb (1.11 kW/kg)