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Mitsubishi was the first and largest series producer of Japanese engines during World War II, with a 1937 Pratt & Whitney arrangement possibly contributing to this success. This 18-cylinder, two-row, air cooled aircraft engine incorporated two-speed reduction gearing, a cooling fan, and twin transverse superchargers to achieve two stage supercharging.

Four of these engines were to power the Kawasaki Ki-91 Army Experimental Long-range Bomber, which was to be larger than the Boeing B-29 and have a 4,474 km (2,796 miles) radius of action. The design of this bomber began in May 1943, and a prototype was under construction at the end of 1944, but planned production was suspended in February 1945 when tooling was destroyed during a B-29 raid before the prototype was completed. Between 1940 and 1945, a total of 2,813 Mitsubishi Ha 42 series (all models) were built.

 Display Status

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
Object Details
Date Circa World War II Country of Origin Japan Type PROPULSION-Reciprocating & Rotary Manufacturer Mitsubishi Jukogyo K. K.
 Physical Description Type: Reciprocating, 18 cylinders, 2 rows, radial, air cooled Power rating: 1,715 kW (2,300 hp) at 2,500 rpm Displacement: 54.1 L (3,300 cu in.) Bore and Stroke: 150 mm (5.91 in.) x 170 mm (6.69 in.) Weight: 1,235 kg (2,723 lb) Outside dual superchargers; Fuel injected; Cooling fan; Two-speed reduction gearing (0.588 and 0.457); Push rods for rear cylinders at the rear of the engine; Cuno-type rotary oil screen (Nakajima-type); Manufactured between 1940-45. Missing starter, generator, carburetor, spark plugs and data plate; On stand. Dimensions Other: 52 3/4 x 92 5/8in. (134 x 235.2cm)
Approximate (with stand): 160.02 x 218.44 x 161.29cm (5ft 3in. x 7ft 2in. x 5ft 3 1/2in.)
Approximate (Weight on Stand): 1551.3kg (3420lb.)
Diameter 134 cm (52.75 in.), Length 235.2 cm (92.63 in.)
 Materials Aluminum, Paint, Steel, Magnesium, Paper, Stainless Steel, Rubber, Copper
 Inventory Number A19710895000 Credit Line Transferred from the U.S. Navy Data Source National Air and Space Museum Restrictions & Rights Open Access (CCO)
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