Engine, Nakajima Homare 21 (NK9H, Ha45-21), 2-Row, Radial 18

Type: Reciprocating, 18 cylinders, 2-rows, radial, air cooled

Power rating: 1,491 kW (2,000 hp) at 3,000 rpm

Displacement: 35.9 L (2,195 cu in.)

Bore and Stroke: 130 mm (5.1 in.) x 150 mm (5.9 in.)

Weight: 830 kg (1,830 lb.)

The Homare (Honor) was Japan’s most-used engine in the latter years of World War II. Fan cooling, fuel injection, turbo-supercharging and water-methanol injection differed in various versions. All models suffered from unreliability, service difficulty (particularly when first entering service), and vibration.

The artifact powered the carrier based Nakajima C6N-1 Saiun (Painted Cloud) (Allied Code Name MYRT) single engine reconnaissance aircraft, which is in the museum’s collection, and is the only remaining example of this aircraft. This particular NK9H (Ha45-21) engine model also powered the Nakajima J5N1 Tenrai (Heavenly Thunder) (Allied Code Name IRVING) twin-engine experimental fighter, which was never produced, and the Kawanishi N1K2-Ja Shiden (Violet Lightning) (Allied Code Name GEORGE), probably the best naval fighter produced by the Japanese. Both of these aircraft are also in the museum’s collection. The latter aircraft was first produced as a floatplane, but was later land based to counter the U.S. Grumman F6F Hellcat and Vought F4U Corsair.