Nakajima Homare (NK9C, Ha45-12) Model 12, 2-Row, Radial 18 Engine

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

Power rating: 1,361 kW (1,825 hp)

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

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

Weight: Unknown

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 Yokusuka P1Y1 Ginga (Milky Way) (Allied Code Name FRANCES) twin- engine aircraft, which is in the museum’s collection, for low-altitude torpedo and dive-bombing attacks. Several of these aircraft carried out Kamikaze suicide attacks against American warships. This particular NK9C (Ha45-12) engine also model powered the Aichi B7A2 Ryusei (Shooting Star) single engine torpedo bomber (Allied Code Name GRACE), the largest and heaviest Japanese carrier-based aircraft to fly in World War II, and is similarly in the museum’s collection.