|Type||Piston V-12 aero engine|
|First run||June 1928|
|Major applications||Hawker Horsley|
|Developed from||Rolls-Royce Kestrel|
|Developed into||Rolls-Royce R|
The Rolls-Royce Buzzard (also referred to as the H engine) was a British piston aero engine of 36.7 litres (2,240 cubic inches) capacity that produced about 800 horsepower (600 kW). Designed and built by Rolls-Royce Limited it featured 12 cylinders in a 'V' configuration of 6 in (150 mm) bore and 6.6 in (170 mm) stroke. It was manufactured in the late 1920s, but only 100 were sold. A further development was the Rolls-Royce R Schneider Trophy engine. The Buzzard was developed by scaling-up the Kestrel engine in the ratio of 5:6.
List from Lumsden.
- Buzzard IMS, (H.XIMS)
- (1927), Maximum power 955 hp (712 kW), nine engines produced at Derby.
- Buzzard IIMS, (H.XIIMS)
- (1932-33), Maximum power 955 hp (712 kW), reduced propeller drive ratio (0.553:1), 69 engines produced at Derby.
- Buzzard IIIMS, (H.XIVMS)
- (1931-33), Maximum power 937 hp (699 kW), further reduced propeller drive ratio (0.477:1), 22 engines produced at Derby.
- Blackburn Iris
- Blackburn M.1/30
- Blackburn Perth
- Handley Page H.P.46
- Hawker Horsley
- Kawanishi H3K
- Short Singapore I
- Short Sarafand
- Vickers Type 207
Specifications (Buzzard IMS)
Data from Lumsden
- Type: 12-cylinder liquid-cooled Vee aircraft piston engine
- Bore: 6 in (152.4 mm)
- Stroke: 6.6 in (167.6 mm)
- Displacement: 2,239.3 in³ (36.7 L)
- Length: 75.7 in (1,923 mm)
- Width: 30.6 in (777 mm)
- Height: 44.4 in (1,128 mm)
- Dry weight: 1,140 lb (517 kg)
- Valvetrain: Overhead camshaft
- Supercharger: Single-stage supercharger
- Fuel type: 73-77 octane petrol
- Cooling system: Liquid-cooled
- Power output: 800 hp (600 kW)
- Specific power: 0.36 hp/in³ (16.3 kW/L)
- Compression ratio: 5.5:1
- Power-to-weight ratio: 0.7 hp/lb
- Rubbra 1990, p. 59.
- Lumsden 2003, p.198.