Armstrong Siddeley Leopard

Leopard
Type	Radial engine
National origin	United Kingdom
Manufacturer	Armstrong Siddeley
First run	1927

The Armstrong Siddeley Leopard was a British 14-cylinder twin-row air-cooled radial aero engine developed in 1927 by Armstrong Siddeley. It was the most powerful radial engine in the world when introduced.[1]

Variants

Leopard I

700 hp, medium supercharged. Direct drive propeller.

Leopard II

700 hp, geared epicyclic drive.

Leopard III

800 hp, two-valve cylinder head, direct drive.

Leopard IIIA

800 hp, geared epicyclic drive.

Applications

• Blackburn Iris
• Junkers Ju 52[2]
• Hawker Dantorp[3]
• Hawker Horsley[4]

Specifications (Leopard I)

Data from Lumsden, 2003.[5]

General characteristics

• Type: 14-cylinder twin-row air-cooled radial engine
• Bore: 6.0 in (152.4 mm)
• Stroke: 7.5 in (190.5 mm)
• Displacement: 2,970 cu in (48.6 L)
• Length: 60.85 in (1546 mm)
• Diameter: 58 in (1473 mm)
• Dry weight: 1,466 lb (665 kg)

Components

• Valvetrain: Overhead valve, four valves per cylinder
• Fuel type: Petrol
• Cooling system: Air-cooled

Performance

• Power output: 700 hp (522 kW) at 1,650 rpm at sea level
• Compression ratio: 5.00:1
• Fuel consumption: 45 gal/hr (169 L/hr) at cruise speed
• Power-to-weight ratio: 0.47 hp/lb

See also

Comparable engines

• Wright R-2600

Related lists

• List of aircraft engines

References

Notes

1. Smith 1981, p.112.
2. Single engine version only
3. Mason 1991, p. 140.
4. Mason 1991, p. 138.
5. Lumsden 2003, p.69.

Bibliography

• Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. ISBN 1-85310-294-6.
• Mason, Francis K. Hawker Aircraft since 1920 (third ed.). London: Putnam, 1991. ISBN 978-0-8517-7839-6.
• Smith, Herschel. Aircraft Piston Engines. New York, New York: McGraw-Hill, 1981. ISBN 0-07-058472-9.