Clerget 7Z

The Clerget 7Z was a seven-cylinder rotary aircraft engine of the World War I era designed by Pierre Clerget. First appearing in 1913 it was nominally rated at 80 horsepower (60 kW). In addition to the 600 engines built in France by Clerget-Blin,^[1] 347 examples were built under license in Britain by Gordon Watney & Co Ltd of Weybridge and Gwynnes Limited of Hammersmith.^[2]

A French twin engine Caudron G4 fitted with Clerget rotary engine

7Z
Type	Rotary engine
National origin	France
Manufacturer	Clerget-Blin
First run	1913
Major applications	Avro 504
Number built	600 (French production) 347 (British production)
Developed from	Clerget 7Y

Applications

• Avro 504
• Beardmore W.B.III
• Bristol S.S.A.
• Caudron G.4
• Mosca-Bystritsky MBbis
• Royal Aircraft Factory B.E.8a
• Royal Aircraft Factory S.E.2
• Royal Aircraft Factory S.E.4
• Sopwith Pup
• Weymann W-1

Specifications (Clerget 7Z)

Data from Lumsden and Gunston.^[2][3][4]

General characteristics

• Type: Seven-cylinder air-cooled rotary engine
• Bore: 120 mm (4.72 in)
• Stroke: 150 mm (5.91 in)
• Displacement: 11.88 L (724.96 cu in)
• Diameter: 914 mm (35.98 in)
• Dry weight: 106 kg (234 lb)

Components

• Valvetrain: 1 each overhead inlet and exhaust valves operated by pushrods and rockers
• Fuel system: Bloctube carburettor
• Fuel type: Gasoline with Castor oil lubricant
• Oil system: Castor oil mixed with fuel
• Cooling system: Air-cooled

Performance

• Power output: 70.84 kW (95 hp) at 1,300 rpm (maximum power)
• Specific power: 0.1314 hp/cu in (5.98 kW/L)
• Compression ratio: 4.3:1
• Specific fuel consumption: 0.564 L/kW/hour(0.74 pt/hp/hour)
• Oil consumption: 0.0762 L/kW/hour (0.1 pt/hp/hour)
• Power-to-weight ratio: 0.67 kW/kg (0.406 hp/lb)

See also

• Clerget aircraft engines

Comparable engines

• Gnome Omega
• Gnome Lambda
• Anzani 10-cylinder
• Le Rhône 9C

Related lists

• List of aircraft engines