The Norton NR642 (Originally the Aerotor 90) is a British aircraft engine that was designed and produced by Norton Motorcycle Company in the 1990s for use in light aircraft (particularly by amateur constructors) and UAVs.^[1]

The NR642 is a twin-rotor Wankel engine.^[1] It is a 588 cc (35.9 cu in) displacement^[2] petrol engine design, with a heavy-duty^[1] 2.94:1^[2] reduction gearbox. Cooling is provided by a fan for the rotors, plus liquid cooling for the housing.^[1][2] It was designed to meet JAR-E^[2] and FAR 23 regulatory requirements.^[1] Norton aimed for 1,500 hours running time between overhauls but was initially specifying 200-300 hours.^[2]

The NR642 first flew in late 1989, with two units installed on a Rutan Long-EZ to create what its builder called a "Twin EZ".^[3]

• Aircorp Bushmaster
• Rutan Long-EZ

Data from Lambert 1991, p.709

• Type: Two rotor Wankel aircraft engine
• Displacement: 588 cc (35.9 cu in)^[2]
• Length: 702 mm (27.6 in)
• Width: 457 mm (18.0 in)
• Height: 444 mm (17.5 in)
• Dry weight: 64 kg (141.1 lb)

• Fuel type: petrol
• Cooling system: air-cooled rotors, liquid-cooled housing
• Reduction gear: 2.94:1^[2]

• Power output: 90 hp (67 kW)
• Fuel consumption: 5.2 US gal (19.7 L)/hour^[2]
• Specific fuel consumption: 0.50 lb (0.2 kg)/hp at 70% power^[2]
  0.55 lb (0.2 kg)/hp at full power^[3]

Related lists

• List of aircraft engines

• Lambert, Mark; Munson, Kenneth; Taylor, Michael J.H., eds. (1991). Jane's All the World's Aircraft 1991-92 (82nd ed.). Coulson, Surrey, UK: Jane's Information Group.
• Mill, Nigel (April 1989). "Rotary-Mill Renaissance". Flying. Vol. 116, no. 12. New York: Diamandis Communications.
• "Rotary Power by Norton Motors". Flying. Vol. 116, no. 3. New York: Diamandis Communications. December 1989.