The Renault 6Q, also called the Renault Bengali 6, is an air-cooled inverted in-line six-cylinder, aircraft piston engine, producing about 160 kW (220 hp) continuous power. It was designed and built in France and produced for more than ten years after its homologation in 1936, with large numbers built during World War II.

The de Havilland Gipsy Queen is a British six-cylinder aero engine of 9.2 litres (560 cu in) capacity that was developed in 1936 by the de Havilland Engine Company. It was developed from the de Havilland Gipsy Six for military aircraft use. Produced between 1936 and 1950 Gipsy Queen engines still power vintage de Havilland aircraft types today.