Bristol Hercules: Radial engine, Aircraft engine, Roy Fedden, Bristol Aeroplane Company, Sleeve valve, Argyll (car), Aircraft, World War II, Bristol ... Wright R-2600, Fiat A.74, Gnome-Rhone 14N

The Bristol Hercules was a 14-cylinder two-row radial aircraft engine designed by Sir Roy Fedden and produced by the Bristol Engine Company starting in 1939. It was the first of their single sleeve valve (Burt-McCollum, or Argyll, type) designs to see widespread use, powering many aircraft in the mid- World War II time frame.