The present invention is related to a compound helicopter with a main rotor providing lift, a pair of additional propulsion devices providing thrust and anti-torque and a fixed wing structure on each side providing additional lift during horizontal cruise flight. The propulsion devices are arranged at each side of a fuselage body with two tail booms, one arranged at each side of the fuselage body, each of both tail booms having one of both propulsion devices arranged at its boom rear end. Each of the two tail booms houses an engine and a drive shaft driving the corresponding propulsion device.