Push-pull configuration

Dornier Do 335 push-pull aircraft.

An aircraft constructed with a push-pull configuration has a mixture of forward-mounted (tractor) propellers and backward-mounted (pusher) propellers.

An early example of a "push-pull" aircraft was the Caproni Ca.1 which had two wing-mounted tractor propellers and one centre-mounted pusher propeller.

While pure pushers decreased in popularity during the First World War, the push-pull configuration has continued to be used. The advantage it provides is the ability to mount two propellers on the aircraft's centreline, thereby avoiding the increased drag that comes with twin wing-mounted engines. It is also easier to fly in an emergency, if one of the two engines fails. Conventional push-pull designs, such as the Cessna Skymaster, have the engines mounted on the nacelle so that the aircraft's tail, suspended via booms, is behind the pusher propeller. In contrast, the WWII-era Dornier Do 335 had the pusher propeller at the rear of the fuselage.