A type of VTOL aircraft
which in simplest terms is a combination airplane
Tiltrotor aircraft usually have two engines mounted in nacelles at the ends of somewhat short wings. The engines can be rotated vertically, enabling the aircraft to take off, land, and hover just like a helicopter.
By rotating the engines horizontally, the aircraft is capable of high-speed forward flight and behaves much like a standard fixed-wing airplane, capable of high-altitude flight.
Tiltrotors have numerous advantages over helicopters, notably a much longer range and higher speed.
At present the best known tiltrotor aircraft is the V-22 Osprey, which most noders may recognize as the transport aircraft from Half-Life. This aircraft is currently in production and began deliveries to the USMC in 1999.