VTOL, V/STOL, and STOVL

he capability of a fixed-wing air­craft to take off and land vertical­ly is known as vertical takeoff and landing, or VTOL. Some aircraft have the ability to take off and land on a very short runway-these are V/STOL aircraft. V/STOL stands for vertical or short takeoff and landing. Still others are STOVL aircraft-they are capable of a short takeoff and vertical landing. The terms are used to describe a small group of fixed-wing aircraft. They do not include helicopters, airships, or rockets, all of which also have the ability of vertical takeoff.

Propeller Planes

Fixed-wing aircraft normally need a long takeoff run to get airborne. They cannot take off until their wings are moving through the air fast enough to create enough lift to overcome the plane’s weight. If a fixed-wing aircraft is to take off vertically, it needs to direct its engine power downward with enough force to overcome its weight.

Propeller planes can do this by tilting their engines and propellers so they work like helicopter rotors. The V-22 Osprey, a V/STOL aircraft, swivels its propeller engines up for takeoff and landing and angles them forward for regular flight. Its propellers work like helicopter rotors for vertical flight and like propellers for forward flight, so they are called prop-rotors. They are made bigger and stronger than normal pro­pellers because they must support the entire weight of the aircraft for takeoff and landing. Aircraft such as the V-22 Osprey are called tilt-rotors.