so the weight of the aircraft is transferred from the wings to the undercarriage. The increased weight increases the available friction force for braking. In addition, the form drag created by the spoilers directly assists the braking effect. Reverse thrust is also used to help slow the aircraft after landing. Virtually all jet-powered aircraft have an air brake or, in the case of most airliners, lift spoilers that also act as air brakes. Propeller-driven aircraft benefit from the natural braking effect of the propeller when engine power is reduced to idle, but jet engines have no similar braking effect, so jet-powered aircraft must use air brakes to control speed and descent angle during landing approach. Many early jets used parachutes as air brakes on approach (Arado Ar 234, Boeing B-47) or after landing (English Electric Lightning). Split-tailcone air brakes have been used on the Blackburn Buccaneer naval strike aircraft designed in the 1950s and Fokker F28 Fellowship and British Aerospace 146 airliners. The Buccaneer air brake, when opened, reduced the length of the aircraft in the confined space on an aircraft carrier. The F-15 Eagle, Sukhoi Su-27, F-18 Hornet and other fighters have an air brake located just behind the cockpit. Split control surfaces The deceleron is an aileron that functions normally in flight but can split in half such that the top half goes up as the bottom half goes down to brake. This technique was first used on the F-89 Scorpion and has since been used by Northrop on several aircraft, including the B-2 Spirit. The Space Shuttle used a similar system. The vertically-split rudder opened in "clamshell" fashion on landing to act as a speed brake. See also List of aircraft braking systems Drogue parachute Railway air brake Thrust reversal References External links Aircraft controls Aircraft wing components