Air brake (aeronautics)

Source: Wikipedia, the free encyclopedia.
Not to be confused with Aerobraking.
Not to be confused with Air brake (road vehicle).
BAe 146-300
Convair F-106 Delta Dart air brake deployed
F-16 Fighting Falcon showing its split speed brakes inboard of the stabilators
or "tailerons"
F-15
landing with its large dorsal air brake panel deployed
Extended DFS type air brakes on a Slingsby Capstan

In

flight control surface used on an aircraft to increase the drag on the aircraft.[1] When extended into the airstream, air brakes cause an increase in the drag on the aircraft. When not in use, they conform to the local streamlined profile of the aircraft in order to help minimize drag.[2]

Air brakes differ from

stall speed.[3]

History

In the early decades of powered flight, air brakes were flaps mounted on the wings. They were manually controlled by a lever in the cockpit, and mechanical linkages to the air brake.

An early type of air brake, developed in 1931, was fitted to the aircraft wing support struts.[4]

In 1936,

gliders
were equipped with spoilers on the wings in order to adjust their angle of descent during approach to landing. More modern gliders use air brakes which may spoil lift as well as increase drag, dependent on where they are positioned.

A British report[6] written in 1942 discusses the need for dive brakes to enable dive bombers, torpedo bombers and fighter aircraft to meet their respective combat performance requirements and, more generally, glide-path control. It discusses different types of air brakes and their requirements, in particular that they should have no appreciable effect on lift or trim and how this may be achieved with split trailing edge flaps on the wings, for example. There was also a requirement to vent the brake surfaces using numerous perforations or slots to reduce airframe buffeting.

A US report[7] written in 1949 describes numerous air brake configurations, and their performance, on wings and fuselage for propeller and jet aircraft.

Air brake configurations

Often, characteristics of both spoilers and air brakes are desirable and are combined - most modern

Reverse thrust is also used to help slow the aircraft after landing.[8]

A Fokker 70 of KLM landing with speed brakes deployed.

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 (

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-18 Hornet and other fighters have an air brake located just behind the cockpit
.

Split control surfaces

Space Shuttle Discovery on landing, showing its rudder deployed in speed brake mode

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.[9]

See also

References

  1. ISBN 9780850451634
    .
  2. ISBN 978 0 521 88516 4
    , p.283
  3. ^ "Speed brake". Britannica. Retrieved 28 December 2019.
  4. ^ "Air Brakes for Planes Greatly Reduce the Landing Speed". Popular Science. Vol. 122, no. 1. January 1933. p. 18.
  5. ISBN 9781853672620
    .
  6. ^ Davies, H.; Kirk, F. N. (June 1942). "A Résumé of Aerodynamic Data on Air Brakes" (PDF) (Technical Report). Ministry of Supply.
  7. ^ Stephenson, Jack D. (September 1949). "The Effects of Aerodynamic Brakes Upon the Speed Characteristics of Airplanes" (PDF) (Technical Note). NACA.
  8. ^ "Spoilers And Speedbrakes - SKYbrary Aviation Safety". www.skybrary.aero. Retrieved 2019-12-28.
  9. ^ "Extract from NSTS Shuttle Reference Manual (1988): Space Shuttle Coordinate System – Vertical Tail". NASA. Archived from the original on 7 December 2021. Retrieved 25 October 2012.

External links

Media related to Air brakes (aircraft) at Wikimedia Commons

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