Brushless aircraft

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Brushless aircraft De Havilland DH.108 Swallow

Tailless aircraft are aircraft that have no other horizontal surfaces other than their main wing . In contrast to a "normal" aircraft or a canard , they do not have a separate horizontal stabilizer . Due to these structural differences, their stability properties differ significantly from those of normal aircraft.

description

Aerodynamic stability around the transverse axis

In conventional aircraft, two horizontal aerodynamic surfaces are usually arranged one behind the other. In addition to the wing, they have a tailplane . Duck planes have a canard and tandem wings have another wing. With these aircraft configurations , the longitudinal stability is achieved through the interaction of these two surfaces.

Since tailless aircraft only have one wing, this stability must be ensured in other ways. There are various possibilities:

  • Swept wings with twist . Here the outer wing tips have a smaller angle of attack than the middle part of the wing. In combination with the wing sweep, which means that the wing tips are further back, an effect similar to that of a separate elevator is achieved, e.g. B. Hoarding H IV .
  • Due to their shape, special profiles ( S-flap profile ) generate a positive (righting) pitching moment, which makes a horizontal stabilizer superfluous (e.g. Helios ). Mixed forms of both options mentioned above are possible.
  • Active regulation of the longitudinal movement. Here regulators, nowadays usually flight control computers , take over the stabilization task and adjust the aerodynamic control surfaces so that a controllable straight flight is achieved, e.g. B. Northrop B-2 .
  • The center of gravity is significantly lower than the aerodynamic pressure point. The stabilization is achieved by the large distance between the points of application of aerodynamic and weight forces , z. B. Paragliders .

special cases

  • A special case of the tailless aircraft are flying wings , which only consist of one wing. They have neither a fuselage nor a tail unit. In the parallel article “Flying wing” the technical and aerodynamic conditions of the tailless construction are described in detail.
  • Another special version of the tailless aircraft is the delta wing . The leading edge of the wing has a strong sweep , while the trailing edge is almost straight. This configuration is often found in supersonic aircraft , such as the Concorde or in military aviation .
  • A third special form can be circular wing aircraft and aircraft with extremely low aspect ratios , provided they do not have a separate horizontal stabilizer. The rare ring wings z. B. Lee-Richards Annular Monoplane can be tailless.
  • Usually tailless are designed as monoplane, in individual cases there are also configurations with two wings, which are then designed as biplanes (e.g. Burgess-Dunne AH-7 ). If the wings of a tailless biplane are offset in the direction of flight, a hybrid between a tailless aircraft and a tandem aircraft is created . One example of this is the Sunny ultralight aircraft .

Selected examples

So far around 300 tailless constructions have been built, not counting hang gliders and paragliders.

For a complete listing, see List of Tailless Aircraft

Web links

Individual evidence

  1. ↑ Karl Nickel , Michael Wohlfahrt: Tail-less aircraft. Their design and their properties (=  flight technology series . Volume 3 ). Birkhäuser, Basel et al. 1990, ISBN 3-7643-2502-X , p. 2 f .