GB575538A - Improved tailless all-wing aircraft - Google Patents

Abstract

575,538. Tailless aircraft. LACHMANN, G. V. March 23, 1944, No. 5409. [Class 4] A tailless aircraft with swept-back wings 11 comprises a centre-section 10 of ellipsoidal or similar shape constituting the effective part of the lift surface and a substantial portion of the volume of the complete wing, the centre of gravity of the aircraft and the geometric centre, i.e. centre of area, of the plan view of the centre-section being both situated approximately at the point of maximum thickness of the centre-section. In plan form, the centre-section is substantially hexagonal, the forwardly pointing angle being less than the rearwardly pointing one, transverse sections approximating to ellipses with increasing horizontal axes rearwardly from the nose. The cockpit is located in the nose of the machine where the bounding surfaces are approximately spherical. Fuel tanks 12, 13 may be disposed in the centre-section 10 and wings 11, so arranged that the centre of gravity a of the aircraft does not shift to any material extent as fuel is consumed during flight. Lift flaps 14, Fig. 5, may be provided over that portion of the span where the aerodynamic centre curve - e is forward of the centre of gravity and elevons 15 at the outboard portions of the wings. In the arrangement according to Fig. 6, split flaps 141, 16 are provided, the chords of the inner flaps 141 being as nearly as possible a constant fraction of the corresponding wing chords. The trailing edges of the inner flaps may coincide with the trailing edge of the wing, and the outer flaps may be set forwardly of the inner flaps. Boundary layer control may be applied to the flapped portion of the wing, either by sucking air from the boundary layer or by injecting air or gas into the layer, particularly at the thickest part of the centre-section, in order to accelerate boundary layer flow. Specification 344,653 is referred to.