摘要 |
This invention relates to ring-wing aircraft and is suited particularly, although not exclusively, to use in micro-unmanned air vehicles (UAV's) with ring-wings. An aircraft (10) according to the invention comprises a ring-win g (11) defining a duct (16) with a longitudinally-extending central axis (31), propulsion means (15) located within the duct and moveable aerofoils (13, 18 ) for controlling the aircraft in flight, the ring-wing being truncated obliquely at one end, that end being the rear (11b) when in horizontal fligh t, to form a ring-wing with opposed sides of unequal length. This arrangement produces centre of mass offset from the central axis of the ring-wing, the pendulum effect will ensure that the aircraft will roll so that its centre o f mass will always be at the lowest height possible when the aircraft is airborne. Therefore the aircraft has a preferred orientation, and the contro l surfaces can be oriented with respect to this preferred orientation. In addition, the oblique truncation at the rear keeps the centre of mass toward s the front of the aircraft thereby giving improved stability in all three axe s.
|