CRAFT AND METHOD FOR ASSEMBLING CRAFT WITH CONTROLLED SPIN

摘要

In craft of the type in which a fan (2) is used to direct a radial jet of air over a curved canopy (1), the canopy is shaped so as to divert the flow of air from a radial to an axial direction to produce lift. The air flowing from the fan tends to follow, depending on its velocity, a complex swirling trajectory over the canopy surface rather than a direct path and the present invention arose from a proposition that the swirling action might have an adverse effect on lift. The invention proposes the use of an aerofoil control surface (6) upstream of the lift producing surface (1) and angled away from a radial direction towards or inline with or beyond the direction of flow of fluid emanating from the impeller. By employing the invention fluid flow is redirected from a direction having a circumferential component towards a radial direction before reaching the lift producing surface. In this way it is found to be possible to improve lift and also to prevent counter spin.