Abstract: The invention relates to improvements with regards to the control of VTOL aircraft that use two propellers or fans as the primary lifting devices in hover. More particularly, the invention is a means for effecting control of the aircraft using just the two propellers alone, and comprises the in-flight tilting of them—which are of the conventional, non-articulated type (though they may have collective blade-pitch)—directly and equally towards or away from one another (and therefore about parallel axes) as necessary for the generation of propeller torque-induced and gyroscopic control moments on the aircraft about an axis perpendicular to the propeller tilt and mean-spin-axes. For a side-by-side propeller arrangement, therefore, their (lateral) tilting towards or away from one another produces aircraft pitch control moments for full control of the aircraft in that direction.

Abstract: A lens display assembly, which has left and right hand end members which can be supported generally upright, interlock attachments on inwardly facing surfaces of the end members in registration with one another, and spaced axially apart, transverse shelves extending between the end members, and interlock parts at opposite ends of the shelves, interlockable with the interlock attachments on the end members, so that the shelves can be supported transversely between the end members and, lens display supports on the shelves, for supporting lenses.