Utilising the same type of construction as in the Iolaire and Sgian Dubh the Quaich is a well tried and popular layout. The aircraft is designed to be easy to handle in the air as well as on the ground. The use of a tail wheel (via the rudder pedals, operating the standard ‘push right go right’ system) combined with fairly large diameter main wheels ensures good performance into and out of short grass strips. If the take off weight is around 290kg and with a best glide ratio in the region of 12:1 then the Vto (take off velocity) will be 38.4mph and Vs (stall velocity) will be 33.2mph. These are calculated figures based on the above moderate assumptions and will improve if take off weight is lower.
The high aspect ratio wing is braced at the aerodynamic centre on the 25% chord line by a single strut to the mainspar, which is straight. The full span ailerons are differentialed 1:1.5 and have a rearward pivot point giving a Frise effect when deployed upwards. These devices help to alleviate adverse yaw. The tips of all flying surfaces have been fitted with anti vortex leading edges and tip plates to improve drag at these points.
Good all-round visibility is achieved by the low cowling and the sloping fuselage sides. Access is via the lowered port side lifting door/window. The contoured seat forms part of the structure of the main fuselage former.
The type of construction employed requires no specialist skills or machinery and could be carried out by the average handyman. The rigid flying surface obtained by all composite methods ensures a better aerodynamic package and therefore better all round performance. The wings are detachable for easy transportation. Assembly and disassembly time will be around 10 minutes.