In August 1922 the
Daily Mail newspaper offered a £1,000 prize for the longest duration flight by an unpowered, heavier than air aircraft. The competition was to be organized by the
Royal Aero Club, who chose the site (Itford Hill, on the
Sussex South Downs near
Lewes) and the date (16–21 October). This gave competitors six weeks to design, build and transport their entries. 13 arrived in time and one of these was the
Airdisco Phi-Phi, competition number 27. The Phi-Phi was an all wood
parasol monoplane. Its wing section was thick enough to allow for semi-
cantilever construction, supported centrally by two pairs of
cabane struts and two steeply rising
lift struts from the lower
fuselage longerons, though there were a pair of
drag wires from nose to
wing tip. The wing plan was unusual compared with the straight edges of most of its competitors, with a gently curving
leading edge, elliptical tips and straight
trailing edge. It had the highest
aspect ratio (13.6) of all the Itford gliders. The tip-mounted
ailerons were
horn balanced, again unusual. The Phi-Phi had a rectangular cross-section fuselage, with sides that curved in at the nose and, more gently, towards the tail. In plan the sides were straight edged, forming an elongated rhomb. A low aspect ratio, rectangular,
all-moving tailplane was hinged on the extreme rear fuselage. The
fin and
rudder formed a tilted, cropped parallelogram with a hinge line above that of the
elevator. The cockpit was immediately under the leading edge, well behind the nose. Originally the Phi-Phi had a pair of small main wheels rigidly attached to the lower fuselage directly below the cockpit and aided by a sprung, articulated
tailskid. The wheels were replaced at Itford by a pair of skids and then by skids with small wheels attached to them. ==Operational history==