01/31/2010. Remarks by Johan Visschedijk: "Robert T. Youngman of High Wycombe, UK, invented a full-span double-slotted flaps system to generate extra lift, which rose the interest of the Ministry of Supply. It sponsored a research aircraft, designated High Lift, to be fitted with a wing containing the new flaps system.

The possibility of modifying a Percival Proctor to carry the special wing was at first examined, but this proved impractical, so a new aircraft was built by the Heston Aircraft Co. Ltd. at Heston, to the design of Lesly E. Baynes, of the aircraft section of Alan Muntz and Co. Construction of the fuselage, engine bearers and all empennage components was done by Airwork Ltd., also at Heston. The windscreen, doors, tail wheel and main landing gear components were taken from the Proctor though.

Powered by a 250 hp de Havilland Gipsy Queen Srs.32 six-cylinder liquid-cooled inverted in-line engine and carrying the serial VT789, the High Lift was first flown from Heston Aerodrome on February 5, 1948. The following test flights conducted at the RAE Farnborough were very successful and proved the newly designed flap system to be very effective.

The High Lift was sold to Youngman in 1950, who had it registered as G-AMBL on May 10, it was flown for another four year before it was donated to the College of Aeronautics at Cranfield. The registration was cancelled on December 12, 1954."