Robert Talbot Youngman invented and patented full span flaps for small low wing airplane year 1946. Later these flaps were used in a test plane called Youngman-Baynes HL.1.
The innovative high-lift wing designed by R T Youngman was wedded to a re-designed Proctor Mk IV fuselage to evaluate fullspan slotted flaps. As VT789 the type was designated P.46 and flew on 5 February 1948 conferring excellent low speed lift. It was evaluated By RAE and later sold to the designer as G-AMBL.
Length: 29 ft 0 in ()
Wingspan: 33 ft 0 in ()
Empty weight: 2,380 lb ()
Loaded weight: 3,500 lb ()
Powerplant: 1× de Havilland Gipsy Queen 25 6-cylinder inline, 250 hp ()
Maximum speed: 180 mph