 The elevator control circuit was designed by Heston Aircraft Company's Chief Draughtsman, C.G.W Ebbutt, with a variable ratio- with the stick near the neutral position, large movements could be made with small resulting pitch movements.This was needed for accurate handling at low level and high speed (the 3 km airspeed record course had to be flown under 100 ft above sea level).Towards the ends of the control column movement, the ratio increased to allow utilisation of the full range of elevator travel.