 The Avro 636 was designed in November 1934 by Roy Chadwick, Avro's chief designer as a one or two-seat fighter-trainer, and was planned to reproduce the flying characteristics of single-seat fighters.It had a similar structure to the Tutor, with a welded steel tube fuselage.The aircraft was designed to be operated as a single or two seater, with the provision for fitting two forward firing .303 in (7.7 mm) Vickers machine guns.