[2][3][4] At the same time an extensive new factory, claimed to be one of the largest in the world, was laid down at Lostock, Bolton, some distance away from de Havilland's main aircraft plant at Hatfield.

Work on missiles began in the late 1940s, early 1950s at the Hatfield plant in facilities which had been used during the war for the development and testing of aircraft propellers.

These were the by-products of the vibration department, whose experience in electronics was, early in 1952, to provide the nucleus of a team which began the design of guided weapons: besides guided missiles, de Havilland Propellers undertook the manufacture of aircraft cold-air units, turbine-driven electric alternators, radar scanners, electronic equipment, plastic structures—even an experimental 80 ft windmill to derive electricity from the wind.

During preliminary investigations regarding the propellent system of Blue Streak, in which DHP were the prime contractors, engineers from de Havilland visited the Convair Division of the Dynamics Corporation in the United States to discuss problems associated with refuelling.

Under licence from Hamilton Standard de Havilland Propellers produced cold-air units for most types of civil and military aircraft.

The use of epoxy resin/glass fibre-reinforced plastics for airscrew spinners, blade root fairings and other components were also developed extensively by de Havilland Propellers Ltd. at their Stevenage plant.