Before and after the R101 tragedy, Roxbee Cox worked on the development of aeroplanes at the Royal Aircraft Establishment at Farnborough. It was here that he contributed to aircraft safety with his studies on the problem of wing flutter and the stability of structures.
In the early Thirties biplanes were still common, although monoplanes were starting to prevail. At certain speeds the wings of both types of plane could oscillate because of the natural frequency of the structure. Sometimes this was so severe the wings could fail. This was known as "flutter", and was due to the flexibility of the wing-frames. Applying his framework knowledge, Roxbee worked closely with Alfred Pugsley to eliminate this problem. All new aircraft designs relied on this research, and in 1934 this was recognised when Roxbee won the Busk Memorial Prize. It was, in fact, Roxbee and Alfred Pugsley (later Sir) who coined the now common term of "aeroelasticity".
Roxbee was called back to the Royal Airship Works at Cardington as Chief Technical Officer briefly in 1931, when he was expected to work on the R100. However, the project was cancelled and he moved back to Farnborough. In 1935, he was promoted to Principal Scientific Officer in the Aerodynamics Department and by 1936 became the Head of the newly created Air Defence Department.
Letter re: flights in bombers (January 1931)
Letter to mother plus two cuttings re: Valetta Sea-plane trial (January 1931)
Letter mentioning Schneider trophy (June 1931)
Letter re: possible return to Royal Airship Works (July 1931)
Letter re: hopes for the future (July 1931)
Letter re: move to RAW as Chief Technical Officer, with press cutting (July 1931)
Letter re: bomber flight and tea with Collins (October 1931)
Letter to Cox from H. T. Tizard, Imperial College (February 1937)