Frank Barnwell and his brother Harold founded Grampian Motors in Stirling, Scotland. Their aircraft was used for the first power airplane flight in Scotland, at Causewayhead in 1909. Barnwell went on to become the chief designer at Bristol aircraft. He developed a variety of craft used by the RFC and the RAF including the F2 (a single-engine biplane fighter) and the innovative Blenheim, a twin-engine bomber and long-range fighter which incorporated such innovations as an all-metal stressed skin, retractable landing gear, and a motorized gun turret (nearly 4,500 Blenheims were built).
Despite his genius as an engineer (though it should be noted that his craft often exhibited tricky flight characteristics), Barnwell was something of a menace as a pilot. Bristol Corporation banned their 55-year-old chief engineer from flying any Bristol test aircraft. On August 31, 1938, Barnwell crashed an experimental light aircraft near Whitechurch, England and died of his injuries.