Additionally, Saunders-Roe provided wing spars made of "compregnated wood," a high-pressure bonding method involving multiple laminations.

[6] Although originally proposed to the Air Ministry and receiving approval as primarily an engine programme, the Napier-Heston Racer was ultimately not officially sanctioned and had to proceed as a private venture with Lord Nuffield entirely underwriting the project.

[2] The first aircraft of two planned for the record attempt, registered G-AFOK (call sign Fox Oboe King),[7] had its maiden flight at Heston Aerodrome on 12 June 1940, piloted by Squadron Leader G.L.G.

[8] Recovering from the abrupt takeoff, Richmond carried out a preliminary test flight with gear extended throughout but after only five minutes airborne, while encountering inadequate elevator control, the engine overheated.

According to some accounts, Richmond was being scalded by steam from the radiator mounted below the cockpit, and in haste to carry out a forced landing, inadvertently stalled the aircraft at approximately 30 ft above the airfield.