On 3 April 1935, the prototype was transferred to the Royal Air Force (RAF), receiving the designation K5200, and commenced operational evaluations of the type.[5] Around the same time, Gloster proceeded to plan a further improved version, featuring an 840 hp (630 kW) Mercury IX engine, a two-blade wooden fixed-pitch propeller, improved wheel disks and a fully enclosed cockpit.[8][5] K5200 was later used to trial modifications for production aircraft, such as the addition of a sliding hood for the pilot.[5]