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The AD Scout (also known as the Sparrow) was designed by Harris Booth of the British Admiralty's Air Department as a fighter aircraft to defend Britain from Zeppelin bombers during World War I.
Trials flown by pilots of the Royal Naval Air Service at Chingford proved the aircraft to be seriously overweight, fragile, sluggish, and difficult to handle, even on the ground. The project was abandoned and all four prototypes scrapped.