General Aircraft Fleet Shadower The General Aircraft G . A . L . 38 Fleet Shadower was a British long - range patrol aircraft design of the immediate pre - Second World War period . Although the Fleet Shadower was a highly specialized aircraft that would have fitted a tactical need , its concept produced an ungainly and ultimately unsuccessful type . Design and development . The G . A . L . 38 Fleet Shadower and the Airspeed A . S . 39 Fleet Shadower were produced to meet Specification S . 23 / 37 , which came from the Royal Navy ' s " Operational Requirement OR . 52 " for an aircraft that could shadow enemy fleets at night . Three other companies were also involved initially : Percival , Short Brothers and Fairey Aviation . Following evaluation of the designs General Aircraft and Airspeed were contracted to build two prototypes each , General Aircraft contract dated 15 November 1938 . The specified performance of a successful design was a speed of 38 knots at 1 , 500 feet for not less than six hours . The design would also have to be able to operate from an aircraft carrier flight deck and hence use a folding wing configuration for easier deck storage . It would have to give good views for the observer and be quiet at cruising speed . The G . A . L . 38 and the A . S . 39 designs were similar – both high - wing aircraft with fixed landing gear using four small Pobjoy Niagara V engines spread across the wings to generate lift at low speed . There was an observer ' s position in a glazed compartment in the nose and a radio operator ' s station in the fuselage behind the pilot ' s cockpit . The aircraft was fitted with various devices to increase lift ; slotted flaps and slotted ailerons and , on the low wing sponsons , split flaps . The wings folded back , pivoted close to the fuselage , on hydraulic power . Due to development problems at Pobjoy with the Niagara V , it was decided to use the lower - powered Niagara III civil version . The first G . A . L . 38 Fleet Shadower ( also known as the " Night Shadower " ) flew on 13 May 1940 with the Niagara III engines . An innovative use of the " propwash " generated by propellers directed over the full - span flaps led to an impressive minimum speed of 39 mph ( 63 km / h ) which would have allowed the Fleet Shadower to cruise effortlessly above an enemy fleet . During testing the aircraft suffered from aerodynamic stability problems , but not as bad as the Airspeed design which was cancelled in February 1941 . The aircraft had major modification before flying again in June 1941 with the Niagara V engines ; the three tail fins having been replaced by a single large fin . With the incomplete second G . A . L . 38 being used as a spares source , test flying continued until September 1941 . In October 1941 the company was instructed to scrap the second aircraft , and in March 1942 instructions were issued to scrap the prototype as well . The concept of a fleet patrol aircraft was superseded by the wartime development of effective Air to Surface ( ASV ) radar that could be fitted in long - range patrol aircraft such as the Consolidated Liberator I . In February 1941 , the Royal Navy cancelled the project .