In 1960 Glosters undertook a highly detailed design study of a lightweight unmanned crop sprayer of unusual configuration. Basically a four-rotor helicopter, it consisted of a central box structure with four folding booms radiating from it, to form an X configuration in plan view, which carried the two-bladed rotors. This central box provided a platform for the 20 gal plastic spray tank, the 105 hp Potez 4E flat four-cylinder air-cooled engine. the central gear-box, command radio equipment, hydraulic and other systems. Guard rings were provided around the four rotor discs and the 22 ft spray-bar was carried below the two rearmost rotor booms. It was planned to carry the folded crop sprayer between farms on a special transporter towed by a Land Rover type vehicle. Two controllers were required, each taking over control of the machine as it approached across the field being sprayed and turning it back toward the other operator. In this way the machine could not overshoot the field-and possibly spray weedkiller on other crops-since it would have been always homing onto a controller rather than flying away on an outgoing course.
The advantages of this unmanned helicopter were that a simplified design, free from the stringent requirements of the Air Registration Board, was possible; most of the weight normally allowed for a pilot provided more payload; the machine could be operated direct from the spraying site with no lost time in flying to and from an airstrip; more precise spraying could be undertaken within the bounds of small fields and, of course, the risks of a fatal accident were minimal. Glosters estimated that about £40,000 would need to be spent in producing a prototype and that such a machine could be sold for £3,800 in the United Kingdom where the market was assessed at being around 150. Unfortunately, although the company made out a sound case for the production of such a machine, it did not find favour with the Hawker Siddeley Board and the project was abandoned.
Rotor diameter 10 ft, total geometric disc area 314 sq ft, length 22 ft 10 in, width 20 ft 7 in, height (excluding aerial) 3 ft.
"Gloster Aircraft since 1917", Derek N. James, 1987