Yamaha Remotely Piloted Vehicle

Registration: BAPC 447
Country of origin: Japan
Built: Japan, 1985
Manufacturer: Yamaha Motor Company
Engine: One Yamaha piston engine

Type: Remotely Piloted Vehicle

Note: Experimental remotely piloted vehicle for crop spraying.

Details: This experimental helicopter was built in 1985-86 to meet a requirement for aerial crop spraying, in particular small Japanese rice paddies which are often difficult to accurately spray with conventional aircraft. The Yamaha design was funded by Fisons, a major UK chemicals company.

Fisons had been involved in agricultural spraying trials since the late 1940s using full-size helicopters in East Anglia. Their new project scaled up a conventional model helicopter layout using a water-cooled 12hp/100cc powerplant. It was preceded by a smaller helicopter based on the Kalt Baron built in 1984 and powered by a 1.5hp engine. This model had a rotor diameter of 1.8m (6ft) and a gross weight of 11kg (24lb). Payload was approximately 6kg (13lb).

The full-scale Yamaha Remotely Piloted Helicopter's (RPH) empty weight was approximately 37kg (79lb) with the front-mounted spray bars included and it could carry a payload of approximately 10kg (22lb). Auxiliary tanks were fitted to carry the crop spraying chemicals. Flight trials during July 1986 showed up a number of handling problems, in particular when trying to spray in a straight line, and it was eventually concluded that this was an inefficient use of chemicals and with a poor payload it did not warrant further development. The project was eventually abandoned in 1987 and Fisons donated the aircraft to The Helicopter Museum two years later, arriving in Spring 1990.

Development of a successor to this interesting prototype was continued by Yamaha during the late 1980s and offered on the market in 1990. Designated the R50, this version had a 5m (16.4ft) rotor diameter and could carry a 20kg (4.4lb) payload. It became a very successful RPH and, as new unmanned air vehicle technology and uses developed, found new markets in airborne surveillance roles for various civil agencies as well as for its original agricultural purpose.

Maximum Take-Off Weight: 47kg (104lb). Rotor Span: 3m (9.7ft). Fuselage Length: 2.7m (8.8ft). Height: 1.1m (3.6ft)