Paul Lewis/GIFU, JAPAN

Two Japanese aerospace manufacturers have begun to promote the commercial use of unmanned helicopters for agricultural crop dusting and airborne surveillance missions.

Kawada Industries has developed the RoboCopter 300 based on the Schweizer 300CB and had accumulated 40h of flight time by mid-April. The company hopes to put the unmanned vehicle into production within the next 24 months, said company research and development engineer Yuji Satoh at the Heli Japan 98 conference held by the American Helicopter Society in Gifu on 21-23 April.

The basic design is powered by a single Oldsmobile four-cylinder piston engine and can carry a payload of up to 294kg for a maximum endurance of 100min. It initially plans to offer two different unmanned versions of the helicopter for agricultural spraying and aerial observation.

Kawada's AgSpray application uses two side-mounted 180 litre chemical tanks feeding a pair of spray booms. For aerial surveillance and photography, the RoboCopter has been designed to carry a four-axis gyro-stabilised infrared imager and television camera.

The helicopter is fitted with five flight control actuators remotely controlled from the ground by a command transmitter/receiver with a maximum line-of-sight range of 500m. An autonomous version is also being developed with a flight control computer and a hybrid satellite/inertial navigation system, says Satoh.

Fuji Heavy Industries, in the meantime, says it has completed flight testing of its smaller RPH 2 unmanned helicopter and plans to deliver the first machine before the end of the year. The 4.8m-long vehicle is intended for use in restricted space, where other manned or remote helicopters could not operate.

Programme engineer H Kobayashi explains: "Because many fields in Japan are small and complicated, there are some where it is difficult to spray with a manned helicopter." The 330kg gross weight machine is powered by a two-cycle 60kW (85hp) engine, driving a 4.8m-diameter twin-blade rotor.

Speed and direction is remotely controlled by a hand-held transmitter. The RPH 2 can carry a payload of up to 100kg, including 60kg of chemical pesticide, for up to 60min. Fuji says it is in advanced development of new applications for the helicopter.

Source: Flight International