A Yamaha RMAX hovers over a UC Davis experimental vineyard. AUVSI photo.

By Brett Davis



It only took about 20 minutes. A group of Yamaha employees removed the small, unmanned helicopter from a white van, flew it up and down rows of wine grapes, spraying all the while, and then landed again.



The RMAX helicopter flew down a row, stopped, and flew back, never even turning around. It performed as intended, an act that was, as Yamaha’s Steve Markofski readily admitted, “boring.”



Yamaha, working with the University of California, Davis, has been demonstrating the utility of the RMAX for aerial spraying at a university-owned vineyard for more than two years. 



On 15 Oct., Yamaha and AUVSI brought a group of reporters to the site to demonstrate the speed with which the spraying function can be performed. The helicopter sprayed only water on this particular day, but the operating method was the same. 



The three-person crew included a pilot, an assistant and a spotter. The operator flies the machine, the assistant replaces spray cans or other payloads when needed, and the spotter makes sure the vehicle flies where it’s supposed to.



“We are piloted. We have a pilot. We are not autonomous,” says Markofski, who handles new business planning for Yamaha Corp. in the U.S. “We have three sets of eyes on the RMAX at all times.”



Yamaha’s RMAX handles almost all of the aerial spraying in Japan, working the same way that was demonstrated at the UC Davis facility, with a three-person crew. Crops in Japan tend to be smaller than in the United States, with houses and other obstructions nearby. Crops in the Midwest of the United States aren’t like that, but vineyards in northern California are very similar, so Yamaha thought it made sense to try RMAX there.



Napa Valley doesn’t use manned aircraft for spraying, instead relying on ground tractors. Spraying crops with those can take much longer — tractors can travel only about three miles per hour, while the RMAX can move along at 12 to 15 miles per hour. 



The company has filed for a 333 exemption from the Federal Aviation Administration to allow it to conduct commercial operations in Napa Valley, which, if approved, could start next year.



The company has been flying over the flat land of the UC Davis facility, but it’s really looking toward the nearby hillsides, where spraying is even more treacherous. That work sometimes has to be done by people carrying backpacks full of chemicals in areas too steep for the tractors.



“We think our first steps are going to be up in these hillsides,” says Markofski.



RMAX, originally designed in the 1980s, began commercial operations in Japan in 1991 and has been flying ever since. It’s 9 feet long and weighs 220 pounds with fuel and payload. Yamaha has a more advanced version, the Fazer, which has a four-stroke engine instead of the RMAX’s two-stroke, but for commercial purposes in the United States it’s initially sticking with the venerable RMAX.



Ken Giles, a professor at UC Davis’ Department of Biological and Agricultural Engineering, has worked in the field of aerial spraying since the 1980s, and with Yamaha for a little more than two years. 



“This is a technology that’s a little complex, and you’ve got all the aviation overhead, and you’ve got all the UAV overhead, and when you start spraying chemicals you’ve got all the overhead of the chemical application. So there’s a lot of moving parts and it’s just got to be sorted out,” Giles says. “The ultimate driver on all of this is economics.”



He says when UC Davis first started working with Yamaha, privacy questions were prevalent, but now the attention has shifted to the economics of using an unmanned aircraft instead of manned systems.