In this Wednesday, Oct. 15, 2014 photo, the Yamaha RMax unmanned helicopter sprays water over grapevines during a demonstration of its aerial application capabilities at the University of California, Davis' Oakville Station test vineyard in Oakville, Calif. Researchers at UC Davis have been studying the effectiveness of the drone's ability for spraying pest control and nutritional materials on the test vineyard in California's Napa Valley.