Aerial spraying of insecticide against Pine Beauty
The photograph is courtesy of the family of George Dey. George took many forestry photographs in his forestry career and many are now shown on this web site. Check under ‘Groups’ and George Dey Collection.
A closer view of the aircraft HB-FET passing over but not spraying. This aircraft was based in Switzerland but had its spraying equipment fitted, if remembered correctly, down at the south of England. John Stoakley (FC Research) worked with an Engineering Institute (Cranford?) in the fitting of spinning disc sprayers onto the aircraft. Normal sprayers had two spinning discs running about 7000rpm but in this case the assembly was bulked up to perhaps 15 or 20 discs on the one shaft and the revolving speeds increased significantly to get the volume through for flying and also crucially to achieve a very minute droplet size. The droplets spun off the tips of tiny serrations on the outer edges of the discs and were electrically charged so that they tended to stick to foliage. Testing of droplet size, calibration and volume flows took many hours of work.
There were a number of these sprayers on each side of the aircraft and some just can be seen in the photograph strapped to the rear wing support.
Groups: Aircraft in Forestry Work, Animal, Insect, Plant and Fungal species in forestry, Forestry Areas, Forestry in Action, George Dey Forestry Collection