I am a mostly retired farmer with some experience in building farm machinery including air seeders, grain conveyors, grain drying aeration and the like. I have also played with quad copters for a number of years including a DJI 2+ for crop inspections. I am interested in building a flying boom type agriculture sprayer that could apply fungicide to flowering canola and wheat. The idea is to use the boom or tube, about 4.75 inches inside diameter for the frame and also contain the fungicide. It would fly maybe 6 to 12 inches above the crop at a speed of maybe 10 mph with propellers all along the tube creating a down draft to help disperse the chemical into the canopy of the crop getting excellent penetration . Most fields around here are 1 half mile long and to go back and forth I would need about 7 lbs. of product for every foot of sprayer. As an example 20 feet of sprayer times 7 lbs. per foot would be 140 lb. of product in the tube. A back and forth trip of 1 mile at 10 mph with a turn around and some hover time would take 8 minutes. That would be the right time to change batteries and a refill. The supply trailer would be a low flat bed unit with the bottom housing the water tank and the sprayer homing in on top after each run. On the farm we have an RTK GPS signal that could be used.
Now the benefits, less chemical used, having very accurate coverage with very little drift and applying during night time when bees and the like are at home. There are meany more benefits like no pilot on board.
Now is this feasible? If so, what would make it work? The technology today is almost endless with ultra sonic perception, GPS, compass, altitude, way points, 3D FPV and the like. . What would the cost to build and maintain be? An airplane here cost from 7 to 10 dollars an acre. Would like to start with 1000 acres each year.