I have this crazy idea of building a crop dusting copter. It could be multi purpose vehicle but spraying all kinds of crops on those huge fields drives me crazy :) It could also pretty nicely fall into the concept of precision agriculture when first you do NDVI mapping and immediately you start spraying with variable rate thus saving some input costs. To save time and do faster spraying of large fields there could be several of these copters flying simultaneously. I know this is not new so far but there are few planned improvements :

- Pixhawk with 4G/LTE telemetry running control from cloud SW - fully automatic control

- electric propulsion system saving operational costs to minimum

- continual refuelling of pesticide tanks based on preprogrammed sequence (1 copter per minute etc.)

- use sonar or radar to automatically control 2m flying height above vegetation

One may continue to optimize, be creative here but enough for now. It's just an idea anyway. The disadvantage of this concept is obviously the low battery endurance due to high payload (min. 20kg). But batteries can be changed quickly. Now use multlikopter or helicopter ? If multicopter, which one ? 6 or 8 motors ? Which frame ?

The only multicopter with such payload I could find : http://kopterworx.com/shop/rtf-ready-to-fly/rtf-hammer-x8-20.html

All other options include helicopters with gas engine :

http://rmax.yamaha-motor.com.au/

http://aoxinbio.en.alibaba.com/product/1194534807-219161662/Crop_automated_spray_Pesticide_helicopter_UAV_Drone_.html

http://aeroscape.en.ecplaza.net/agricultural-acon-h-gps--343560-2703078.html

Yamaha has 20 years of experience with this. But you cannot buy that copter and they fly manually..

So what do you say ?