Early quad-copter RPV (drone) crop sprayer, a 1960 concept from Gloster Aircraft.
10' diameter rotors on folding arms, length 22' 10", width 20' 7", height 3'. 105hp
Potez 4E air-cooled flat-four. 20 gal spray tank, 22' spray-bar. Two operators, one
on each end of the field, control would automatically switch to whichever was closest
to prevent over-running the target field, the drone also automatically homed in on
the controllers. It was intended that it would be trailered from field to field with the
arms folded.