with 25m3 (800 cubic feet) per second flow of air (at the speed of 100m/s) behind your back ? (that's a mass flow and speed he needs to get through his 0.6m fan

with 25m3 (800 cubic feet) per second flow of air (at the speed of 100m/s) behind your back ? (that's a mass flow and speed he needs to get through his 0.6m fan to get 250Kg of force for 120Kg device + 80 Kg pilot) Letting a bit of it out to caress your back doesn't seem to be a problem.