Hi

John did use a fan system for Beta but found the losses of the drive too much the other problem he had was the robot sucked the arena floor up! But this didn't stop him sticking the robot to the Garage door or something like that.
A feather should be OK. You could use a standard ducted fan with about 1000 grams thrust. if the unit was shock mounted it should be OK.
The Gimson motors are rated at 14.4v I think, add 50% to this and I make it just over 20v I don't like over volting things like motors personally as they tend to brake more frequently but everyone here is into POWER :shock: I would add Tron works well as a pusher with four 9.6v drill motors running at about 12v.
I don't think I would make this robot as it doesn't interest me enough I would like to make a fighting walker featherweight next