We're having fun with fans and conveyor belts, all in the same robot. Right now we've tested a 22", 3DA airplane prop. It puts out about 28 mph windspeed, and when we tried putting it on a rolling chassis alone that weighed about 90 lbs.. it started pushing it at about 3/4 speed and accelerated to a very nice speed at the end of 16ft. Here's a video of our fan testing:
http://www.youtube.com/watch?v=Sw7jg...e=channel_page
Picture of our fan casing (also known as the giant cake dish):
Picture of the fan casing being held up to the robot (this picture has all the conveyor stuff off)
We tried the fan at a 1:6 ratio, we tripped the breaker before we could even get to a decent speed. We're looking at 1:1 as a very good ratio right now. We're looking at the possibility of two non-rotating fans for directional control. 2 weeks is plenty of time....
-Greg