🚀 go-pugleaf

 yee@edison.seas.ucla.edu (John Yee) writes:
|> Hello robot builders, have you any experience making small, say 6" diameter
|> maximum, hovercraft?  If so, please post/email your experiences.

Over the years I've had fairly good success building hovercraft with
just about any kind of junkbin motor.  But the best results will be
with the opposite of a cooling fan, which is designed for low noise,
long life, and high energy efficiency.  Take instead a motor designed
for a hand tool or RC model, slap a model airplane propellor on it,
and run it at 120% the design voltage (it won't last forever, of course).

(A grinding tool (e.g. Dremel) motor with a 12-inch prop can hover in 
midair like a helicopter.  It can also cost you a few fingers if 
you don't use common sense!)

Have several (4 is a good number) plenum chambers, and divide the 
airstream as close to the fan as possible.  Otherwise the hovercraft 
will be unstable, generally sitting on one side and slewing around
in circles.  It's easy to make simple skirts out of garbage bags
and attach them with a hot glue gun.  The skirted area must be divided
as well or again it'll be unstable.  

Remember that the power needed goes as the perimeter of the hovercraft,
and the payload goes as the area;  the smaller the craft, the less
efficient.  I would hesitate to build a 6" model for that reason
(my smallest model that worked well was 1'6").

--JoSH