Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: S. Karim on July 16, 2007, 04:01:44 PM

Title: what do i need to make a propeller spin super fast?
Post by: S. Karim on July 16, 2007, 04:01:44 PM: ok i have a basic propeller facing the ground, im looking to make this spin so fast it generates enough lift below it to "hover" off the ground.

are there any lightweight motors i can get made for this kind of stuff? what kinds of rpms am i looking for? is it possible that a company would be selling gearboxes made for speed rather than for reduction (torque)?

any general to specific info is helpful. im making a hovercraft to float off the ground, using 3 propellers but im not sure about the motors ill need and what kind of electronics/battery with it.

thanks!
Title: Re: what do i need to make a propeller spin super fast?
Post by: dunk on July 16, 2007, 05:07:08 PM: you probably want to look at electric RC aircraft motors for something this specialised.
try asking on a RC aircraft forum as those guys will know far more about it than any one here.

i say this product a while back:
http://www.skyhooks.ca/kp.htm#KP44 (http://www.skyhooks.ca/kp.htm#KP44)
maybe it is what you are looking for?

dunk.
Title: Re: what do i need to make a propeller spin super fast?
Post by: KambeiX on July 16, 2007, 06:21:10 PM: hmm for fast motors use a brushless one or a normal ungeared or light geared dc motor as they are cheaper. airplane R/C stores should give you more info on the output power and power/weight rating.

For battery, LiPo are the lightest.
Title: Re: what do i need to make a propeller spin super fast?
Post by: hgordon on July 17, 2007, 07:08:16 AM: Look at http://www.rcgroups.com/vtols-360/ for suggestions
Title: Re: what do i need to make a propeller spin super fast?
Post by: Admin on July 22, 2007, 11:21:54 AM: Quote
ok i have a basic propeller facing the ground, im looking to make this spin so fast it generates enough lift below it to "hover" off the ground.
When you say hover, do you mean like a helicopter, or a robot sitting on top of an inflated bag (hovercraft)?

If a helicopter, dunks ducted fan suggestion wont work:
Quote
At 32g of thrust it will draw 2.8 Amps. Its weight is 32g.
Title: Re: what do i need to make a propeller spin super fast?
Post by: dunk on July 22, 2007, 05:34:56 PM: Quote
If a helicopter, dunks ducted fan suggestion wont work:
Quote
Outside Dia. 46mm, inside diameter 44mm (1-3/4"). The body length is 36.5mm and the nose come protrudes an additional 8.5mm Capable of providing 82g of thrust on 4.8 VDC. Minimum tailpipe diameter is 38mm, with a maximum 6? taper. At maximum thrust, this little fan will draw 8 Amps. At 32g of thrust it will draw 2.8 Amps. Its weight is 32g.

doesn't leave much space for batteries and other components but an impressive little fan never the less.

dunk.
Title: Re: what do i need to make a propeller spin super fast?
Post by: Admin on July 22, 2007, 05:56:53 PM: It appears I cant read . . . lol :P