HI there.

I'm looking into aero brushless systems for a hovercraft project i'm embarking on, and i can't make heads or tails of what i'll actually need. Here's what I know:

I need a brushless speed controller capable of running a prop vertical to the ground at a high velocity, off of a third channel through my DX3 (a constant, automatic throttle to the vertical prop is needed)
I need a second brushless to run through the throttle function that is capable of stop-start usage with a propeller.
I need a lightweight lipo that'll run it all, give decent run times, won't bog it down, and won't explode. ever. I'll probably need the ESC's to have a lipo cutoff.

what do you all suggesT?

Try the electric section, Good luck trying to get info though. The electric guys seem to keep it a big secret. Or try [link=http://www.wattflyer.com/forums/index.php]HERE[/link]

Cheers

At the very minimum, the prop sizes used would be required to make any recommendations at all.

three inches. each


now can you start throwing specs of systems at me? eh?

What will be the weight of the craft? Or how large physically do you expect it to be?

I'll bet you'll need like a 2500mA 3-cell for the vertical and maybe a 1000mA 2-cell for the controls for a 24" diameter craft. Just a guess really.

I bet you'll come out ahead putting the vertical fan on the throttle stick and a single pusher fan on the elevator stick steered with a servo on the aileron stick.

I know you can run the ESC off the elevator (or any stick for that matter), but the stick centers with a spring, so you'll either have to open the transmitter and remove the spring or setup your trims so center stick is OFF-motor...... OR I hear they have reversible ESC's for the 4D fliers. Center stick is off motor, forward stick is motor pull and back stick is motor push. That way you'd have reverse on your hovercraft!

Would not your vertical fan speed be constant? You would size it so that it would float the vehicle at a certain speed. Your horizontal fan would control forward speed, and you would have a rudder to control direction.

Good luck, it sounds like a cool project.

Also, I believe that the vertical fan would not need to be all that big. If you are floating on curtains like a typical hovercraft, the fans are usually small compared to the propulsion fan.

Here's a site I found with some examples:

http://www.hovercraftmodels.com/

3 inch props actually makes it easy. You'll be able to use brushless inrunner motors without gear boxes, but you'll need pretty beefy ESCs.

I'd recommend checking out the parts available at Hobby City and staying with a smaller 20mm or 24mm inrunner. The Hextronic (HXT) and KD brands look like good values. Just remember that higher KV motors turn faster while lower KV motors turn larger props. I'd start with a medium KV rated inrunner like the Hextronic 2040 2900KV motor.

You'll want to mate them with 30 or 40 amp brushless speed controllers. Those 3 inch props on direct drive from an inrunner will pull a lot of current. Again, Hobby City offers some very good speed controllers at very fair prices.

I'd try running each setup from seperate 2S LiPos and then experimenting with 3S or 4S batteries if your testing indicates you need more power.

Hopefully the size and weight of these components will fit your design parameters. For turning a pair of three inch props, however, I'm confident that these are good general recommendations.

Good luck and good shopping!

i'm thinking i actually will need quite a bit of lift to get it off the ground, if i'm to be using two lipos, two motors and all the rest.

the vertical fan will be a non-linear controlled speed. you have off, on, and accelerate with the grip button A. off would be brake essentially...

i'll have a look around and see how i go. cheers for advice fellers