how to pass power thru a swash plate ?

[epkoncept]

Cross post
http://www.rcgroups.com/forums/showthread.php?t=372017#post3772427

I am trying to get electrical power across/thru the swashplate, in order to power some LED's which I plan to mount on the blade tips. Most suggestions point to placing a button battery or small Lipo on the main rotor hub. I would like to try to either pass power up through the swash with a slip ring or taking advantage of the fact that my swash plate is plastic and isolated from the Al mast. I don't think that passing 20~50mA through the bearings would damage them. Or perhaps a inductive power coupling. Does anyone know what sort of pickup coil would be needed to provide 20mA at 11V or 40mA at 5 V at 2600rpm and also what strength of magnet ? I was thinking of trying the tiny rare earth magnets used in DVD rom optical pick ups ?
EP

[Gary Warner]

Sorry no one has responded by now. I figured there would be much better ideas than mine by now...

I think the idea of using a PCB with a round trace and a 'motor com' brush contact would be the best way to do this. It's used in a 'UFO' hovering 'thing' I bought a while back and it's held up just fine. They are driving motors on these contacts, which would be much more current than your application.

Do you know how to make PCB's?

Gary
--

[Eric Brouwer]

Cross post
http://www.rcgroups.com/forums/showthread.php?t=372017#post3772427

I am trying to get electrical power across/thru the swashplate, in order to power some LED's which I plan to mount on the blade tips.
EP

Depending on the heli type/balde size, why do you not go for a set of carbon fibre blades which have build-in LEDs already. Each blade has a high-briliance led manufactured inside the blade tip, and a 3V watch type battery fitted to the blade. No balancing problems. Here is a pic of a Raptor 50 using such a set of blades.

http://myweb.absa.co.za/eric.brouwer/images/pic13.jpg
http://myweb.absa.co.za/eric.brouwer/images/pic14.jpg

[epkoncept]

Hi:
Thanks for the suggestions. I thought of a slip ring, but I wanted to avoid having another noise source on my heli. I also thought of putting a battery on the main rotor hub, but thats a bother too. I may want to put some 1W~3W LED's on the tips in the future, and in that case I would have to push ~350 mA through the contacts. Its not a high priority, but perhaps after my next big crash, I will investigate pushing power through the swash plate as mine has a plastic housing.

Are the LED's on your Raptor, bright enough to see in the daytime ?
EP

[Eric Brouwer]

Epkoncept

They are not that bright during the day. However, when hovering at eye level, they are highly visible.

[TMorita]

I don't think you need a slip ring.

Metal shaft = one conductor.

Metal swashplate with plastic swashplate ball = other conductor.

Toshi