Gravityisnotmyfriend

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I'm designing a tip driven helicopter. No intentions on building until I get the bugs worked out. The rotor itself will be fixed pitch and look more like wings than a rotor blade. I know a rotor blade is a long skinny wing, but think a bigger chord. The reason for this is that I don't want excessive rotor speed, but I want to be able to acheive enough lift. I'm going to mount electric motors with props at the tips of each blade to cause the blade to spin. I plan to have the entire rotor tip forward and back, left and right (like in a gyrocopter) for control. I do have a couple of issues that I need help with.
1. The battery and speed control will be attached to the body, but I need to get the wires out to the motors. Its been suggested that I use a brush system like on electric motors. This would probably work, but I think I've thought of something simpler. Could I use steel ball bearings? If the inner race were attached to the body, and the outer race was free to spin, couldn't I just attach the wires to the inner and outer races? I assume that the electricity would pass pretty freely from the inner race, to the steel balls, then to the outer race. Would there be much resistance?
2. There would probably be some tendency for the body of the craft to want to spin in the direction of the rotor blades due to friction on the main bearing. My intended fix is to attach a rudder to the bottom of the tail boom. This rudder would be in directly in the propblast (rotor wash?) from the rotor. Would this be enough to keep the model facing the direction I want? I would also include a normal rudder on the same channel for control in forward flight.

Has anyone seen a R/C craft like this? Any help or suggestions would be appreciated.
Thanks

fozzie99

Among other off the wall projects, I'm working on a driven rotor craft. The motors are on a cross bar at right angles to the rotor. I've experimented with various types of homemade slip ring arrangements.The bearing idea might pass voltage but current will be a problem. Try to stay with good conductors (copper/brass). I have an etched copper plate as supply with BBs as the pickup and it does'nt work well unless the BBs are copper plated. I used
carbon motor brushes and had very little success. The best material I've tried is berllium copper alloy strips as brushes bearing on brass rings. (Do a CHARYBDIS search on this forum.) Good luck! We need pictures!

Kwok_Yu

I was thinking of doing the same thing, but micro using pager motors. Well that's my next project. Right now I am working on a micro round the pole (RTP) control line project, which uses a homemade slip ring. You can check it out here:
http://www.rcgroups.com/forums/showthread.php?t=276012

Your idea of using ball bearings as a slip ring is a proven RTP design. You need to wash the grease out. Here are some links
http://home1.inet.tele.dk/mosgaard/rtp_gb.htm
http://www.ctie.monash.edu.au/hargra...arthy_rtp.html

Good luck.

Gravityisnotmyfriend

My Feedback: (2)

Those links are very encouraging. I wish I had more of an update, but this project has been put on the back burner. School is back in and my engineering professors seem to think that the work that they assign is more important than me creating a new type of aircraft. OK, maybe I'm being overdramatic, but I don't have the time right now, regardless. When I do get the time to tinker again, I'll post my progress.