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In Reply to: Re: Very interesting. Will knock the fillings from your teeth no doubt... posted by dwk on October 7, 2005 at 07:21:09:
>>Time to scope out the offerings in RC helicopter linkages...How does the device operate? Is the blade pitch varied by servo control? Is the rotation speed varied per the music source as well?
"Let me help..."
Follow Ups:
In the Thigpen unit we saw at RMAF, the rotational speed is constant. I think he said a 1/3HP motor, but I'm not sure whether it's induction or dc - I'd guess induction as you can get them for a dime a dozen off the shelf. The pitch of the blades is driven by a standard magnet/voice-coil assembly connected to a standard amp (I think it was a Sumo, but I didn't look closely. Bruce wants/needs a dc-coupled amp as any AC-coupled amps roll off to early :-) ). Attached to the VC assembly are push-rods that connect to the aformentioned helicopter linkages which are attached to the blades themselves.
The one detail I don't remember is whether the magnet assembly rotated or not. I'd guess it did, as I can't imagine keeping gap tolerances to the VC if the magnet and VC were rotating wrt each other.
If I explained it well enough, you can readily understand the 'diy' reaction - brilliantly simple, but it seems to work extremely well. Watching the walls of the room pulse in-and-out was eye-opening to say the least.
BTW - I didn't hear the helicopter linkage comment directly but my friend did. I'm not sure whether that was only in the prototype or whether the 'real' unit used them or some custom linkages.
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