Posted by Smithy (203.38.223.82) on August 28, 2002 at 15:33:58:
In Reply to: Re: wheel update posted by grim on August 28, 2002 at 06:30:06:
G'day Grim,
Sorry for the late reply but living in Aussie land (Sydney) sort of puts us on the wrong time/space/continuum!!! Anyway you are quite right, the mechanism lifts the mass at bottom dead centre and the uses the energy stored in the spring to lift it again at top dead centre, therby in theory causing a continual imbalance, I thought of changing the timing slightly to allow for the small difference in acuation time but that will have to wait untill I can have the whole unit assembled. To answer your question the bearings I have are left over from overhauled small turbine engine fuel controls,(Bell jet ranger helicopters and similar)This is what I do for a living, although used they are still in good condition and are perfect for the task at hand.
The making of the mechanisms is not too difficult, and is relatively cheap although time consuming, all the parts I have used so far are easily obtained from any hardware store!! I wish I could put some photos here so we can all see!!! Please be aware that this is NOT my idea, it belongs to ALDO COSTA and I'm only trying to replicate his mechanism. The mass weights are made of brass rod 1" in dia and 1" long ( very close to 100grams each) with an 8mm hole in the middle for the stay bar and spring holder to sit, the whole mechanism is approx 4" high and looks complicated but is really quite simple, setting up the throw distance and stops is the difficult part as I have no measurements to go off!!
Hope this sheds a little light on the subject for you.
Smithy.
: Brett according to what you gave as figures you've got almost four times the physical weight displacement off-center as Costa did. If the parts you've already made didn't bust your budget, I'd encourage you to make two more of the mechs so your wheel has at least four throw points and give it a shot. The only way that this deal is going to be solved is to theorize, draw it out, build it and try it. I still haven't quite gotten what Costa's mech was meant to do. Does it cock and lock weights in a, say upward, position off the wheel bottom and then release them later?
: I'd certainly give it a go if I were you. If you have time please explain the mech operation. Looking at Costa's drawing and having it explained to me and anyone else who is pondering it by someone who has it in their hands physically is a whole 'nother deal. Believe me I am not going to steal yours or anyone else's ideas off this site, I certainly don't have time for any of the lawsuits or litigations that would occur. You've got Costa's mech in your hands and I'm basically trying to understand what the hell he was trying to do.
: I believe the amount of offset may be the key. Mine went down in flames because of the counterweight/thrown weight ratio ended up way out of kilter, and it found an equilibrium point.
: By the way, where do you get those low-friction bearings that you spoke of? Looking forward to your reply.
: As always,
:
: grim