Posted by Rick Denney on August 01, 2001 at 11:05:10:
In Reply to: Re: rotar paddle engraving posted by Mark Moore on August 01, 2001 at 08:26:38:
I can think of good reasons to solder coins on rotor paddles, including improved grip but especially to extend them for small hands.
But the notion that the weight of the coin has any effect is, with all due respect, bad physics. Firstly, the weight of the coin is miniscule compared to the weight of the system, which means that the effect of the weight is also miniscule. And even if they coins were heavy with respect to the system, the only effect of extra weight is to slow things down. Two things fight the downward movement of the paddle: the spring and the weight of the system (in the form of inertia). The spring is what returns the paddle and valve, but weight slows that movement down, too. The only way to use weight to create faster valves is to remove it, not add it. That's why those Cerveny hollow valve rotors that I had on my cheapie Sanders were faster than the solid rotors on the Miraphone.
Now, there is something that extending the paddles does do from a physics standpoint. It increases the lever arm for the paddle, which reduces the effort required to fight the spring. It also increases the distance the finger must move, so the overall work is the same, even though the force is less. They may have the effect of allowing you to move the valve faster because it gives the paddles a lighter touch.
Rick "the engineering geek" Denney