Jeff Spitzer wrote:

At 08:59 AM 3/3/99 -0800, you wrote:

Archie Frangoudis wrote:

I am getting ready to make fixtures to dynamically balance
these engines, and am having some difficulty in obtaining
correct and reliable information.

You have to balance the whole assembly together.  There is no advatage to
balancing individual parts.

Balancing the crankshaft should be straight forward, but has
anyone removed the flywheel counterweight and achieved
equilibrium by moving it internally? Is there an advantage in
doing this on the rotary?

What does this mean?

In balancing the rotors, is there a

precision fixture available, or make one? Is there an advantage
on the rotary to overbalance?

The rotors are not individually balanced because they don't spin fast
enough to be an issue.  The rotors are simulated on the crank balance assy
with dummy weights.  Use the measured rotor weight with bearings and side
seals.  Add in half the weight of the apex seals. (There is good reason for
this...anybody know?) Also may want to add a few ounces for trapped oil if
you want perfect balance.

Jeff Spitzer

In actual fact the rotors are balanced. That is the milled area 
near one or more apex's on each side of the rotor. 

There is no doubt about it they only rotate at one third of the
ecentric shaft speed so rotor balance is way less critical as 
Jeff said. 

Paul 


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