Yep! saw your response but couldn't quite
understand it ( my problem, not yours).
I did have to laugh about the balancer's
comments - but I do like the reverse engineering of Lynn's suggestion.
I'm glad you got yours right though.
----- Original Message -----
Sent: Wednesday, October 07, 2009 4:04
PM
Subject: [FlyRotary] Re: Balls and
Springs
Lynn,
Thanks, I have spun up the rotor in a lathe and
filled the rotor with coolant from a spray bottle, being careful not to
spill any and then weighing the remainder and comparing it to the original
weight (similar system to what you suggest). I went the extra mile and then
adjusted the weight by comparing it to oil weight of the same
volume.
I did speak to Richard Sohn at the time but at
that stage he wasn't to concerned with balancing to that extent with his
demonstrator.
It has also been suggested that the apex seal
and springs be excluded as their weight is borne by the rotor
housing.
Then again I've had people argue against those
suggestions.
I thought any out of balance might exacerbate
the negative torque pulses, but your saying because their so large it's
not such a concern - which puts my mind to rest.
I do like your suggestion of 'reverse
engineering' the balancing process, I think I will discuss that with a
professional balancer.
George (down
under)
Lynn,
With balancing my single rotor, what would
you suggest that I allow ( percentage wise) for oil weight in the rotor -
it was suggested to me that I should allow full rotor oil weight.
This discussion suggests otherwise.
George ( down under)
George,
The process I saw
on the internet came from Down there. A rotor is spun up in the lathe with
a plastic shield around the outside. Oil is squirted in until it starts
spilling out. A pan is slipped under the rotor and the lathe stopped. (if
your lathe has a coolant system that would work as well with less mess)
The weights are close enough. Then the rotor is laid on a grill on the pan
and allowed to drain. Then weigh the liquid in the pan. I bet the
balancing people just have a number on the wall for rotaries that is close
to that weight. A balancer could do it backwards by spinning the shaft
from a factory built engine, with the counterweights mounted, and then add
bobweight until he gets a balance. Then subtract the rotor weight from the
bobweight and that difference would be the oil allowance.
The big name
builders all balance to a gnats butt weight, but I just get the rotor
weights the same. Never a problem. The single pulse per revolution will be
so big that a small balance error will go unoticed. But, its no sin to
start out with the balance correct. I have thought about singles and
decided that as big a diameter flywheel that you can fit but weighted only
at the outer edge. Like 4 sets of starter rings tiged to a flex plate.
Even Mazda builds with pieces two weight ranges apart. They have stamped
the weights on rotors, and have used colored paint dots. Of course the
paint dots are gone when we see a used rotor.
Richard Sohn can
tell you. He seems to be doing well with his.
Lynn E.
Hanover
No virus found in this incoming message.
Checked by AVG -
www.avg.com
Version: 8.5.421 / Virus Database: 270.14.5/2419 - Release
Date: 10/07/09 05:18:00