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Hey Marv,
I would assume that nearly every MAzda specialty shop in the USSA would have
a balancing service. Anybody that races, and light-weight rotors MUST
rebalance their engines. (Otherwise, the engines will rattle the fillings
out of your teeth).
All it requires is somebody to get on the Al Capone and talk to the various
shops. Mazdatrix, and Pineapple Racing among others come to mind. Bruce
should know, and I would assume he would have his favourite Balancier too.
Balancing is a pretty straight forward procedure.
1. Weigh rotors and find the lightest.
2. Dynamically balance that one.
3. Dynamically balance the other one(s) until they all weight the same.
4. Balance the rotating Assy as a unit.
This can be done by putting the rotors on the shaft with all the seals
(EXCEPT the apex seals), or having special weights that clamp on the shaft
(just like they do with piston engines).
Here is the "Black Art" part of the procedure. The rotor is filled with oil
when it is operating. An allowance for that mass of oil (or a certain
percentage of the mass of that oil) has to be made. Think about a bucket of
water on a rope that you are swinging around. What %age? Trade Secret.
You know you have got it right when the motor is DEAD smooth. (Big cheesy,
leery eyed grin!!).
In the pix attached insubsequent emails, you will see a pair of 12A rotors
progressively being done. In pic 2, you will see the ball bearings held in
with "Blue Tack", to compensate for the oil mass. In another pic, you
will see water/soluable oil being used to estimate rotor internal volume.
Just weigh the bottle before and after. Voila! That's how many grams you
need to allow (or a %age thereof).
Cheers,
Leon
----- Original Message -----
From: "Marvin Kaye" <marv@lancaironline.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, January 12, 2005 1:31 AM
Subject: [FlyRotary] dynamic balancing
>
> Lots of great discussion here the past several weeks (actually, the past
> several years have been excellent) and the topic of dynamic balancing of
the
> spinning parts has been talked about quite a bit. No one, though, has
> mentioned where you send the rotating assembly to get it balanced and what
it
> costs. Does anyone who's been down the path have a list of sources for
> balancing and an idea of the cost involved? I assume that when the
assembly
> gets sent out it includes the rotors, e-shaft, & both counterweights...
what
> about the flywheel? Is that (or should it be) included in the stuff
provided
> for the dynamic balance? Am I missing anything?
>
> <Marv>
>
> >> Homepage: http://www.flyrotary.com/
> >> Archive: http://lancaironline.net/lists/flyrotary/List.html
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