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Re: [FlyRotary] Rotating Assy Stuff was Re: [FlyRotary] dy
Howdy Ken,
Yes, we have a mandrel for the rotors
themselves, and mandrels for the lightened, as well as stock
manual flywheels. This is used when swapping a manual flywheel for an
auto counterweight and a lightened flywheel.
Of course, my Balancier does a wide variety
of piston engines as well and he has literally a wall full of different mandrels
to hold various flywheels etc from piston engine cars as well as
rotaries.
So the procedure is to find the lightest
rotor, and then dynamically balance that on the rotor mandrel.
Obviously, the balancing procedure of removing metal from the rotor
lightens it even more. The second (and 3rd if a 20B) are then dynamically
balanced out until they weigh the same as the first rotor.
As you saw from one of the pix I posted, I
had 2 12A rotors that were EXACTLY the same weight. You will note the ball
bearings held with "Blue Tack" to make allowance for the oil. With the
later model shafts, we normally just put a carefully calibrated brass
weight into the rotor lobe hole(s), and then adjust where necessary
with ball bearings and "Blue Tack".
The extra weight is to allow for the mass of
oil that has been determined by trial and error over the years. It does
vary a bit from rotor model to rotor model as the internal volume of the earlier
rotors are less than the later models due to the thinner wall castings.
Obviously 10A and 12A rotors have smaller internal capacity than any of the 13B
rotors. So it's a bit of a "Black Art".
The rotors are then put on the shaft and the
whole assy is then spun up and the counterweights are adjusted until the whole
assy balances out nicely. Using the rotors themselves is easier than
fiddling with a collar and removable masses like they do on V8s etc. Has
to be done on a piston engine crank, but using the rotors themselves
workds just dandy on rotaries.
Cheers,
Leon
----- Original Message -----
Sent: Thursday, January 13, 2005 4:45
AM
Subject: [FlyRotary] Re: Rotating Assy
Stuff was Re: [FlyRotary] dynamic balancing
Hey Leon
You talk about mandrels, are the mandrels for
balancing the rotors first??
I assume that you balance the rotors first and
then put the on the e-shaft and balance the assembly.
Ken
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