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Hello All, I have been in the background studying for my build
project. Grayhawk, your information about the harmonic damper is an
educational point of significance. I know nothing about dampers, is
there a book that I can get to learn about this subject. Does a
damper have to be specific to an engine or is the design universal
to any recip?
Thank you for any advice in advance,
Sincerely,
Mr. Slava Harlamor
--- On Mon, 2/21/11, Sky2high@aol.com
<Sky2high@aol.com> wrote:
From: Sky2high@aol.com
<Sky2high@aol.com>
Subject: [LML] Re: prop
balance
To: lml@lancaironline.net
Date: Monday, February 21,
2011, 10:32 AM
Jack,
The 12 pound harmonic damper is present to reduce
negative torque between power strokes. It has a steel ring
suspended in silicone. It does not help balance the
prop - it should be totally neutral with respect to balance but
not circular momentum. On fixed-pitch prop (likely wooden or
composite) driven engines, there is often a 100 rpm increase
because of added momentum and a reduction in the negative torque
by damping it. Constant speed prop users may find it
difficult to measure the effect. Another benefit is to move
the CG forward - usually a plus in the 320/360 series
aircraft.
The person in Redmond is wrong. He is misinformed about
the purpose of the damper.
I have such a damper and I do balance my prop. Because
I am in a partnership that owns a simple balance
device, I have no constraint on performing a balance or just
checking the last balance to insure it has not changed (it has
not).
Go balance that prop. Weights/longer bolts can be
affixed where the damper is mounted to the starter ring.
However, be careful that any large area washers not
stick out far enough to come in contact with the cowling in
dramatic + or - G maneuvers.
Geeeeze!
Grayhawk
In a message dated 2/21/2011 7:26:04 A.M. Central Standard
Time, jraddison@msn.com writes:
Question?
On my LNC2-360 (BIB plus high comp
pistons) there is an add-on "balancer" bolted to the face of the
starter ring gear.
It is supposed to balance the engine with
its internal weights that are supposed to arrange themselves to
cancel or dampen our any sensed vibrations.
The "balancer" is
about 2 inches in debth and almost the diameter of the ring
gear; it is all self contained and you would have to take the
prop off to get it off and take it apart if one was at least
currious what was inside of it.
It's difficult to
know if a 4 cyclynder Lycoming is as smooth as it can be,
because it's not a real smooth engine under the best of
conditions.
I inquired to a local experienced prop
balance person in Redmond and they concluded that because of the
dynamic balancer on the ring gear, he would not attempt to
balance the engine with his expensive balance work, as he
thought the attached dynamic balancer would change the internal
weight at will.
Does anyone have any experience
with these dynamic balancers attached to the ring
gear???
Cheers
Jack Addison
N360JS
near Redmond,
OR
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