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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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