Re- Prop' Dampener

Rick Harper · Post by **Rick Harper** » Fri Feb 17, 2012 8:47 pm

G'day everyone !

I was told some time back that "you only NEED a (Mark Landoll's) vibration dampener
if you ARE USING a wooden propeller" !?!?!

Can SOMEONE post a few pictures of one of these suckers in the archives...there's NO way
I can afford to shell out $400 U.S. with the exchange rate at 52 cents to the US dollar...
If I can get a look at one, I reckon I can make one....I hope.

How come this problem has only come to light NOW ????? I'm sure that there are HEAPS
of Rebels out there who have been using a W.D. Prop with a Lycoming engine for years !

Rick & Wendy Harper

apat · Post by **apat** » Fri Feb 17, 2012 8:47 pm

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To: <murphy-rebel@dcsol.com>
From: Bob Patterson <apat@istar.ca>
Subject: Re: Re- Prop' Dampener

Hi Rick !

There <are> lots of Rebels flying with 150 HP O-320's, and it's
taken about 4 years and 600 - 800 hours to show the problem ....

But the higher compression engines, like the 160 HP O-320's,
and the Continental IO-240's get problems VERY quickly - like under
50 hours !! It seems the higher compression causes sharp power
pulses that 'wiggle' the blades fore & aft, and they crack.
All the damper does is absorb some of the pulse internally, through
rubber bushings around the bolts, and partly just because it adds
some extra mass .... The much larger mass of the metal props
gives a flywheel effect, and absorbs these pulses, so there seem
to be no problems with them. (Of course, metal prop manufacturers
DO spend many $$$$$ 'tuning' their props to avoid harmonic vibration
problems .... which is another reason metal props cost lots
of $$$$$ ..... :-( )

I'll bet you could find a very similar setup in a motorcycle
clutch, or even an automotive clutch system.... Just turn down
the plate with the bushed bolts ...

.....bobp

-------------------------------orig.--------------------------------------
At 11:02 PM 3/3/01 +1100, you wrote:

G'day everyone !

I was told some time back that "you only NEED a (Mark Landoll's) vibration

dampener

if you ARE USING a wooden propeller" !?!?!

Can SOMEONE post a few pictures of one of these suckers in the

archives...there's NO way

I can afford to shell out $400 U.S. with the exchange rate at 52 cents to

the US dollar...

If I can get a look at one, I reckon I can make one....I hope.

How come this problem has only come to light NOW ????? I'm sure that there

are HEAPS

of Rebels out there who have been using a W.D. Prop with a Lycoming engine

for years !

Rick & Wendy Harper
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<STYLE></STYLE>
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<BODY bgColor=#ffffff>
<DIV><FONT size=2><EM>G'day everyone !</EM></FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=2><EM>I was told some time back that "you only NEED a (Mark
Landoll's) vibration dampener</EM></FONT></DIV>
<DIV><FONT size=2><EM>if you ARE USING a wooden propeller" 
!?!?!</EM></FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=2><EM>Can SOMEONE post a few pictures of one of these

suckers in

the archives...there's NO way</EM></FONT></DIV>
<DIV><FONT size=2><EM>I can afford to shell out $400 U.S. with the exchange

rate

at 52 cents to the US dollar...</EM></FONT></DIV>
<DIV><FONT size=2><EM>If I can get a look at one, I reckon I can make
one....I hope.</EM></FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=2><EM>How come this problem has only come to light NOW
?????  I'm sure that there are HEAPS</EM></FONT></DIV>
<DIV><FONT size=2><EM>of Rebels out there who have been using a W.D. Prop

with a

Lycoming engine for years !</EM></FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=2><EM>Rick & Wendy Harper</EM></FONT></DIV></BODY></HTML>

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Legeorgen · Post by **Legeorgen** » Fri Feb 17, 2012 8:47 pm

Rick and Wendy,

I don't thing you will be able to make a vibration dampener even if you had
one to take apart. I don't believe it is absolutely necessary to have one
with a WD prop, just more insurance against a possible delimitation or
cracked hub.

Bruce G

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