On Sun, 28 Nov 2004 03:36:25 GMT, Chuck wrote:

Below, interspersed

Hi guys & gals,

I purchased an older Cherokee 180 with a Lycoming O-360A4A and
Sensitech propeller. Unfortunately, I'm not sure on of the prop model
as I haven't pulled the cone yet.

It's either a 76EM8 or a 76EM8S5

Since I purchased my Cherokee, there has been a slight vibration in it
while running and flying. The first mechanic I had went for a ride
with me and immediately said the prop needed a "balance" job.

But since then, another very experienced A&P has told me that
fixed-pitch props are never "balanced". This guy told me that balance
jobs are done on constant-speed props and not fixed-pitch.

So, does anyone have experience with a balance job on a fixed-pitch
prop? Or has anyone had a vibration problem that turned out to be a
fixed-pitch prop balance problem???

I've balanced quite a few of them. Honestly, if you have a vibration
problem, you should probably have the propeller removed and inspected
for condition/static balance by a prop shop.

I really don't want to be the one to tell you this, but anyone
purchasing any aircraft with this engine/prop combination should have
the prop inspected as part of the pre-buy inspection.

This engine/prop installation has zero tolerance for diameter
reduction. Unfortunately, it is quite common for the tips to be
re-worked and re-painted, if the prop has been "shortened" at all, it
is no longer airworthy.

I ask because it would take a week to get the equipment in and of
course, cost several hundred for the prop balance. I'd hate to spend
that money and still have the vibration problem.

When I was in the dy-bal business, we often charged a reduced rate if
no "balancing" was needed. Can't you find someone in your area that
performs dy-bals on a regular basis?

TC

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