Wierd vibration -- Prop or engine, balance or not???

Hi Chuck

I suggest that the first thing you do is check alignment/tracking.
Why? Because it takes one minute and costs nothing, and if nothing else
it eliminates a probable cause.

So. Get yourself a cardboard box, and stand it on something that allows
the prop to touch the box.

Place the box so it is exactly touching the prop.
Rotate to the other blade.
Does that also touch the same?
If it does then it ain't tracking.
If it doesn't - get that checked first.

HTH

Tony

In article ,
Chuck wrote:

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.

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 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.

Thanks for any suggestions or information you guys can offer.



Chuck
N7398W




--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE