Dynamic Prop Balancing?

Huckster79

Huckster79

Pattern Altitude
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Huckster79
any first hand stories? Good or bad... I’m thinking about it, concept makes sense... Those that have done it, was it a noticeable difference without a measuring gadget?
 
I used to fly a Cessna AgTruck, it broke alternator brackets on an almost regular basis, a Dymanic balance was done and there were no more problems
 
The club has had the props balanced on both our aircraft (Bo V35 and C182P). Very noticeable reduction of noise and vibrations felt. Cost was very small in the scheme of aviation maintenance things.

@Jay Honeck had it done several years ago to his RV8 and did a write up.... I recall he experienced a significant night and day improvement.
 
First hand from the last couple weeks.

Yes, noticed a difference during the test. But we did not keep the weights on because it was more than what was the recommended weight limit for the spinner bulkhead.

My A&P ran the test again the following week, under a few different conditions under advice from a respected prop shop. Still no bueno.

I cut open the oil filter just to be safe. Looked good. Doesn’t mean it’s not a valve, ignition, or fuel issue though.

Going to fly it to the prop shop to have them figure it out.

Did I feel what 0.06 ips felt like? Absolutely. Very smooth. So I was not imagining the rough/vibration (I was starting to second guess myself).

Another piece of advise given to me by one 70+ and one 90 year old pilot: if it ain’t broke, don’t try to fix it, and leave well enough alone.

Ima fix this tho. Ain’t right.
 
Last edited:
Huckster79 said:
Those that have done it, was it a noticeable difference without a measuring gadget?
Click to expand...
In some cases it can be a felt difference. But keeping the engine/prop in balance helps reduce the fatigue on the mounts, exhaust systems, and other items susceptible to excessive vibrations. It was the one thing I always recommended to clients whether I performed the balance or not.
 
Helps to start out with the prop off and a static balance by a prop shop. No sense dynamically balancing a prop that doesn't balance in the shop.
 
Noticeable drop in vibration when I did mine last year. Very worth it.
 
Been doing it to all the planes I've owned. Sometimes it's very noticeable, sometimes just a tad. One plane's AP started flying better. AI and DG were not getting all rattled about. They did get replaced, and saved us a few AMUs thinking we need a new AP.

My IA told me a story. The prop and engine were balancing fine, but there was a strange harmonic they couldn't dampen, and the curtain rods still vibed like a base guitar string. They took the odd harmonic and divided by 6 or 3 or whatever, and figured out a magneto was making the odd vibes. New mags and the old 6 banger was jet smooth!
 
Just had both sides done on the Aztec a few weeks ago. The smoother things are the less stress on everything else (airframe, avionics, etc.) and less fatigue for me on longer flights.
 
Well that seals my decision! Yea there’s a shop close that does it for 1/4 of an AMU, and only 0.2 AMU if you bring three planes to do at once! I think I’ll chat w the pilot breakfast gang and see if a couple others wanna go for it too...
 
Many aircraft/props/ engines have a particular position for the prop to be mounted.
be certain the prop is in the correct position prior to balancing it.
 
Tom-D said:
Many aircraft/props/ engines have a particular position for the prop to be mounted.
be certain the prop is in the correct position prior to balancing it.
Click to expand...

:yeahthat:

Twice I have had props installed that were not properly indexed.

Also, make sure your mags are in good shape and accurately timed, your spark plugs are clean and all are firing properly, there are no issues with the ignition harnesses and the engine isolators (Lord mounts) are in good shape (not hard, cracked and sagging). Before the dynamic balance.
 
I had the Chadwick Helmuth Vibrex 2000 at the flight school, and did all the airplanes with it. Even when there was no improvement noticable to the pilot, the gyros and radios felt the improvement and gave a lot less trouble.

The propellers were overhauled at engine TBO and the mags got the 500-hour internal inspections and repairs. Sparkplugs were tested every 100 hours and any that showed spark blowout at 135 psi were replaced. The engine mounts were replaced every engine change, which was usually no more than three years apart. The prop balance just cleaned up whatever shake left over, which was what the instruments and avionics were feeling.
 
Tom-D said:
Many aircraft/props/ engines have a particular position for the prop to be mounted.
be certain the prop is in the correct position prior to balancing it.
Click to expand...

Checked, that’s correct. One of the guys on the 140 forum said he has turned the position 180 and got improvement sometimes...
 
I got another guy that wants to do it... one more and I’m down to 0.2 AMUs!
 
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