Dynamic prop balance

bernsbm · #1 06-07-2017, 01:56 PM

Hi All,
I'm looking for a shop in the southeast Wisconsin/northern Illinois area that can do quality dynamic prop balancing, preferably with Rotax experience. Any/all suggestions appreciated.
Barry

springer · #2 06-07-2017, 04:36 PM

Quote:

Originally Posted by bernsbm

Hi All,
I'm looking for a shop in the southeast Wisconsin/northern Illinois area that can do quality dynamic prop balancing, preferably with Rotax experience. Any/all suggestions appreciated.
Barry

Not SE WI but at the Cumberland Airport, WI the Cirrus dealer does it. I have not used them.

http://www.aviationvibes.com/vibrati...nd-mitigation/

Piper J3 · #3 06-07-2017, 08:15 PM

I'm curious... why do you feel the need to balance your prop? I set the pitch on my blades with Van's sheetmetal gage and I'm very pleased with the flight performance and engine/prop smoothness especially at cruise RPM.

Walt · #4 06-07-2017, 08:24 PM

I have balanced quite a few 12's and every one benefited significantly. It is also a recommended procedure by both Rotax and Sensenich.

12vaitor · #5 06-07-2017, 10:59 PM

Just finished balancing mine this weekend. Started out at 0.21 ips, was very happy with the final result after adding 11 grams of weight.

John Salak
RV-12 N896HS

Slane · #6 06-07-2017, 11:07 PM

Where and how did you attach the weight?

Driftdown · #7 06-07-2017, 11:17 PM

Quote:

Originally Posted by Slane

Where and how did you attach the weight?

x2 . . . . . .

Mark C. · #8 06-07-2017, 11:45 PM

Call Poplar Grove Airport, IL they have a guy that balances props. About $250. Mark C.

12vaitor · #9 06-08-2017, 01:15 PM

Quote:

Originally Posted by Slane

Where and how did you attach the weight?

I started out by adding weights (washers) under the spinner attachment screws at the clocking angle indicated by the DynaVibe display. Took four runs to get the ips down to 0.01-0.02. I used a precision scale to weigh the washers and converted the inch/gram value based on the spinner screw hole location to the spinner plate location I drilled (radius decrease by 1/2" so weight value increased). I added a #8 screw with two nuts and a spacer weight at the new hole in the spinner backing plate. The total weight of the screw, nuts, washers, and spacer weight were 11g. I was fortunate that the clocking angle was almost exactly on a spinner attachment screw.

The factory listed weight difference between the two Sensenich blades is 6 grams (1204g and 1198g), so the weight location is actually near the root of the lighter blade. Not sure how that compares with other RV-12s, but it may be an indicator of the improvement you can expect from dynamic balancing.

John Salak
RV-12 N896HS

dtw_rv6 · #10 08-06-2017, 06:48 PM

I spent Saturday morning trying to balance my RV6 / Superior IO360 / Sensinich setup with the same Dynavibe model shown in the photo above. However after 8 runs trying to dial in on the best balance, I discovered that none of the results were repeatable on subsequent runs! I removed all weights and headed home to ponder what could be going on.

Has anyone else found repeatability to be a problem? I was able to get down to about 0.12ips, but a 2nd trial with no change yielded 0.38ips!

Originally my setup was showing 0.42ips. The last run of the day was back to no weights, and I was getting 0.57ips. Not sure what is going on. We had similar results on a different engine and airframe earlier that week.

Don