Aircraft Propeller / Engine / Airframe Vibration Reduction — really, really works

Matthew Dock of RPX Technologies recently came to Wichita, KS, to balance the propeller of our Burgundy Demonstrator airplane with the 1/2VW four stroke engine.  I had noticed an annoying little bit of vibration in the instrument panel of the airplane.  The really amazing thing is that after Matthew balanced the engine / propeller, the instrument panel vibration was gone.

I highly recommend his product, the DynaVibe.  I saw how he used it and how quickly it provided a result which made a big difference.

All that was required was mounting a vibration sensor to the engine, along with an optical prop rotation sensor.  After running the engine for a few moments, the DynaVibe provided a vibration reduction solution.

It took a couple of iterations, but we soon had a solution that had substantially reduced the vibration on the propeller / engine, along with my perceived vibration of the instrument panel.

Look at this photo showing the easy attachment of the sensors:

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Two sensors are mounted on the 1/2VW. One provides vibration; the other provides propeller clocking.

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The tape is mounted to the propeller, allowing the vibration sensor to know the clocking of the solution.

Our solution simply involved bolting a couple of washers to the propeller, in the correct location.  (We might have had to use different sized washers to ‘solve’ the problem — but the solution shown worked out great.)  His equipment provided us with guidance as to where to add the weight (by providing degrees from clock center on the propeller).

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The fender washers shown mounted on two bolts were a good solution for vibration reduction on our 1/2VW installation.

Matthew sent me charts of the vibration analysis before and after the improvement.

Here’s the vibration analysis chart before we put the weights on:

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Vibration analysis on 1/2VW engine before improvement.

And here is chart after the weights were added.  Look at how the vibration peaks are reduced!:

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Vibration analysis after adding weights.

There’s a big improvement between these two graphs.  And it was obvious in the cockpit.  My vibration in the instrument panel had disappeared!

Here is the data from the vibration analysis, as the work was done and weights were added:

  • Run 1     0.70@142 [this is vibration intensity @ angle]
  • added 22g at 270
  • Run 2   1.14@244
  • Removed all, added 11g at 270
  • Run 3  0.90@212
  • Removed all, added 11g at 330
  • Run 4  0.57@226
  • Removed all, added 11 at 330, and 11g at 30
  • Run 5  0.04@22

The progressive run data shows how the vibration went down, and was virtually eliminated as Run 5 was concluded.

So cool!!

Matthew’s product is highly recommended.

Contact Matthew for more information  on the DynaVibe; he can be reached at sales@rpxtech.com

Matthew and DynaVibe

Matthew and DynaVibe

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