Prop Mounting "Sweet Spot" ???

blimpy

blimpy

New member
Several people including some A&I's have mentioned that there can be a preferred
"sweet spot" ( my phrase) when mounting a propeller, which will tend to minimize or
neutralize vibration.

Nothing in the archives I can find.

Alan who sold me my Cruisair suggested maybe there was a BC Contact article about this ?

All I can think to do is to experiment with prop position, to see if this helps with the vibration
which appeared after the prop was pulled - and the broken nose cowl support bracket was repaired.

Seems unlikely there is any other way.

But what do I know ? :?
 
Some props are keyed using dowel pins, but it has nothing to do with vibration.
Other than those, if everything is right, the prop can be in any position without effecting vibration.
On some aircraft it's beneficial to have the prop in a certain place. 4-cylinder engines with no starter for instance, so it is easier to hand-prop.

If vibration changes with prop position, something is out of balance. Find it and fix it or there will be other problems down the road.
 
I have had my prop "dynamically" balanced( i believe is the term) where they bolt on some vibration detector and index the prop and then run the engine through several rpms to find the vibration so as to be able to find the proper placement for weights to balance the prop to the engine. Anyone know where or who to get this done from?
Phil
 
PhilWebb said:
I have had my prop "dynamically" balanced( i believe is the term) where they bolt on some vibration detector and index the prop and then run the engine through several rpms to find the vibration so as to be able to find the proper placement for weights to balance the prop to the engine. Anyone know where or who to get this done from?
Phil
Click to expand...
Most of the time the guys that do this will come to you. If you're in an area where there's maintenance facilities for prop planes you should be able to Google search one up, or ask around the FBOs.
It's best to assure that the prop is statically balanced first, if you can.

Where are you?
 
Had the aeromatic prop checked, and it was fine with regard to balance and adjustment.

Of course the spinner and it's backing plate are part of the rotating mass that aren't usually part of that
static balance check.

:oops:
 
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