I always try to do things as well as I can for my RV-6A and after fretting over dynamic balancing for some time I finally had my prop balanced at Hartzell Field this morning by the company service personnel. They were very polite and accommodating and yesterday they provided hangar space a plant tour and gave us two company hats.
The process involved running up the engine, cycling the prop, increasing the rpm to 2550 then reducing it to 2450, signaling the operator to take a reading. After this the operator added washers to the spinner and the process was repeated. The operator did some more work (I assume weight adjustment) and the process was repeated again. Then the spinner was removed and a hole drilled in the spinner backplate at a location indicated by a computer and a standard weight was added. I was told the the displacement before the balance process was approximately 1/4" and the weights added during the three cycle process was some much smaller number.
I asked don't you want to run it again and I was told no it isn't necessary.
When I started the engine to leave it did seem smoother and I broadcast that to them on 123.0. Later in flight I really could not tell any difference from the operation/vibration/noise/visual observations before the dynamic balance procedure.
The process was cheap $269.50 and it was quick (minutes not hours). From many years of testing in aerospace I cannot accept the fact that it is acceptable to apply weight to determine what is needed in one place then use a computer to mathematically determine where to install a different weight to have the same effect then do that and call it done with no post installation verification. My belief that Hartzell does it better than anyone else is not verified. If you are contemplating this performance mprovement you should be aware of how it is done at this facility and consider whether it is worth making a trip to Piqua, Ohio to have it done.
Bob Axsom
The process involved running up the engine, cycling the prop, increasing the rpm to 2550 then reducing it to 2450, signaling the operator to take a reading. After this the operator added washers to the spinner and the process was repeated. The operator did some more work (I assume weight adjustment) and the process was repeated again. Then the spinner was removed and a hole drilled in the spinner backplate at a location indicated by a computer and a standard weight was added. I was told the the displacement before the balance process was approximately 1/4" and the weights added during the three cycle process was some much smaller number.
I asked don't you want to run it again and I was told no it isn't necessary.
When I started the engine to leave it did seem smoother and I broadcast that to them on 123.0. Later in flight I really could not tell any difference from the operation/vibration/noise/visual observations before the dynamic balance procedure.
The process was cheap $269.50 and it was quick (minutes not hours). From many years of testing in aerospace I cannot accept the fact that it is acceptable to apply weight to determine what is needed in one place then use a computer to mathematically determine where to install a different weight to have the same effect then do that and call it done with no post installation verification. My belief that Hartzell does it better than anyone else is not verified. If you are contemplating this performance mprovement you should be aware of how it is done at this facility and consider whether it is worth making a trip to Piqua, Ohio to have it done.
Bob Axsom