---------------------------------------------------------- RV4-List Digest Archive --- Total Messages Posted Sat 07/26/03: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 10:35 AM - Re: Fixed Prop Balancing (Andy Hawes) ________________________________ Message 1 _____________________________________ Time: 10:35:58 AM PST US From: "Andy Hawes" Subject: Re: RV4-List: Fixed Prop Balancing --> RV4-List message posted by: "Andy Hawes" Hello Gene, I have a Pitts S-1S that I will probably have "dynamically balanced" in a few weeks for a couple hundered. I know very little about this but from a quick explanation from my hangar mate, Steve Johnson (S2B Advanced Acro guy), he tells me that the airplane is tied down (very strong cable from a fixed anchor to the tailwheel), the engine runup to 2500 RPM for 30 seconds. Sensors are mounted to the airframe, engine mount, engine, etc. looking for some sort of measurment of vibration. There is a range, and they will apply weights to the spinner until the range is at the lower level. You can then come back, remove the spinner, and move the weights to the inside re: aesthetics. Yes, a very crude definition, so you might want to ask some of the pros around here. The ultimate point here being that it might not be just your prop, but perhaps a combination of all that is capable of producing vibrations on your plane. Steve swears by it and has had all his planes done up this way -- very smooth ride in the long run, along with less wear and tear. Hope this helps, Andy Hawes Pitts S1S, Nashville EAA 710092 ----- Original Message ----- From: "Gene Smith" Subject: RV4-List: Fixed Prop Balancing > --> RV4-List message posted by: "Gene Smith" > > Educate me someone.........Getting some increased vibration on my RV-4, and I am concerned......This is a Sensenich fixed with no damage or strikes, and hasn't been re-pitched or worked on since new...... Not even a rock pock mark......Bolts are tight and torqued......It is installed on a Lycoming 160 HP engine with about 400 hours on the prop, and 1300 hours on the engine. > > If I hire "prop men" to come out and check it, what is their procedure?......Do they balance it on the aircraft with the engine running?......Pull it and rotate it on some machine like for auto wheels?......How do they check the crankshaft to see if it is the problem?......Do they install weights, and if so, how and where do they mount them? > > Would appreciate any info from you folks that have experience in this area..........................CHEERS!!!!.................................Gen e Smith. > >