Dynamic Propeller Balancing

This past Sunday we flew down to KFFC (Peachtree City, GA) for the Falcon RV Squadron St. Patrick's Day potluck and to get our prop balanced. The potluck was amazing, as usual, and the prop balancing was neat to learn and take part in.

First we removed the top of the cowling and bolted a small sensor to the engine. He then put a piece of reflector tape on the prop to mark 0 degrees. 

 

We ran the sensor cables down the wing and connected them to the handheld receiver. Then, Brian got in the plane and ran it up to about 2400 RPM. Once the RPM was stable, Brian gave the thumbs up and we grabbed a reading from the receiver. It took all of 5 seconds to get a reading. 

At the first reading, our prop came in with a vibration level due to mass imbalance of 0.25 IPS (inches per second) (low end of rough) @ 111 degrees. We drilled a hole in the back plate of the spinner and installed a bolt with some washers @ 291 degrees. After putting the spinner back on, Brian got back in the plane and we recorded our second reading. The second reading was much better: 0.07 IPS (good) @ 219 degrees. We could chase this all day but we decided to stop here. Tommy, the expert prop balancer at KFFC, told us that any change under 0.10 IPS wasn't noticeable.

After the potluck, we got in the plane and headed home. At this point, we had both almost forgot about the prop balancing. At least, until we took off. Oh boy! What a difference!! I didn't think our plane was THAT rough to begin with but I felt the difference before we were 1000 feet off the ground. A few seconds later, Brian looked at me and we both just smiled. We knew the flight home was going to be the best one yet! =D

This plane is so amazing... and so are the views!

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