Prop Balancing 101 – The hows and whys explained

Prop Balancing 101

Can you feel a vibration in your aircraft while flying? Maybe it is so very slight, hardly noticeable. In fact, you may have even gotten used to it as just being ‘one of those things’.

Many times the root cause of the vibration is coming from the propeller being off balance. Having a properly balanced prop will not only improve engine performance and fuel economy, but it will also prevent engine and airframe damage over time. 

Picture a ceiling fan spinning slowly and swaying back and forth. The reason for this sway is due to one blade being heavier than the others. Increase the fan speed and the swaying will turn into vibration.

In your plane this imbalance can cause premature prop shaft bearing wear, crankshaft problems, and place unnecessary stress on the air-frame causing cracks and loosening hardware. Let’s not forget about added fuel costs due to this inefficient prop to engine relationship.

A new or overhauled propeller will be static balanced by the propeller shop just to make sure each blade weighs the same. But once installed on the aircraft, the propeller needs to be paired to the engine for proper balance during operation.

Dynamically balancing the propeller to the engine while its at cruise RPM will ensure a correctly balanced and vibration free setup. Any imbalance between the engine and the propeller will be corrected during this process.

Prop Balancing

How do propellers get ‘out of balance’ in the first place?

Propellers can be out of of balance for any number of reasons:

  • Debris strikes to the blades will require filing to smooth them out. This process ever so slightly removes material which can cause an imbalance.
  • Crankshaft counterweights can wear as the engine hours increase. Any imbalance in the spinning crankshaft will only be amplified at the propeller.
  • Or perhaps the propeller was never set up correctly when installed as new or after re-installation following a propeller overhaul.

A prop balancing service will level the weight of each blade and remove that unnecessary vibration improving engine performance, fuel economy, and extending the life of your machine.

Have questions? Call Sky Manor Air Repair at 908-996-0541 and speak to one of our IAs. We would be happy to help you out.

Sky Manor Air Repair and Avionics
48 Sky Manor Road
Pittstown, NJ 08867