Dynamic Propeller Balance

You wouldn't think of buying a new set of four-hundred-dollar tires for your car and then pull out of the garage without having them professionally balanced first, would you? All components of an engine assembly, from the crank all the way out to the spinner, are manufactured to strict tolerances, but until the power train and rotating components are balanced dynamically, as an assembly, the job is only half done.

The purpose of dynamic balancing is to minimize vibration levels in the rotating components to a level that will ensure the longevity of the components and a longer service life of the propeller. Increased component life is not limited to just the rotating components. Firewalls, instrumentation, and even aircraft structural members reap the benefits of low vibration levels.

It has long been known in the helicopter world that vibration levels must be minimized for this reason. A helicopter has a rotating airfoil with diameters as large as 50 feet. Such a large rotating mass coupled with the human body's ability to easily sense low frequency vibrations, can make a relatively small amount of vibration feel as though it's going to shake your fillings loose if it's not minimized. The same repercussions occur in fixed-wing aircraft.

A general aviation aircraft is normally flown with the propeller speed of somewhere around 2,300 rpm. This rpm is higher in frequency than that of a helicopter rotor and is not conducted or sensed well by the human body. Normally, by the time the body can start to feel the effect of a vibration at this rpm, the damage has long since started to take its toll on the engine and airframe. The side effects of a high frequency vibration are normally a "buzz" in the pedals or yoke and at times may cause the pilot's feet to fall asleep.

In conclusion, a properly balanced propeller reduces the overall fatigue in the airframe and components. An unacceptable level of vibration affects the entire aircraft in a negative manner. Reducing mass imbalances is the first step to a healthier airframe. But, the implementation of a predictive maintenance program consisting of nothing more than acquiring a vibration signature at specified intervals will reap even greater returns. The cost and labor involved is minimal and the end result is a healthier aircraft.

Give us a call and find out how SMOOTH your aircraft can run!