Did you know that 90% of all the aircraft out there have never had their propellers Dynamically Balanced? When the aft is not in balance with the centrifugal forces of the engine, it causes a lot of stress on the crankshaft, internal engine components (pistons included) and travels all the way through the airframe. It also causes Cabin noise and vibrations that most aircraft owners do not realize are there because they have become accustomed to them and assume that the vibrations and cabin noise are normal. Do yourself, your passengers and your aircraft a favor and have your propeller Dynamically Balanced. You will be surprised how much more comfortable a long flight will be with a smoother running aircraft. You may even see better fuel consumption, better rates of climb and a slightly higher cruise speed. All that energy that is wasted by the propeller not being in balance with the engine can now be harnessed to gain thrust and a smoother, more efficient and quieter running aircraft. 

The cost is only $275 for single reciprocating engine aircraft, $400 for single Turbo Prop and in most cases can be done while you wait. Discounts on twins and multiple aircraft. We can also check the balance of your propeller without balancing it, the cost for this is $175.00  

Our equipment, the Microvib II, made by Dynamic Solutions, also has the capability to comply with the More STC for Pratt & Whitney PT-6 Turbo prop engines. Blue Skies Aviation has the extra equipment and software to place the PT-6 on the More STC and to print the required reports for the More STC. Give us a call or send us an e-mail regarding this service. 

    
What is a dynamic prop balance?

Dynamic Propeller Balancing is the process whereby an electronic balancer is used to measure the vibration produced by the aircraft power plant. Small trim balance weights are added to the propeller/crankshaft assembly to correct for errors in mass  distribution and to reduce power plant vibration due to mass imbalance to the lowest level practical.

How is it done?

The engine/propeller combination is balanced right on the aircraft, in a flight ready state. A small vibration sensor (accelerometer) is attached to the engine in a location where vibration due to mass imbalance is maximum. A small tach pickup (photo-tach) is also mounted to the cowl or engine to produce a propeller  tach signal. The engine is operated and the vibration and tach signals are  processed by the electronic balancer.

The balancer  produces a vibration level (magnitude) which corresponds to the amount of mass imbalance which exists. The balancer also provides a "phase  angle" which corresponds to the location of the mass imbalance  on the propeller disk. The vibration level and phase angle are used to compute a balance solution (weight amount and location). The balance  solution is added to the propeller and the measurement is repeated until the vibration level is found to be acceptable.

My aircraft runs fine. Why should I have my prop dynamically balanced?

By all means, have your propeller balance checked. The average airplane which has not had a Dynamic Prop Balance has a vibration level due to propeller/crankshaft mass imbalance of about .450 inches per second (IN/S) velocity. This level is more than four times higher than what is considered to be an acceptable vibration level for propellers and represents a significantly higher level of wear and fatigue on engine components and accessories (especially the crankshaft, cylinders and yes...even your airframe). This average level is usually very noticeable to the pilot and occupants. Yours may be higher or lower than the average but only a mechanic with a vibration analyzer can tell for sure. On the average, 19 out of 20 fixed-wing aircraft can benefit from Dynamic Prop Balancing yet many will never have it done.

My engine and prop were overhauled recently. Should I have my prop dynamically balanced?

Both new and used components need to be dynamically balanced. In fact, the best time to dynamically balance a propeller/engine combination is right after overhaul when components are fresh. No appreciable difference was found between the vibration levels of recently overhauled and longer time propeller/engine combinations. Even brand-new aircraft with zero time engines and propellers need to be dynamically balanced.

What level of propeller vibration is acceptable?

In most cases, the vibration level due to mass imbalance can be brought down to under .100 IN/S very easily. The average level seen post-propeller balance was .039 IN/S. When propeller vibration levels are this low, the operator will generally see a significant reduction in component wear and fatigue and will find that the aircraft "feels" like a completely different machine.

In addition to that the mechanic now knows what all of the other engine vibration levels are (Prop/crankshaft mass imbalance usually dominates them) and can utilize that information if additional work is needed.

But won't having my propeller dynamically balanced "mask" other engine problems?

No! An engine with an internal problem which results in unusual vibration will not  respond to balancing in the same way that an engine which only suffers from mass imbalance will. A qualified mechanic will use ALL of the information available to make a judgment about your engine, including the vibration response.

Digital or Analog?

We are the only operation in central Texas that has digital balancing equipment. Analog balancing systems can not balance propellers to the same degree of accuracy that our digital equipment  can. Our Microvib system can get most props balanced to within 0.001 degree of center, generally analog systems can only balance props to within 0.01 degree of center. This might seem like a minor, but it translates into a lot of felt vibration, noise and stress on crankshaft and airframe and that's thousands of dollars saved in maintenance expense.