Stillwater Aircraft Services recently began using a DynaVibe GX2 to provide dynamic propeller balancing and vibration survey services. Brian Smith, owner of this service center, is using DynaVibe to bring new work in while serving his existing clients better.
One of Brian’s initial successes with DynaVibe came with a client who flies a Beechcraft Super Musketeer with a 200 horsepower engine and a constant speed prop. This airplane had a known vibration problem, but it had never been addressed. The propeller was last statically balanced in 2000.
The initial propeller-balancing run revealed a severe vibration of 1.5 Inches Per Second (IPS). This was well above the FAA specified maximum limit for propeller vibration of 1.2 IPS which requires that the prop be removed and statically balanced prior to dynamic balancing on the aircraft. Even following standard dynamic balancing procedures, Brian could at best reduce the vibration by about half. It was much better than the starting level of vibration, but still severely out of balance. Brian pulled the prop off the airplane and took it to a prop shop to have it inspected, where he was surprised to learn that during the last static balancing 15 years ago, the weight had been added to the wrong blade.
“When they put the prop on the balancing stand, one blade immediately fell to the floor,” said Smith. It’s unfortunate, but once in a great while, the weights are applied to the wrong blade in the static balancing process, and that was the reason this Musketeer had experienced a vibration problem for 15 years.
After having the prop statically balanced, Brian remounted it on the Musketeer and checked the balance again using his DynaVibe system. The static balancing had reduced the prop vibration to about .67 IPS. Brian used the automatic weight solution calculated by the DynaVibe GX2 and almost completely eliminated the vibration, getting it down to .04 IPS. The owner’s feedback was that his Musketeer felt like a totally new airplane!
Brian sees multiple benefits to offering dynamic prop balancing services with DynaVibe. “It will help pull more business in, I’ll get more work off of it, but the customer gets something too – a measurable difference in the performance of their airplane.” In addition to propeller balancing, Brian sees the advantage of the vibration survey capability that the DynaVibe GX2 provides: the ability to identify the type and source of a more complex vibration. “I can see a half-per vibration using the DynaVibe, and know that it’s caused by a combustion problem. That information eliminates other vibration sources and narrows it down to the specific problem I need to address. That’s a home run. When servicing an airplane, I don’t need to go down as many rabbit trails.”