DynaVibe Blog

LOBO puts DynaVibe in Engine Test Kits

Thursday, March 31, 2016

Bob Pastusek is vice-president and a board member of the Lancair Owners & Builders Organization – LOBO – and is their go-to maintenance guy.  A few years ago, the LOBO Board became concerned that people were not tuning up their airplanes properly; they were not following all the recommended engine and airplane manufacturer’s guidelines in doing their condition inspections.  “Experimental owners are not obliged to follow them,” said Pastusek.  “Nonetheless, like putting air in your tires or oil in your engine, some recommendations are more significant than others.  We came to the conclusion that some people were not doing some of the important ones, based on accidents and probable cause findings that indicated maintenance wasn’t as good on these airplanes as it could be.”

In December 2014, LOBO put together a kit of materials for testing and inspecting the engines, specifically Continental aircraft engines.  “This worked out really well for us,” Pastusek continued.  “So at the fall LOBO fly-in, we asked what people (members) thought about it, and the feedback expressed a desire to include some additional equipment in the kit. One of the principal requested pieces of equipment was a prop balancer.” 

Pastusek first learned about the DynaVibe propeller balancing system at Oshkosh four or five years ago.  He bought one for his local EAA chapter and has used it several times to help chapter members balance their props.  “Having personal experience with DynaVibe, knowing that it works and that it is a reasonably priced piece of gear that our average homebuilder could figure out how to use, we bought new DynaVibe systems to include in our three engine inspection and tune-up kits.

Pastusek recognizes the importance of keeping the prop in balance.  “It makes the airplane engine run smoother, with less wear-and-tear on the engine.  The aircraft is much more pleasant to fly.”  In general, Lancairs use factory-balanced, high-end adjustable pitch props.  “They come pretty well balanced; we generally don’t have an issue with props significantly out-of-balance.  However, there are a couple of things that homebuilders can do, particularly in mounting the spinners and things like that, that can cause them to be out of balance.  It’s a very easy thing to check and improve.  If you find the prop out of balance and fix it, it really makes the airplane run a lot smoother.  These are very large engines in relatively small and lightweight aircraft, so a prop imbalance will shake the airplane around pretty well.”

The LOBO engine test kit with the DynaVibe prop balancing system is expected to be available to members in April 2016.  “We think the DynaVibe is a relatively sophisticated but easy tool to use in the field,” Pastusek concluded.  “It works like a champ.”  

The affordable DynaVibe Classic propeller balancing system is just $1,495 shop for it the DynaVibe online store.  If you'd like to know more about DynaVibe, please contact us at 650.800.3092, sales@rpxtech.com, or simply enter your email address in the form below and we'll contact you!

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Why Statically Balanced Props Still Need Dynamic Balancing

Monday, March 14, 2016

A balanced propeller assembly is important not just for having a smooth flying experience, but also for the health and longevity of an airplane’s engine, instruments and airframe.  Statically balancing a propeller can help reduce vibrations, but to reduce prop imbalance-induced vibration to the minimum, dynamic balancing is recommended. 

This story of a Beechcraft Super Musketeer illustrates the importance of dynamic prop balancing, even after static balancing has been performed.  This Beech had a 200 horsepower Lycoming engine and a constant speed prop.  The airplane had long experienced a vibration problem, but the owner had never attempted to resolve it.  The airplane’s propeller was last statically balanced in 2000.

Even though a prop has been statically balanced, once mounted, things can change because the entire propeller assembly comes into play, not just the perfectly balanced, ready-to-mount prop.  

It takes just the slightest change in mass anywhere in the propeller assembly to change the balance and introduce a vibration.  These numbers illustrate this reality:  a perfectly balanced prop, offset by just .0005 inches during installation, can cause a vibration of .6 Inches per Second (IPS)!  This scenario occurs more often than most pilots or owners know, because many props don’t have an indexing mechanism to ensure that during mounting, the prop it is perfectly centered with the crankshaft.  The dynamic balancing process corrects these “coupling” errors that can result when mounting a prop.

In the case of the Super Musketeer, the prop imbalance was discovered when the owner brought it in for some maintenance.  The mechanic had access to a DynaVibe balancing system and did a quick prop balance check.  This check revealed a severe vibration of 1.5 IPS, well above the FAA specified maximum limit of 1.2 IPS for prop vibration.  A vibration of this magnitude mandates removal of the prop for static balancing.  The mechanic pulled the prop off and sent it to a prop shop for inspection and static balancing.  The mechanic and owner were surprised to discover that during the previous static balance from 15 years ago, the weight had been added to the wrong prop blade, making the balance and vibration problem worse, not better.  The owner had lived with this problem, simply assuming that some level of vibration is a product of combustion. 

After the static balancing was complete, the mechanic remounted the prop on the Super Musketeer and dynamically checked the balance.  The static balancing process had reduced the prop vibration by about half, to .67 IPS.  Using the weight solution provided during the initial dynamic balancing check, the mechanic added the prescribed weight where indicated and did a second balancing run, which showed the vibration had dropped to .04 IPS, well below the level that is discernible by the pilot or passengers.  The following report was generated by the DynaVibe GX2 and shows the results of the dynamic balancing runs, including the level of vibration detected and the weight solution calculated to resolve the detected vibration, and where to install it:

The owner’s feedback after dynamic balancing was that his Musketeer felt like a totally new airplane!  Static balancing, followed by dynamic balancing, is a great way to get a smoother flying experience and take stress off of the engine, instruments and airframe.  You can get similar results:  shop for DynaVibe in our online store, or if you have questions, please call us at 650.800.3092, send email to sales@rpxtech.com or enter your email address in the form below.  

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When Prop Balancing Isn't Enough: Troubleshooting Complex Vibrations

Friday, February 26, 2016

This webinar was part of the EAA webinar series and was originally broadcast on February 24, 2016.  It features RPX Technologies co-founder Matt Dock as presenter.


To learn more about using DynaVibe to dynamically balance your prop, or to conduct a vibration survey to pinpoint more complex vibrations, please call us at 650.800.3092 or by email:  sales@rpxtech.com.  If you prefer, enter your email address in the form below and we'll contact you! Shop for DynaVibe by visiting our online store.

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Propeller Vibration Levels Guide

Thursday, January 28, 2016

Many owners and operators ask about what acceptable levels are for propeller vibration and what to do about it.  DynaVibe has prepared the following chart as a guide to understanding prop vibration and when balancing is recommended based on vibration levels:

Aircraft propeller vibration guidelines  

This chart is for information purposes only, and is not intended to replace, supersede or contradict any information in FAA Advisory Circular 20-37E which describes maintenance procedures for owners, operators and FAA certified maintenance personnel for aircraft propellers.  AC 20-37E is a great resource for field propeller maintenance, and it includes a very useful checklist for propeller annual inspection.

Dynamic propeller balancing is easily accomplished using the DynaVibe Classic, for simple balancing, or the DynaVibe GX2 to balance and complete vibration surveys.  The DynaVibe team is always happy to discuss balancing, vibration analysis and resolution, so please contact us if you have questions.  You can reach us by telephone at 469.708.8779, by email at sales@rpxtech.com or simply complete the form below and we'll contact you.  To get pricing or buy a DynaVibe system, visit our online store.

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The Frog in the Kettle: A Prop Balancing Metaphor

Thursday, December 31, 2015

The DynaVibe team can’t help but think of the frog in the kettle as a metaphor for prop balancing.  If you’re not familiar with this anecdote, it tells how a frog reacts to two different situations.  If placed in boiling water, it immediately perceives the danger and jumps out.  But if placed in cold water that is slowly heated, it doesn’t react to the gradual change in its environment and is ultimately boiled to death.  This story is a great metaphor for the inability or unwillingness of people to recognize and respond to gradual change.

Photo © 2010 J. Ronald Lee.

What brought this metaphor to mind was an article recently posted by Paul Dye, editor-in-chief of Kitplanes Magazine.  Paul wrote about his experience using DynaVibe to balance the prop on his RV-3, and he stated:  “It’s the old (probably apocryphal) problem of boiling the frog – if you gradually turn up the heat, it doesn’t know that the temperature is rising. With a slight degradation over time, we don’t realize we are losing balance. Then we reset, and all the smooth magic is back!

Paul nails it.  You just get used to the vibration from imbalance.  It often increases slowly, so a gradual change in vibration isn't noticed.  Many pilots and owners just assume that a certain amount of vibration “comes with the territory.”  It’s the price you pay for combustion engine-powered flight.   But it is wrong.  We get a steady stream of feedback from DynaVibe users and customers of shops that use DynaVibe to provide balancing services.  The feedback follows one of two tracks:

A. Owner whose mechanic or friend talks him into balancing the prop:

  • Owner before: “You can balance the prop if you want, but I don’t have a vibration problem.”
  • Owner after:  “Wow, I can’t believe how smooth it is!

B. Owner who is experiencing a vibration and wants to fix it:

  • Owner before: “The vibration is so bad that it is…. (followed by listing one or more symptoms of the vibration, such as avionics failures, a rough RPM range, fatigue cracks, etc.)
  • Owner after:  “Wow, I can’t believe how smooth it is!

We could go on, but we prefer to let the beneficiaries of prop balancing do the talking for us:

From a FlightLevel Aviation customer:  “While our Bonanza was in for its annual inspection late last year, FL approached us with an option to have the prop balanced. The A36 has the big IO-550, and we felt it ran fairly smooth coupled to a 3 x blade prop. For the relatively small additional price, we opted to try it out anyway. The first time advancing the throttle for take-off after the balancing was complete, I had to look a few times at the MP and Tach gauges to insure the engine was making full power! It ran noticeably smoother through all phases of flight, and the only disappointment was that we didn't do it sooner…."

From a KSFB Aircraft Maintenance Center customer:  “Can’t believe the results!  First run showed it was a long way from acceptable; 0.6 IPS.  The second run we homed in on a better solution; 0.19 IPS.  3rd run was spot on; 0.01 IPS. Compare that with the scale on the LHS [DynaVibe balancing report] which calls 0.05 ‘Excellent’.  The ‘feel’ of the plane, just sitting on the ground in the driver’s seat was remarkably different, too.

From Dennis Barker, President of Reynolds Aviation:  “The pilots were thrilled with how the yoke feels after we balance an airplane. They noticed a difference immediately."

There’s more, and you can read other testimonials on our website.  When it comes to dynamic propeller balancing, perhaps Mark Langford said it best to those who haven’t yet done this procedure on their airplane:  “You guys just don't know what you're missing...

Find out what you’re missing by contacting the DynaVibe team to learn more.  Enter your email address in the form below and we’ll respond to you.  Visit the online store to buy your own DynaVibe unit, email us with your questions at sales@rpxtech.com or just call us if you have questions about the process:  469.708.8779.

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The Top 10 DynaVibe Blog Posts of 2015

Thursday, December 17, 2015

During 2015, the DynaVibe team stayed quite busy creating and publishing new content.  We’ve seen consumption of this content steadily grow, so thanks to everyone who has taken the time to visit our blog and read any of our posts!

Since publishing top 10 lists is in vogue at year-end, we have created one of our own:  the top 10 DynaVibe blog posts from 2015.  We rank them here from 10 to 1, complete with links so you can check them out:

10. Dynamic Prop Balancing: how often to do it?

9.   Airplane Wheel Balancing

8.   Case Study: Complex Vibration Troubleshooting on a Rotax 912

7.   Using DynaVibe to Balance Rotorcraft

6.   Balancing the Antonov 2: the World's Largest Biplane

5.   Identifying and Resolving Aircraft Vibration

4.   Recovering “Lost” Horsepower

3.   Anequim Races to 5 World Records

2.   The Bugatti 100P Flies Again

1.   The Bugatti 100P Flies at Last

We hope you found the content on the DynaVibe blog helpful, and we always welcome comments.  We’ll continue to publish to our blog in 2016, so we hope you’ll follow us there, or on social media:

If you have questions about dynamic propeller balancing or vibration analysis, we're happy to answer them. Please contact us by entering your email in the form below, or by just calling:  469.708.8779. With DynaVibe, we can help you fly safer and smoother next year!

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EAA Sport Aviation Article

Tuesday, December 08, 2015

RPX Technologies co-founder Matthew Dock contributed an article in the December 2015 edition of Sport Aviation - the Experimenter section (pg. 22) of the magazine: "When Prop Balancing Isn't Enough."

In the article, Matt discusses what to do when dynamic prop balancing isn't enough to eliminate a vibration. Click the cover image above to read the article! If what Matt describes sounds like a problem you're having, DynaVibe can help detect a vibration's source, so you can eliminate it.  

If you'd like to learn how the DynaVibe GX2 can help you troubleshoot complex vibrations, contact RPX Technologies by entering your email in the form below or simply call us at 469.708.8779

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DynaVibe Keeps Reynolds Aviation Fleet Flying Smoothly

Saturday, November 14, 2015

Reynolds Aviation provides aerial patrols for pipelines, power lines or any asset that has federal, state, or local reporting requirements.  When on patrol, Reynolds’ highly trained pilots provide security, take aerial photos, respond to emergencies and look for encroachments, leaks, pipeline threats, erosions and construction on right of way assets.   Reynolds uses DynaVibe to help keep its fleet of Cessna 172s flying smoothly while lowering costs of maintenance and operation.

Dennis Barker, president of Reynolds Aviation, has experience with racing engines and therefore knows what damage vibrations can do to an airplane’s engine, its bearings and instruments:  “Vibration can destroy those instruments, so balance is huge!” 

Barker’s partner had previously used a helicopter balancing solution, giving him some frame of reference on the cost of a prop balancer.  When the Aero Performance representative that serves Reynolds Aviation came calling to discuss DynaVibe, Barker expected a pitch for a much more expensive solution costing in the neighborhood of $10,000.  Instead, he learned that he could purchase a DynaVibe Classic and own a dynamic propeller balancing system for less than $2,000, and did so.

Some of the airplanes in the Reynolds fleet were showing signs of fatigue caused by vibration: cracked baffling, new lights that would burn out or instruments that would fail.  Barker knew that eliminating propeller imbalance would stop the damaging vibrations.  “Some of the engines vibrated so badly that we couldn’t even read ‘Lycoming’ that was stamped on the engine.   Now they’re really smooth.“

The prop imbalance on one airplane measured close to 1 Inches Per Second (IPS).  Using DynaVibe, the Reynolds maintenance team was able to balance all the airplanes in the fleet to between .01 and .07 IPS.   The Reynolds pilots often fly long days, spending hours in the air, so eliminating vibration from propeller imbalance not only reduces fatigue on the airplane, but on the pilots as well.  “The pilots were thrilled with how the yoke feels after we balance an airplane,” Barker said.  “They noticed a difference immediately.” 

Barker is confident that using DynaVibe to keep the fleet in balance will also pay dividends in terms of maintenance and operational costs.  “The big enemy of operations like ours is what it costs to keep planes in the air.  Long term, we don’t fully know what the maintenance benefits are, but even cutting these costs by just 10 percent would pay for the DynaVibe system three times over.”

An unexpected bonus from using DynaVibe is the information provided by the photo tachometer, making it possible to determine how accurate the airplane tachometer is.  “An incorrect tach reading can cause us to fly a plane at a cruise RPM that’s actually too high, which can damage the engine,” Barker concludes.  “DynaVibe also tells us if the tach is off.  It’s a phenomenal product.”

To learn about using DynaVibe to dynamically balance propellers and rotors, enter your email address below, visit the RPX Technologies website, or call:  469.708.8779.

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Dynamic Prop Balancing Adds Service Revenue

Tuesday, November 03, 2015

Our new infographic shows how mechanics, repair stations, shops and service centers can make more money by adding prop balancing to their service mix with DynaVibe:

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The Bugatti 100P Flies Again

Thursday, October 22, 2015

DynaVibe was on hand to support Scotty Wilson's second flight with the Bugatti 100P when he returned to Oklahoma's Spaceport at Burns Flat to continue flight-testing.  The Bugatti needed new props after its historic first flight due to a brake failure on touchdown.  The DynaVibe team joined Scotty to balance the two, new propellers on the Bugatti and continue the flight-testing program for this innovative and historic airplane.

Having previously balanced the Bugatti (click here to learn why dynamically balancing a prop is important) for its inaugural flight, a location for mounting the accelerometer was already determined.  It was quick work to install the DynaVibe accelerometer and phototach on the Bugatti.  Balancing the contra-rotating propellers started with the rear engine / rear propeller.  The initial balancing run revealed that the rear prop required 27 grams of correction weight, which when added, brought the propeller imbalance down to 0.09 Inches Per Second (IPS).  The front propeller was then balanced down to 0.10 IPS by adding 18 grams of weight.  Shortly afterward, the Bugatti successfully took to the air once again.

DynaVibe has balanced the Bugatti 100P, the world-record breaking Anequim, warbirdsReno Air Racing team aircraft, the AN-2, the world’s largest biplane, and it can balance whatever you fly, delivering better performance and a smoother flying experience.  To learn how easy and economical it is to dynamically balance your prop with DynaVibe, enter your email address below, visit the DynaVibe online store, or call:  469.708.8779.

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Questions? Contact us at sales@rpxtech.com