Annual Inspection Time
Every aircraft owner knows the drill: it's annual inspection time, a mix of routine yet hopeful checks to ensure our planes are in tip-top shape. Our Cessna 210, a reliable performer, entered this inspection with us feeling confident. After all, we'd been diligent with maintenance, and the engine was running as smooth as ever.
However, things didn’t quite go as planned. One cylinder came up a bit shy on the compression test. Turning to Continental’s SB03-3 bulletin for guidance, we flew it for another hour, hoping for a pressure change that didn’t materialize. So, it was time to remove and inspect the cylinder. With hindsight being 20/20, perhaps a ring wash should have been tried as well.
The real curveball came after the cylinder was removed. Hidden from routine view, our mechanic identified a subtle flaw on one of the cam lobes. This small gouge, while easy to overlook, did have a depth significant enough to snag a metal pick. Those versed in aircraft maintenance might recognize this as a warning threshold, per the indicators in Service Information Directive SID05-1. An email exchange later, Continental verified that the cam needed to be replaced. Thus began our unexpected journey into a deeper teardown.
Unsettling to Downright Frustrating
We entrusted our engine to SkyBoss Aviation, a reputable aircraft engine overhaul service facility just outside of Tulsa, OK. Bill Wagner, the seasoned expert over at SkyBoss, took on the task of disassembling our engine. But not long after, he rang us with news that got our attention.
Firstly, Bill described the engine's interior akin to a swamp at some point in its lifetime. Internal corrosion was everywhere, rendering many components unfit for service. A complete engine overhaul was the only way forward.
But then came the kicker. The crankshaft bearings were out of stock. And if that wasn’t enough, approval paperwork for a bearing manufacturing change had yet to be approved by the FAA, effectively putting an indefinite hold on their availability.
What we initially hoped would be a few months' delay extended far longer than we ever anticipated, clocking in at a frustrating year-plus of waiting and a staggering invoice of $40,603.
Battling the Silent Killer: Engine Corrosion
The extent of our engine's corrosion was shocking. With part after part deemed irreparable, we grappled with not only the mounting expenses but also significant downtime. Furthermore, over a year’s worth of adventures in the 210 were lost. Not to mention the currency and proficiency of an owner-pilot that relied exclusively on this particular aircraft.
This ordeal made us hyper-aware of engine corrosion, prompting us to introduce engine dehydrators across our fleet of five personal and corporately owned aircraft.
We tested several market-available engine dehumidifiers but found ourselves questioning their efficacy. It was disconcerting to often even see water collected in the tube meant to aerate the engine – a clear indication that something wasn't right!
With the drive to understand the situation better, we repurposed small dataloggers (manufactured by us for a different venture) to fit snugly into spark plug holes and crankcase vents. After installing the dehydrators, these sensors began to record the humidity levels inside of our engines and confirmed the dehydration devices' ineffectiveness.
For example, our month-long logging exercise for the Long-EZ engine yielded revealing results. The dehydrator initially seemed promising, maintaining a dry environment for about a day. But soon after, the internal humidity levels surged, often breaching the 40% and 50% thresholds. Clearly, this solution wasn't cutting it. And other dehydration methods required constant user intervention which made them impractical. It was off to the drawing board to find a more effective, reliable solution to this problem.
Birth of the DryBot - The Ultimate Guardian Against Engine Corrosion
Our search for a solution finally hit a wall. We felt that the market simply didn’t offer a system that was maintenance free and effective in keeping the internal engine humidity below the crucial corrosion-inducing level of 40%. We, and the rest of the aviation industry, needed a reliable solution.
Harnessing our passion for aviation and our team of in-house engineers, we set out to design the solution the aviation world was missing: the DryBot. Envisioned as the gold standard of engine dehydrators, DryBot would promise not just reliability, but also minimal upkeep. Its unique self-monitoring features would ensure it's always operating correctly, giving aircraft owners that much-needed peace of mind.
In essence, with DryBot, we didn’t just aim to solve our own corrosion problems; we wanted to offer the broader aviation community a trustworthy guardian against the silent but menacing threat of engine corrosion and avoidable early overhauls.
Inside the DryBot: A Deep Dive into its Innovative Design
The DryBot, our answer to the aviation industry's engine corrosion challenge, is a culmination of extensive research, rigorous testing, and our own frustrating experiences with other systems. Let's unpack what makes DryBot different:
1 - Reliable Dehydration
Our search for the perfect dry air source took us through various technologies, from refrigeration systems to desiccant media. Ultimately, desiccant beds emerged as the most dependable method, consistently delivering the dry air needed to prevent engine corrosion.
2 - Truly Maintenance-Free
Desiccant-based dehydrators do come with a catch: over time, the desiccant gets loaded with water and needs either replacement or regeneration. Our solution? A specially designed airflow circuit, complete with an integrated regeneration heater and alternate valve actuated airflow path used to expel water. This approach regenerates the desiccant as and when required, eliminating the need for manual intervention.
3 - Smart Self-Monitoring
If there's one thing we've learned, it's the importance of reliability. With many systems, you're left wondering if they're doing their job. Is the air dry? Is the air flowing? This isn’t a problem with the DryBot. The DryBot is equipped with a suite of internal sensors that continuously monitor airflow and humidity output. And for a quick status check? A straightforward Green/Red light system flags if everything's running smoothly or if, say, there's a kinked hose blocking flow.
4 - Ultimate Trustworthiness
At its core, DryBot's mission is simple: keep the air dry and keep it flowing. But we didn't stop there. We incorporated an inline particle filter, ensuring that not only is the air dry, but it's also clean. Furthermore, safety is paramount, so we added a mechanical thermal thermostat to serve as a backup for controlling heater temperatures. Paired with our heater power measurement circuitry, these sensors work to detect and flag any heater faults.
Validating the DryBot: Real-World Data
Our journey with the DryBot wasn't just about engineering a solution, but also ensuring that it was truly effective. That assurance lies in the real-world data our humidity dataloggers captured.
In the initial phase, without the DryBot, the data displayed the engine's internal humidity levels mimicking ambient levels but slightly lagging due to the thermal mass of the engine and engine air leakage.
Once the DryBot was initiated on day 2, the change was almost immediate. Within minutes, the internal humidity plummeted to 0%. Detecting a rise in output humidity, the DryBot automatically triggered a regeneration cycle of the desiccant bed roughly once per day. While regenerating, the DryBot heats the desiccant bed and purges its moisture, releasing the absorbed water through a discreet opening at its base. Our data vividly illustrates this process: during these purging episodes, the internal humidity saw only a modest uptick, thereby keeping the internal engine humidity between 0% and 20% RH. This is well below the 40% threshold where steel exhibits substantial rates of corrosion.
The journey of developing and validating the DryBot has been a testament to the importance of innovation in aviation maintenance. It's not just about a piece of technology, but the peace of mind it brings to aircraft owners, knowing their engines are safeguarded. In an industry where precision and reliability are paramount, the DryBot stands as a genuine contribution to preserving the longevity and safety of our aircraft.
Warren Cilliers owns Cilliers Aviation, a maintenance business in Palatka, Florida, where he works primarily on aerobatic airplanes, such as the Extra 330SC. He also travels the world as technician for Michael Goulian and Team 99, as Goulian competes in the Red Bull Air Race World Championship. In both endeavors, Cilliers uses a DynaVibe Classic to perform dynamic propeller balancing. “Definitely used the DynaVibe and it’s really helped us out,” says Cilliers.
In the past year, Cilliers estimates he has used DynaVibe to complete 40 prop balances. “That's without advertising,” says Cilliers. “It's really just my customers that come through my shop and word of mouth in the area. It's been great.”
Cilliers understands the preventative maintenance benefits of keeping propellers balanced: “It's obviously very important on any aircraft, not only aerobatic airplanes, for fatigue and wearing of parts, gears in the engine, magnetos, everything, even going down to fatigue on the airframe, with vibration and cracks on the aluminum and things like that.” Because of the benefits, dynamic balancing with DynaVibe has become a standard procedure Cilliers does for his customers. “It's so easy to work. I've got it down to an art now, where I can just take it out in my ground run, and just balance it for them. They really appreciate it.”
Cilliers is getting great results from balancing with DynaVibe that his customers can feel. “I've never had any negative report back from any customer. Whenever I do a balance, even if it's not as much out-of-balance [to start with] – where I think the customer would not even feel it – they always report back that they notice a difference.”
Customers feel the difference and get the benefits of Cillier’s balancing work. With DynaVibe, the balancing process is easy and the payback on the investment in the balancing equipment has been excellent. “The simplicity of DynaVibe makes it easy. It's been great, and well worth the $1,600 that I've spent. I've probably paid for it about 10 times already, so I’m very, very pleased with it.”
DynaVibe with DynaTrack Simplifies Track-and-Balance for Sheriff Department's Helicopter Fleet, Improving Maintenance and Pilot Comfort
Whether you’re maintaining a fleet of helicopters or a single ship, blade tracking and balancing shouldn’t be a full-time job. When you do pull out your tools to do your next track and balance, will the tools complicate the task, or simplify it? RPX Technologies recently spoke with the mechanic for a county sheriff aviation unit in the southeast U.S. about the right tool for the job and how switching to the DynaVibe GX with DynaTrack made his job easier.
The department had previously purchased a competing track-and-balance system, but this mechanic shared that “I'd go for long periods of time and we didn't have to do a track and balance, and then you kind of relearn it every time you do it.” The mechanic recalled that the competing system “was way smarter than I was and a little more complicated than I was used to working with. I struggled through using it a few times and at one point, I contacted manufacturer for a field rep to come and help me again. They were willing to do it, but they were going to charge us an extreme amount of money to do that, to train us. That's the time I figured we needed to start looking at something a little less complicated.”
The DynaVibe GX3 balancer when coupled with the DynaTrack optical blade tracking system is efficient, accurate, affordable, and easy-to-use to perform helicopter blade track-and-balance. “We purchased a DynaVibe system,” noted the mechanic. “It's easy to install and set up. To operate it… probably took me less than an hour and 45 minutes to get everything done.”
His first use of the DynaVibe balancer was on a ship where the crew had just changed out the main rotor hub. During the initial track and balance process, he found that “the vertical wasn't too bad, but the lateral vibrations were pretty bad,” explained the mechanic. “After I made the PC link adjustment to bring the blade down, that helped the lateral quite a bit. And then on the second run after that, the DynaVibe system told me that I needed to add weights to the blank blade bolt and I did that. You could feel it just getting better on each run. I was impressed. We finished tracking it out and I was really happy with the way the system works.”
The department has multiple OH-58 helicopters and the mechanic’s goal is to always have at least two aircraft available for flight operations. As important is ensuring the helicopters are not degrading the ability of the crew to function. “There's always a primary and a backup aircraft,” explained the mechanic. “Our guys fly missions and they'll do orbits over the target area, and they fly three to four hours a day sometimes. It's easier on them, when they're not getting beat to death by the aircraft being out of track, and it's easier on the aircraft too.”
This mechanic summarizes his experience using DynaVibe and DynaTrack: “I’m really happy with the way the system works and everything. The RPX rep called and checked on me to see how my progress was, and we sat and talked about the readings I was getting and everything. I'm real satisfied with the service. There’s a great support system there for the customer, and that's a good selling point for these systems. Kudos to the DynaVibe guys; they’ve got a good product.”
Visit the Rotorcraft section of the RPX online store, or click the yellow "Contact Us" tab below to learn more about helicopter track-and-balance solutions.
Proud owner of a Jet Exec (turbine) RotorWay helicopter, Joseph Luiz completed his build in late 2017. In attendance for the 2015 EAA AirVenture fly-in convention (Oshkosh), he scoured the grounds to find an affordable, easy-to-use track and balance system for his RotorWay copter. Joe states “I went to Oshkosh with a mission; I went to every single booth that was providing this type of equipment because I needed something that worked flawlessly and provided peace of mind."
Before acquiring a track and balance solution, Joe had an unsuccessful attempt to balance the high-speed tail rotor on his RotorWay. “I ended up bending a shaft because I really didn't know how to properly balance.” At AirVenture, Joe visited the RPX Technologies booth where he discovered and bought a complete DynaVibe system with the DynaTrack optical tracking accessory. The DynaTrack simplified the helicopter track and balance with built-in setup information specifically for his RotorWay, as well as a compiled database of other helicopter systems.
Joe is using DynaVibe and DynaTrack to perform dynamic main and tail rotor balancing, as well as blade tracking. “It's been very simple and easy to use. With rotorcraft, you've got all this dynamic action occurring in unison, so it has to be just right. There is truly no margin of error, and I found DynaTrack helps eliminate that error.” He was able to track and balance his RotorWay’s main blades in a hover with one reading and one slave blade adjustment. DynaTrack representatives recommended that he begin the process by doing a hover track to make an initial assessment: “I did the readings and found I was three quarters of an inch out on my slave blade. I consulted the documentation, and it looked like I needed to make a pitch change on the slave blade to bring it down to match the master blade. I made a half turn on the slave blade and brought it within a tenth of an inch, and it was a night and day in performance. It was amazing, and I did that with one measurement! The change in performance and vibration levels was just phenomenal.”
Joe continues to use his DynaTrack to achieve optimal performance. “I'm flying, and I'm doing my dynamic main rotor blade tracking right now using the DynaTrack.” Joe also uses the DynaVibe system to balance the tail rotor. The result is a smoother flight and peak performance. Eliminating the vibrations that come from unbalanced or out-of-track rotors also reduces stress on the airframe, engine, and instruments. “For the amount of money that I spent and the functionality of the equipment, it was a no-brainer. The price was important to me because I'm not in the business of doing this. I wanted to get the best equipment I could without breaking the bank. Overall, I'm very satisfied with the equipment.”
His advice to fellow builders and/or owners? “Don’t beat around the bush on this one, the DynaTrack will ultimately save you thousands of dollars in prevented misbalances, provide optimal performance, and ensure peace of mind in its use. Simply put: just buy it.”
Learn more about DynaTrack by clicking on the yellow, "Contact Us" tab near the bottom of this page.
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 aircraft 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 405.896.0026, firstname.lastname@example.org, or click on "Contact Us" tab near the bottom of this page to enter your email address or phone number and we’ll contact you!
David Trotter is Director of Maintenance at Chris Air, an agricultural operator that flies out of Lake Village Municipal Airport (M32) in Lake Village, Arkansas. David recently purchased a DynaVibe Classic, and after using it contacted us to share his experience using the system.
David balanced three of his aircraft, getting the prop imbalance balance on one of them down to .01 Inches Per Second in four run-ups. David shared, “We would normally be flying the airplanes about 40 miles to another shop for prop balancing. By my estimation we have already paid for the unit!”
Matthew Mitchell operates Mitchell Flying Service, an agricultural aviation operator based out of Perry Municipal Airport (F22) in Oklahoma. Mitchell has been flying since 1990 and puts about 250 to 300 hours per year on his Grumman Ag-Cat, for which he has two TPE-331 engines that he rotates as needed. The rigors of agricultural aviation have shown Mitchell the value of keeping the prop on his Ag-Cat in good balance, which is done using a DynaVibe GX2.
Anytime something changes with the prop, such as maintenance or mounting the prop after an engine change, Mitchell likes to have a dynamic balancing performed. “It is essential to have the prop balanced,” states Mitchell. Doing so eliminates vibration caused by propeller assembly imbalance, which reduces wear on the engine, airframe and instruments. Dynamically balancing a propeller is an excellent preventative maintenance approach that can help eliminate future engine problems that might otherwise ground an operator.
Another significant benefit to using the DynaVibe GX2 is the vibration survey capability it provides. “DynaVibe checks other vibration ranges besides the propeller,” says Mitchell. “It’s a good way to keep an eye on the engine, because you may not feel a vibration that DynaVibe can detect.” Anytime Mitchell puts an engine together, he likes to have a baseline vibration analysis done. This allows him to do trend monitoring on the engine with DynaVibe to monitor the health of that engine while it is in use. Regular vibrations surveys can help operators like Mitchell to identify problems before they cause a shutdown or result in a failure.
The DynaVibe GX2 is a dynamic prop balancer and vibration analyzer that can improve performance and maintain engine health. To get your own DynaVibe GX2, visit the RPX Technologies online store, enter your email address below or simply call us at: 405.896.0026.
KSFB Aircraft Maintenance Center is located in Seminole County, Florida, and is operated by Chris and Lisa Reilly. Chris is an A&P technician with Inspection Authorization. He is also a private pilot and aircraft owner. Included among the many services he provides to his clients is dynamic propeller balancing, which he uses a DynaVibe GX2 to perform.
Chris recently dynamically balanced a client’s Cozy Mk IV with a Lycoming IO-360 (fuel injected) engine and a Sensenich wooden cruise prop. His client was pleased with the outcome and sent Chris some feedback email message to share his thoughts:
“After finishing the installation of Belleville washers my prop (ask me why), I suspected those huge, new steel lumps under each prop bolt would play havoc with whatever primitive balance I’d achieved during the build, so today I had my local A&P do a dynamic balance.
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] below which calls 0.05 'Excellent'.
The 'feel' of the plane, just sitting on the ground in the driver’s seat was remarkably different, too. I’ll put the cowls back on and fly it at the weekend, but I’m expecting a gross improvement. I’ll report results.
Most engineering exercises are a compromise. With this result, I drove home with a big smile on my face!
If you haven’t already done this [balance your prop], give yourself a Christmas present!”
DynaVibe gives pilots a smoother, safer flying experience, and provides maintenance centers with a new source of revenue. To get your own DynaVibe system, visit the RPX Technologies online store, enter your email address below or simply call us at: 405.896.0026.
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: 405.896.0026.
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, warbirds, Reno 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: 405.896.0026.