Finding Solutions To Dangerous Aircraft Vibrations

It is generally agreed that less vibration is better than more vibration. It makes the simplest and most basic sense. Some vibrations are believed to occur because drive-train components (such as the driveshaft, rotor blades, gearboxes, etc) are balanced independently at the manufacturer level and when assembled on to the aircraft, the entire drive-train is not balanced as “one unit”. Therefore, vibrations travel along the entire aircraft drive-train and fuselage and transmitted to different areas, and it is this belief that has propelled Shake’d Technologies, Inc., a New-York based company specializing in the development of advanced rotary wing innovations, to find a solution. The company developed Customized Dynamic Balancing (CDB), which unlike other methods, approaches the entire aircraft vibration analysis as a whole, rather than by its inter-dependent parts. According to company CEO Eli Navon, “The unique process efficiently and immediately identifies the root cause of vibration problem and provide with a dynamic solution to fix it.

According to Eli Navon, the CDB technology was developed to specifically eliminate the damaging effects of inherent drive-train vibrations, using a proprietary set of algorithms the system analyze the vibration data to determine a specific solution for each individual aircraft. In this way, each drive-train is custom-balanced within its own vibration profile using the solution given.

“The tuning process relies on accelerometers temporarily placed in designated locations along the drive-train that measure vibration levels and other required data. The aircraft is then run on the ground as measurements are taken. The computer analyzes the gathered information, calculates a solution, and displays it to the technician. The technician follows the solution instructions and performs the adjustments to the drive-train,” Navon continues “As soon as the necessary solutions are applied, a verification run is performed to confirm the immediate reduction in vibration. Then, the sensors are removed and the aircraft is returned to service. The entire process takes an average of two hours for the initial run. Subsequent runs could take as little as 30 minutes.” He says that depending on the helicopter platform, CDB recommends the users to apply the solution every 200 flight hours to ensure constant operation with minimal vibration levels.

The balancing process is best done during a ground run because the vibration data transmitted through the aircraft drive-train during ground run gives a much more precise vibration profile, eliminating the differences of changing torque loads on the drive-train components in flight. Navon says,. “torque loads transmitted while airborne are constantly changing due to flight conditions, which greatly affect vibration levels and distort the measured vibration, resulting in a misleading picture of the actual vibration profile,” he explains.

“These types of programs support the Condition Based Maintenance (CBM) concept by providing Reliability, Availability, and Maintainability (RAM) data that supports predictive maintenance practices based on actual conditions of dynamic components vs unscheduled maintenance. Navon says, CDB is very useful in identifying and troubleshooting failures beyond the drive-train, it also avoids the costly ‘guesswork’ incurred by maintainers who waste time and money trying to find the root source of a particular problem”. Maj. Gen. (Ret.) Eitan Ben Eliyahu, former Commander of the Israeli Air Force (IAF), and an aviator for 38 years attests, who is a strong supporter of the program.

“This unique technology includes main rotor track and balance during ground run, so that the aircraft can be serviceable after only one test flight in the air,” Navon said. “Additionally, the solution is able to examine the health condition of each gear mesh in all gearboxes and report unusual behavior to the user. By immediately reducing vibration in the drive train, and periodically checking and re-balancing the aircraft as required, the aircraft can achieve and maintain a minimum vibration profile over its life,” Eli Navon said.

Experimental test pilots who have flown an Apache aircraft immediately after applying CDB said “it has made an obvious difference, not only are the vibrations way down, the noise in the cockpit is quieter”.

Eli Navon points another important attribute of the CDB is its ability to integrate (in full or in part) with other health and usage monitoring systems. Since the critical part of the CDB system is software, integration efforts would mostly involve software integration engineering. Collected data can be passed to the CDB system via a digital storage device (digi-stick), or other similar means, and loaded into the technician’s computer for processing and balancing solution

CDB has been utilized by an international fleet of rotary wing aircraft for over three years now. According to Navon, test pilots are impressed, saying that applying the solution has made an obvious difference in their aircraft. Today, Shake’d Technologies says that the solution is fully developed and proven to be very effective in reducing costs and increasing aircraft availability, safety, mission readiness and logistics supportability.

ELI NAVON is a businessman whose involvement extends throughout the defense, aviation technologies and real estate Industries. seven years ago, he entered the defense industry and since then, he has worked on many successful projects. Navon’s contribution to defense industry spans from United state to Euorpe and the Israeli defense market place. Eli Navon is known for his business acumen, penchant for detail and perfection, as well as a disciplined approach for business, management and finance. His trained vision for new opportunities has lead to numerous successful projects. Eli Navon served in the Israeli Defense Force (IDF) and is a successful 3rd generation entrepreneur.