Jan 12 2012

Helicopter Safety, Less Vibration Is Better Posted 12 years 352 days ago ago by Admin

By Eli Navon - The Helicopter is really a bunch of parts flying in relatively close formation. Things work well until one of the parts breaks formation. Vibrations are one of the biggest enemies to helicopter health condition. It is generally accepted that less vibration is better than more vibration.

From decades of operating rotary wing aircraft, military organizations around the world, as well as many civil manufacturers and operators of helicopters, have learned that one of the biggest enemies to sustained normal safety and flight operations is high vibrations throughout the drive train, rotors and fuselage.

Component failure, imbalances in the drive train, uneven friction, and the uneven meshing of gear teeth, cause such vibrations. Rotary wing operators worldwide have borne the costs of dynamic component failure due to damaging vibrations, long before predicted time before overhaul (TBO).

“Vibration causes an unplanned accelerated reduction of the airframes useful life thereby increasing operating and support (O&S) costs and decreasing both aircraft availability, safety of flight, and logistics supportability” Says Eli Navon CEO of Shake’d Technologies a New York based company specializing in solving helicopter vibration challenges.

It has been observed that safety-related problems in various parts of the aircraft have arisen from vibration causes: cracked welds, cracked fuselages, loose wiring connections, and in-flight failure of dynamic components. Attempts within industry to address these problems have mostly focused on monitoring vibration data in an attempt to predict useful life of dynamic components or to warn of imminent component failure. None of these solutions were intended to actively reduce or eliminate the damaging vibration, only to monitor it.

A NEW SOLUTION
Customized Dynamic Balancing (CDB) is a unique, newly developed technology that employs a complex proprietary set of algorithms aimed at eliminating destructive vibrations considering the whole drive train as one unit. Beyond just monitoring for vibration, the CDB algorithms analyze collected vibration data to determine the specific solution for each individual aircraft in order that its drivetrain may be custom balanced, eliminating vibrations. Each aircraft drive train is then physically balanced within its own vibration profile using the solution given. The dramatic immediate results our system is demonstrating in harsh operational environments when operated only by soldiers is providing the Army with a key technology enabler that is transforming the way maintenance is done today.

I believe CDB emphasizes the importance of the dynamics of the whole drive train, and the interaction between its inter- dependent parts, rather than isolating by analyzing the drive train by specific components. CDB is concerned with a holistic approach, rather than the analysis of separate components.

The CDB technology supports 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 vice unscheduled maintenance, thereby reducing extensive aircraft on ground events. This Preventive Maintenance process keeps the vibration deterioration rate very low and moves component lifetime closer to TBO. The longer a dynamic component remains on-wing, the lower the operating cost to the operator.

By immediately reducing vibration in the drive train, and periodically checking and re-balancing the aircraft as required, (every 200-250 flight hrs.) the aircraft can achieve and maintain a minimum vibration profile over its life. Helicopters without CDB will have a certain rate of vibration increase that is as components wear over time, their vibration levels will increase at a certain rate. This rate historically is exponential in nature.

HOW IT WORKS
The concept of operation is simple. There are accelerometers temporarily placed in designated locations along the drive train, along with sensors, the aircraft is then run on the ground and measurements are taken. The computer then analyzes the information, calculates a solution, and displays it to the technician. The technician follows the solution instructions and performs the adjustments to the drive train. After applying the solution to the drive train, a verification run is performed to confirm the immediate reduction in vibration. Then, the sensors are removed along with the special cables and the aircraft is returned to service. The entire process takes an average of two hours for the first balancing run. Subsequent runs historically take much less time, sometimes as little as 30 minutes. As part of the balancing process the system checks additional conditions such as onboard sensors are checked for accuracy, aircraft clutch health condition, accessory gearbox is examined, gearboxes modulation and hangar bearings performance are examined.

About the Author:  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 Europe 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.