Active Balancing: Coming Soon to an Aircraft Near You?

The accelerometers monitor vibration levels and send their input to the controller. The controller constantly monitors input from all the accelerometers. If an unbalance is present, it signals the corresponding balancing unit to make a correction.

The balancing unit is mounted directly on the propeller. It is a ring with internal weights. The weights are shifted based on signals from the controller.

If for some reason a propeller is unable to be balanced by the balancing unit, the controller would send an indication to the crew allowing for the maintenance team to take corrective maintenance as needed.

Benefits

The obvious benefit to active balancing is that the propeller is constantly being monitored and balance is being corrected. This results in greater passenger comfort and less strain on the engine, airframe, and components. In addition, the time- consuming task of performing a dynamic balance can be eliminated.

The IFPB can significantly reduce vibration levels. According to Steve Meyer, Lord defense business development manager, based on earlier U.S. Navy NP2000 propeller ground tests, the IFPB system can be expected to reduce the average propeller vibration level during flight by a factor of five to 10 (to 0.05 ips) when compared to standard dynamic balancing. Meyer says that potential users of the IFPB system include USAF C-130 and the U.S. Navy P-3 and E-2C/C-2A.

Proven Technology

The active balancing system that has been developed by Lord Corporation leverages technology that has been proven in commercial applications. Electromechanical balancing technology has been in service in industrial applications for around a decade logging millions of hours of service in applications ranging from turbo-compressors to large extraction fans and high-speed machining spindles.

Drawbacks

If there is any drawback at this time, it is that this technology is not yet in service. But Lord continues to speak with the military and OEMs to develop applications that can benefit from IFPB technology. In the future, dynamic propeller balancing on the ground may be a thing of the past. Only time will tell. Stay tuned for more coverage of this emerging technology.