Non-Contacting Torque Sensor for Helicopter Tail Rotor Drive Systems.

There is an increasing need for an accurate (within 2%) method for measuring the torque of a helicopter tail rotor shaft. Current methods are expensive and suffer from a number of other flaws including complicated manufacturing/installation issues, limited accuracy (5%), and so on. International Electronic Machines (IEM) Corp., a leader in the field of sensor instrumentation technology for transportation applications, proposes to develop a non-contacting torque sensor for helicopter tail rotor drive systems. This system will build upon the results obtained in the Phase I work on this same topic; in this Phase I work IEM determined that the preferred approach will involve magnetic encoder technology. The final product of the Phase II research will be a system which is: accurate to 1% of full-scale torque (making considerable extra power available for maneuvering), inexpensive, easy to install/maintain, reliable, able to log rotor data for analysis or use in fatigue models, fast for tracking transient loads, and adaptable to various shaft locations. Boeing, the manufacturer of the Chinook rotorcraft which is the specific subject of this research, was favorably impressed by IEM's preliminary work and has offered assistance for the Phase II effort and potential financial support for later commercial development.