Sikorsky Aircraft Design

Team – Stage II

Active, Open – Loop Vibration Control of

Scale Model Apache Helicopter Tail Boom

Team Members: Adam Long, Hagan Baturay, Michael Kienzle, and Patrick Farabaugh

Special Thanks: Bill Welsh (Sikorsky), Dr. Edward Smith, Dr. Joseph Szefi, Dr. John

Lamancusa, Michael Philen, and Michael Evert at CSA Engineering

Sikorsky Aircraft Corporation is a leading company in the design and production of advanced helicopters for commercial, industrial, and military use. For the past two years Sikorsky and The Pennsylvania State University have been working together to reduce the vibration that occurs in the tail boom section of a helicopter. A one-third scale vibration absorber was developed in a previous semester’s Senior Design Project to control the first bending mode of a one-third scale Apache helicopter tail boom. In the current phase of the research, the new objective is to design, fabricate, and test an open loop configuration of a design based on the passive prototype. This objective has been accomplished using key elements found in the passive prototype and then refining and optimizing that team’s design. An inertial force actuator from CSA Engineering provides the active, controllable vibration cancellation force. This design proved to significantly reduce the amount of vibration at the natural frequency of the tail boom.

Executive Summary:

Design:

Results:

Conclusions:

• The new prototype design is lighter overall and yet more effective as a vibration absorber, because it uses its mass more efficiently than the passive absorber.

• The new prototype design reduced the free vibration amplitude of the tail boom by 90%. The active absorber was also 62% better than the passive absorber at the tested frequencies.

• The new design builds the groundwork for a greater bandwidth of vibration absorption using closed-loop control schemes, which are to be developed in the near future.