Finite Element Applications in the Design of an Outdoor Rotor Testing Facility

Abstract

Computational simulations of the flow fields around a rotorcraft body are extremely complex and difficult to evaluate. Physical testing of rotorcraft body models, while expensive, would provide a direct simpler method of analyzing the aerodynamics of the craft. However, accurate reproduction of the aerodynamic loading imposed on a rotorcraft body due to the propeller wake is difficult to replicate. Aerodynamic loads induced by propeller rotation include both downwash and rotation in the air stream around the aircraft. Traditional wind tunnels normally provide only one dimensional air flow which does not always accurately simulate the rotation of the downwash induced by the rotor. Adding devices to a wind tunnel to induce rotation in the air stream is possible. However, it still does not provide an accurate simulation of the rotorcraft’s wake. In order to accurately analyze the aerodynamics of rotorcraft bodies, West Virginia University’s (WVU) Center for Industrial Research Applications (CIRA) has designed a Facility for Outdoor Rotor Testing (FORT). This design consists of a structure equipped with a propeller to transmit airflow across a model of a rotorcraft body. The airflow induced by the propeller is provided to simulate an accurate representation of the downwash present in rotary-winged aircraft, as well as to introduce measurable environmental effects, such as wind gusts and temperature changes to the model in order to create a more realistic flight environment under which the model can be studied. This paper describes the implementation of finite element analysis (FEA) in the design and verification of the FORT support structure which will secure the motor and propeller during operation.