Hardesty, Mark | Engineering Papers

NASA NTRS1999

AHS Technical Committee Highlights: Test and Evaluation

The AHS technical committee for Test and Evaluation is comprised of representatives from industry and government rotorcraft technology development centers. The committee considers many aspects of rotorcraft and VTOL testing, including the evaluation of components and subsystems. In addition, the committee seeks to evaluate the effectiveness of new procedures and operational solutions to problems that are encountered in the low-speed flight regime for both land and ship-based environments. This article presents the test and evaluation committee highlights for 98-99. Though by no means comprehensive, the article includes significant efforts related to test and evaluation contributed by the committee members for their respective organizations.

Jacklin, Stephen A.↗

NASA NTRS1987

Helicopter main-rotor speed effects on far-field acoustic levels

The design of a helicopter is based on an understanding of many parameters and their interactions. For example, in the design stage of a helicopter, the weight, engine, and rotor speed must be considered along with the rotor geometry when considering helicopter operations. However, the relationship between the noise radiated from the helicopter and these parameters is not well understood, with only limited model and full-scale test data to study. In general, these data have shown that reduced rotor speeds result in reduced far-field noise levels. This paper reviews the status of a recent helicopter noise research project designed to provide experimental flight data to be used to better understand helicopter rotor-speed effects on far-field acoustic levels. Preliminary results are presented relative to tests conducted with a McDonnell Douglas model 500E helicopter operating with the rotor speed as the control variable over the range of 103% of the main-rotor speed (NR) to 75% NR, and with the forward speed maintained at a constant value of 80 knots.

Mueller, Arnold W.↗