Flow Environment Study Near the Empennage of a 15-Percent Scale Helicopter Model
Abstract
Development of advanced rotorcraft configurations has highlighted a need for high-qualify experimental data to support the development of flexible and accurate analytical design tools. To provide this type of data a test program was conducted in the Langley 14- by 22-Foot Subsonic Tunnel to measure the flow near the empennage of a 1 5-percent scale powered helicopter model with an operating tail fun. Three-component velocity profiles were measured with laser velocimetry (LV) one chord forward of the horizontal tail for four advance ratios to evaluate the effect of the rotor wake impingement on the horizontal tail angle of attack. These velocity data indicate the horizontal tail can experience unsteady angle of attack variations of over 30 degrees due to the rotor wake influence. The horizontal tail is most affected by the rotor wake above advance ratios of O.10. Velocity measurements of the flow on the inlet side of the tail tan were made for a low-speed flight condition using conventional LV techniques. The velocity data show an accelerated flow near the tail tan duct and vorticity calculations track the passage of main rotor wake vortices through the measurement plane.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2000
- Accession Number
- ADA406405
Entities
People
- Deane G. Reis
- John D. Berry
- Susan A. Gorton
- W. T. Hodges
Organizations
- National Aeronautics and Space Administration