Accession Number:

ADA537657

Title:

Performance and Flowfield Measurements on a 10-inch Ducted Rotor VTOL UAV

Descriptive Note:

Conference paper

Corporate Author:

ARMY RESEARCH DEVELOPMENT AND ENGINEERING COMMAND MOFFETT FIELD CA AVIATION AEROFLIGHT DYNAMICS DIRECTORATE

Personal Author(s):

Report Date:

2004-06-01

Pagination or Media Count:

21.0

Abstract:

A ducted fan VTOL UAV with a 10-inch diameter rotor was tested in the US Amy 7-by-10-Foot Wind Tunnel. The test conditions covered a range of angle of attack from 0 to 110 degrees to the freestream. The tunnel velocity was varied from 0 simulating a hover condition to 128 ftsec in propeller mode. A six-component internal balance measured the aerodynamic loads for a range of model configurations, including the isolated rotor, the isolated duct, and the full configuration of the duct and rotor. For some conditions, hotwire velocity surveys were conducted along the inner and outer surface of the duct and across the downstream wake. In addition, fluorescent oil flow visualization allowed the flow separation patterns inside and outside of the duct to be mapped for a few test conditions. Two different duct shapes were tested to determine the performance effects of leading edge radius. For each duct, a range of rotor tip gap from 1R to 4.5R was tested to determine the performance penalty in hover and axial flight. Measured results are presented in terms of hover performance, hover performance in a crosswind, and high angle of attack performance in propeller mode. In each case, the effects of both tip gap and duct leading edge radius are illustrated using measurements. Some of the hover performance issues were also studied using a simple analytical method, and the results agreed with the measurements.

Subject Categories:

  • Aerodynamics
  • Helicopters
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE