NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Flow visualization of mast-mounted-sight/main rotor aerodynamic interactionsFlow visualization tests were conducted on a 27 percent-scale AH-64 attack helicopter model fitted with various mast-mounted-sight configurations in an attempt to identify the cause of adverse vibration encountered during full-scale flight tests of an Apache/Longbow configuration. The tests were conducted at the NASA Langley Research Center in the 14- by 22-Foot Subsonic Tunnel. A symmetric and an asymmetric mast-mounted-sight oriented at several skew angles were tested at forward and rearward flight speeds of 30 and 45 knots. A laser light sheet seeded with vaporized propylene glycol was used to visualize the wake of the sight in planes parallel and perpendicular to the freestream flow. Analysis of the flow visualization data identified the frequency of the wake shed from the sight, the angle-of-attack at the sight, and the location where the sight wake crossed the rotor plane. Differences in wake structure were observed between the various sight configurations and slew angles. Postulations into the cause of the adverse vibration found in flight test are given along with considerations for future tests.
Document ID
19930063283
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Ghee, Terence A.
(Analytical Services and Materials, Inc. Hampton, VA, United States)
Kelley, Henry L.
(U.S. Army, Aeroflightdynamics Directorate; NASA, Langley Research Center Hampton, VA, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1993
Publication Information
Publication: In: AIAA Applied Aerodynamics Conference, 11th, Monterey, CA, Aug. 9-11, 1993, Technical Papers. Pt. 2 (A93-47201 19-02)
Publisher: American Institute of Aeronautics and Astronautics
Subject Category
Aircraft Stability And Control
Report/Patent Number
AIAA PAPER 93-3517
Accession Number
93A47280
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available