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Span-wise wind fluctuations in open terrain as applicable to small flying craft

Published online by Cambridge University Press:  27 January 2016

M. Thompson,
S. Watkins,
C. White and
J. Holmes
M. Thompson
Affiliation:
RMIT University, Melbourne, Australia
S. Watkins
Affiliation:
RMIT University, Melbourne, Australia
C. White
Affiliation:
RMIT University, Melbourne, Australia
J. Holmes
Affiliation:
JDH Consulting, Mentone, Australia
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Abstract

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Micro air vehicles (MAVs) are typically of low mass and moment of inertia and have flight speeds comparable to birds and the larger insects. Such craft traverse the lower levels of the atmospheric boundary layer (ABL) which is a significantly different environment than that experienced by larger manned aircraft, which spend the majority of their time in relatively clean air and fly at speeds significantly higher than typical wind speeds in the ABL. Here a new series of measurements dedicated to understanding spatial and temporal velocity fields that MAVs experience are presented. Atmospheric wind measurements were taken by sampling four multi-hole dynamic pressure probes spanned perpendicular to the oncoming wind at spans of between 0·014m and up to 0·45m. It was noted that the variation of both longitudinal velocity and flow pitch angle against spacing followed a fractional power law and as such large variations were present even for the smallest inter-probe separations. This effect is thought to explain the increasing piloting difficulties experienced in maintaining good roll control for decreasing scales of craft.

Information

Type
Research Article
Information
The Aeronautical Journal , Volume 115 , Issue 1173 , November 2011, pp. 693 - 701
Copyright
Copyright © Royal Aeronautical Society 2011 

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