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Wind tunnel experiments to assess the effect of back-mounted radio transmitters on bird body drag

H.H. Obrecht·C.J. Pennycuick·M.R. Fuller
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Abstract

The aerodynamic drag of bird bodies was measured in a wind tunnel, with and without back-mounted dummy radio transmitters. Flight performance estimates indicate that the drag of a large transmitter can cause a substantial reduction of a migrant’s range, that is, the distance it can cover in non-stop flight. The drag of the transmitter can be reduced by arranging the components in an elongated shape, so minimizing the frontal area. The addition of a rounded fairing to the front end, and a pointed fairing behind, was found to reduce the drag of the transmitter by about one-third, as compared with an unfaired rectangular box.

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H.H. Obrecht, C.J. Pennycuick, M.R. Fuller. 1988. Wind tunnel experiments to assess the effect of back-mounted radio transmitters on bird body drag. https://doi.org/10.1242/jeb.135.1.265

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