The aerodynamics of revolving wings II. Propeller force coefficients from mayfly to quail

Abstract

SUMMARYHigh force coefficients, similar to those observed for revolving model hawkmoth wings in the accompanying paper (for which steady leading-edge vortices are directly observed), are apparent for revolving model (mayfly,bumblebee and quail) and real (quail) animal wings ranging in Reynolds number(Re) from 1100 to 26000. Results for bumblebee and hawkmoth wings agree with those published previously for Drosophila(Re≈200). The effect of aspect ratio is also tested with planforms based on hawkmoth wings adjusted to aspect ratios ranging from 4.53 to 15.84 and is shown to be relatively minor, especially at angles of incidence below 50°.The normal force relationship introduced in the accompanying paper is supported for wings over a large range of aspect ratios in both `early' and`steady' conditions; local induced velocities appear not to affect the relationship.