The effect of forward speed on the inlet flow distribution and performance of a lifting fan installed in a wing

Abstract

Five-tube yawmeter traverses immediately up and downstream of the fan reveal the flow maldistributions due to forward speed. These are removed by a deep duct or an inlet cascade, which turn the air into the axial direction. Non-uniformity of the exit static pressure, however, does not affect the flow distribution. Since forward speed reduces the pressure rise required, stalling of the fan blades appears not to be a great danger except at very high forward speeds, or when a deflected exit cascade is fitted.