Abstract:
(a) Reasons for enquiry (l) The Momentum Theory of R. E. Fronde leads to equations which require some modification when the airscrew is working in a tunnel of dimensions comparable with the diameter of the screw. (2) Some correction to the speed of the air in a wind channel must be made to obtain the equivalent speed of advance of the airscrew in free air. (b) Conclusions - (l) Formu1ae for the thrust-momentum relation, inflow-outflow ratio and contraction ratio of the slipstream are deduced. (2) A method of correcting the speed of advance for the effect of channel constraint of flow is obtained based upon the Momentum Theory, which may probably be relied upon so long as the correction required is reasonably small.
