Abstract
The basic equations of lifting surface theory are derived and used to provide methods for the design and evaluation of propellers. For the design calculation, the method requires as data the number of blades and the blade outline and thickness distribution, the wake inflow pattern and advance ratio, and the required thrust together with the shape of the circulation distribution over the blade surface; the method will then yield a value of the torque required, and also the blade pitch angle distribution and the distribution of camber, cavitation number and actual circulation values over the blade surface. For the evaluation calculation, the method requires full details of the propeller and operating conditions, and will yield thrust and torque values and also surface distributions of circulation value and cavitation number.
The treatment includes the case of a pair of contra-rotating propellers, and the similar case of a rotor-stator combination. The method will treat straight or skewed propellers.
The numerical techniques used in the calculations are described. Some information is also given about the KDF9 computer program which was written to carry out the computation. Numerical examples are presented.
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