IN approaching any problem in Aerodynamics the student, and the severely practical engineer, whose academic knowledge may be limited, are too frequently confronted with two difficulties The first of these is that though the literature on the subject is extensive, yet the information sought usually has to be collected from a number of sources and the second is that when found the information is frequently presented in such a manner as to be of little immediate practical value without a certain amount of simplification

The object of this paper is to collate and present in an immediately useful form the information contained in parts of the following publications