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Perkins, E. W.

Publications and source records attributed to Perkins, E. W..

Data base for the prediction of inlet external drag

Results are presented from a study to define and evaluate the data base for predicting an airframe/propulsion system interference effect shown to be of considerable importance, inlet external drag. The study is focused on supersonic tactical aircraft with highly integrated jet propulsion systems, although some information is included for supersonic strategic aircraft and for transport aircraft designed for high subsonic or low supersonic cruise. The data base for inlet external drag is considered to consist of the theoretical and empirical prediction methods as well as the experimental data identified in an extensive literature search. The state of the art in the subsonic and transonic speed regimes is evaluated. The experimental data base is organized and presented in a series of tables in which the test article, the quantities measured and the ranges of test conditions covered are described for each set of data; in this way, the breadth of coverage and gaps in the existing experimental data are evident. Prediction methods are categorized by method of solution, type of inlet and speed range to which they apply, major features are given, and their accuracy is assessed by means of comparison to experimental data.

Mcmillan, O. J.↗

Evaluation of methods for prediction of propulsion system drag

The results of a study directed toward compilation of a theoretical and experimental data base covering inlet/airframe and nozzle/afterbody integration are described, with the major emphasis on the evaluation of the adequacy for preliminary design purposes of the data base for afterbody/propulsion system interference effects. Prediction methods that exist for afterbody/airframe interference effects are evaluated with respect to the requirements of breadth, ease of application and accuracy that are important for preliminary design.

Kuhn, G. D.↗

Flow Over Inclined Bodies

It has been shown that the circumferential pressure distributions for the inclined body and circular cylinder deviate from their respective theoretical inviscid distributions on the lee or downstream side in the same manner. With the aid of visual flow techniques, it has been shown that there is a shedding of vortices within the crossflow field of the inclined body. It has also been found that the vortex configuration depoends to a large extent on the shape of the nose of the body. To illustrate this, vapor screen pictures were made and results are discussed.

Perkins, E. W.↗