The Experimental Determination of the Subsonic Aerodynamic Characteristics of an Ogive-Cylinder Body Including a Comparison with Theoretical Estimates: Volume 1

TLDR: In this article, the authors present the results obtained from two series of wind tunnel tests made on an ogive cylinder body of 6:1 fineness ratio in the CoA 8ft x 6ft Low Speed Wind Tunnel.

Abstract: This report presents the results obtained from two series of wind tunnel tests made on an ogive cylinder body of 6:1 fineness ratio in the CoA 8ft x 6ft Low Speed Wind Tunnel. The distribution of pressure on the body was measured over an incidence range of -1 to 10 degrees. The local loading distributions were then obtained by integration of the pressure coefficients; further integration yielded the overall normal force and pitching moment coefficients and hence the centre of pressure position. The results showed that the aerodynamic characteristics were very sensitive to conditions in the base region and that unexpectedly large loadings were present over the last 10% of the body length. There are indications that the bluff asymmetric model support system may be the source of some additional interference effects at the higher incidences, even though it is some 3.7 body diameters downstream of the base. The experimental results have been compared with theoretical estimates obtained by an inviscid ring source method of estimation for axisymmetrical bodies. The theory overestimated the loadings of the ogival nose and under estimated the loadings over the parallel afterbody; in particular the large loadings over the rear of the afterbody were not predicted. The agreement between theory and experiment does not worsen appreciably at the higher incidences as would be expected because of the presence of flow separations. The theoretical results are very sensitive to the base closure assumed, thus it may be possible to achieve closer agreement by suitably altering the closure. Starting in 1946 as the College of Aeronautics, the Cranfield Institute of Technology was granted university status in 1969. In 1993 it changed its name to Cranfield University.