Showing papers by "Vaughn College of Aeronautics and Technology published in 1986"
TL;DR: In this article, the results from a series of wind tunnel experiments are presented, intended to measure dynamic forces and moments on simplified commercial vehicle type models rotating about their vertical center line axis in smooth, uniform flow.
37 citations
TL;DR: In this paper, the formation and development of spiral vortex flow over a swept-back wing was studied using the surface oil-flow visualisation technique supplemented by pressure distribution measurements in certain cases.
Abstract: An experimental investigation has been performed to study the formation and development of spiral vortex flow over a swept-back wing. An aerofoil section with three alternative leading edge shapes was tested at sweep angles ranging from 0° to 56° for unit Reynolds numbers of 1 × 106/m and 2 × 106/m. The principal diagnostic tool was the surface oil-flow visualisation technique supplemented by pressure distribution measurements in certain cases. No spiral vortex flow was observed for sweep angles of 0° and 15° but at higher sweep angles the oil-flows indicated that there were three different mechanisms for the formation of spiral vortices. The angle of incidence at the onset of vortex flow, and the mechanism responsible for its formation, were found to depend upon the sweep angle, the leading edge shape and the Reynolds number. It was also noted that the larger the leading edge radius the greater the dependence upon Reynolds number. However, comparison with other work suggests that Reynolds number, incidence and sweep angle alone are insufficient to determine the type of spiral vortex flow occurring on a given wing.
27 citations
TL;DR: In this paper, the authors compare the take-off distance of a landplane and a flying boat and show that the latter is inversely proportional to the square of the thrust/weight ratio to the power of the landplane.
Abstract: It is useful to have available simple prediction formulae for preliminary design work. In the case of landplane take-off such formulae exist, being expressed only in terms of a few major parameters. The flying boat situation is more complex due to the much greater and more variable total drag. By making appropriate assumptions an equivalent formula for flying boat take-off has been derived. Comparison of typical cases of the landplane and flying boat shows that whereas the take-off distance of the former is approximately inversely proportional to thrust/weight ratio to the power of 1·35, in the case of a flying boat it is inversely proportional to the square of thrust/weight ratio.
1 citations
TL;DR: The variation of the crack stress intensity factor for two cracks growing from one hole only in an array of holes in an isotropic material under uni-axial tension has been studied in this article.
Abstract: The variation of the Crack Stress Intensity Factor (SIF), for two cracks growing from one hole only in an array of holes in an isotropic material under uni-axial tension has been studied. The effect of the fastener hole ahead of the growing crack was found to give an increase in the SIF only when the crack was within about one and a half diameters of the approached hole edge, compared with the level predicted by considering a single central hole in a plate. An equation suitable for inclusion in a crack growth program has been derived from the research results.