| Themes > Science > Physics > Fluid Dynamics > Flying the flag for fluid dynamics > Aerodynamics > Selected Topics of Model Aerodynamics > Aerodynamics of Spar&Rib Structures > Conclusions |
It is difficult to draw general conclusions from these results. It looks like the sagging of the cover material between the ribs seems to have a beneficial effect at Reynolds numbers of 100'000 and below. At higher Reynolds numbers the drag increases over a wide range of lift coefficients; I would not take it for granted, that the drag decrease, which is visible on the MH 42 at low lift coefficients, can be observed on other airfoils. The variation on drag coefficient along the span, as calculated by two dimensional, stripwise analysis, is relatively small. On the one hand, it is questionable, whether such an analysis is justified and whether the results are close to reality, on the other hand the regular structured surface my reduce the spanwise drag and lift variations, which occur on strictly cylindrical wings. Hopefully future investigations will shed a light on these questions. Future experimental investigations should also include local measurements of sound levels and frequencies as well as inflow variations and details about the model quality in spanwise direction. |
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