Quote:
Originally Posted by Otto
The nose and pod shape in a modern sailplane is essentially a body revolution, and you are, in effect, saying that nose shape makes little or no difference.
I respectfully disagree. So do aerodynamicists such as Hucho, Hoerner, Carmichael, Lopresti, all the Germans who design modern sailplanes, NASA guys I talked with years ago, and mathematical modelers such as Zedan. Their research and published results show significant improvement of nose shapes over the years. That is why your DG1000 or an ASW22 noses look like they do and not like your Cardinal.
But, to prove your point, I double dog dare you to saw off the DG1000 nose and bolt on a Cardinal nose sans propeller, and see how she flies.
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Well, in aerodynamics 101, we learned that nose shape is not as critical, in subsonic flow, as, say, the shape of the tail. The classic rain drop comes to mind. Please don't get me wrong. I know it makes a difference. In the case of the cardinal and many other aircraft, Lopresti (who is right up the road, BTW) reduces cooling drag and increases manifold pressure to get the speed. The shape plays a very, very small role on such a slow aircraft as the cardinal. The manufacturers got it fairly close to begin with.
The drag curve on the gliders is beyond belief at design speeds. They truly are works of art. However, when speeds increase, just like any vehicle, the drag increases to the point where terminal velocity is reached.
My point remains, cooling drag is important. Nose shape is less important and tail shape is very important. I don't, for instance, believe that drag can be cut by as much as 30% with a casual re-shape of the 944's nose. More like a couple of percent or less. But, I could be proven wrong, and have been before.