Quote:
Originally Posted by freebeard
That appears to me to approximate the frontal prolate-ellipsoid to about station 50, with a simple cone from there.
Arranging in order from roundest to pointed-est, I have Schlorwagen, Dymaxion, Mair and then The Template. Rounding off saves overall length. Is there any guidance here?
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What I took away from Mair's work was:
*Be careful about the transition into the curve. As it is depicted,the gentle curvature will protect the fragile boundary layer,preventing separation.
*Once you're to 22-degrees,you can just project that line as far as you like.This construction would require internal bracing to prevent tin-canning as without the ovoid compound-curvature she'd be rubbery.
*Mair's drag curve suggests the decreasing returns you get from extending beyond about 52% of the full tail.
*At this length,a car would have Cd 0.284.
*If you ran an inflated tail section out to 90% you'd have Cd 0.166.
*If you lose the constant-velocity portion of the model,leaving only the nose and tail,you end up with a body of revolution 'template' of L/D= 2.52,very similar to the 'Template,' of Cd 0.04,and Cd 0.08 in ground effect,and around Cd 0.12 as a half-body with skinny wheels.
*This is where I took the 22-degree limit for the 'Template.'
*Hucho's partner,Rolf Buchheim (sp?) allowed 23-degrees as a maximum.