Quote:
Originally Posted by aerohead
I found what I was thinking about.It was drawn over Mair's boat tail 'template',not the 'Template.'
Mair's wind tunnel model,if the rectilinear flow portion is removed,and only nose and boat tail combined,forms a 'template' with a fineness ratio of 2.52:1.Very similar to the 'Template.'
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To duplicate a 'Template'esgue form :
*drop 3.35-H from max camber point and revolve a line for 12.5-degrees,stop.
*drop to 5.294-H and revolve 12-degrees,stop.
*drop to 6.588-H and revolve out 7-degrees,stop.
*drop to 7.96-H and revolve until you strike the ground plane.
This image is very similar to the 'Template' and shaves a little length off Mair's overall length,as his 'template' has a constant 22-degree line of convergence once that angle is achieved.
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As to the 'Template',it is modeled from 'Streamlined body l/D=2,5,Cd 0.04,which appears in Table 2.1 Drag coefficients for different bodies-----------,Hucho,2nd Edition,Page 61.
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The drag curve for Streamline bodies of revolution is asymptotic at around L/D= 2.1 but the 2.5:1 is the 'shortest' body which just fulfills Mair's 22-degree maximum boat tail slope angle for protecting boundary layer attachment.Rolf Buchheim thought 23-degrees would be the limit.I'm just playin' safe with 22.
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Phil,
I took your dimensions from above and worked them with a 2D CAD program and here's what came out...
The shape does not look right, and does not match the "template" very well.
Any comments?
Jim