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Originally Posted by kach22i
Thank you for doing this research, I trust you enjoyed it a bit. I too like doing research, an obsession or a treasure hunt as it were.
At one time in the last decade the Aerotemplate has been altered slightly as I recall.
One of the changes was elongation of the Cod's head.
If anyone can refresh my memory of why this was done and to what benefit, it would be appreciated.
It gets to the point of what's ahead of the "0" mark having an affect on Cd.
I'm imagining an easing in of pressurizing the air for attachment is better than a blunt face with a radius edge, but it may also be splitting hairs if the actual real life advantages are crosswinds and not numbers in a static section/condition.
I trust Aerohead's company comes first, I'm just getting over a sinus infection and need a low stress distraction while I take some time off work to get better.
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* The premise for the series of 'templates' was to emphasize the importance of the aft-body architecture, in relation to flow separation and pressure drag.
* And since the mid- 1980s, all mass-produced passenger cars had already done Hucho et al.'s forebody 'optimizations', I gave no emphasis to the forebodies of any of the 'templates.'
* Also, from fluid mechanics, it's been demonstrated that, for 'subsonic', non-compressible flow, a convex- hemispherical nose is perfectly acceptable to guarantee fully-attached forebody flow. So I de-lengthened the traditional cod's head of a streamline body-of-revolution-based half-body, figuring that it wouldn't impact flow, would reduce overall body length, save weight; and from BELL and Hughes Helicopter bubble canopy technology, provide perfect optical quality to the front screen ( I was allowed to sit in some of these helicopters at Oshkosh, Wisconsin's annual EAA Fly-In, and they give the pilot 'perfect' forward vision ).
If you have D.M. Waters' 1969 research on a rectangular block, you'll notice that he achieved a drag minimum of Cd 0.126 with all edges rounded to 39% of the square-root of frontal area dimension, close to dimensionless 'half-round.'
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As to angles in the aft-body of the different 'templates', as I recognized variations for the L/D= 2.5:1 streamline body of revolution, and their half-body counterparts, I wanted to present them, as they were matching 'high-cube' and 'low-cube' auto bodies, and those with vehicles matching the different profiles, they'd have a ready-made 'solution' for elongation of the roofline. Our only passport into 'Low-Drag Nation.'
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I do enjoy the evolution in fluid mechanics, and re-visiting the 'GIANTS' who's shoulders we get to stand on.
