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Old 02-02-2010, 06:18 PM   #22 (permalink)
aerohead
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Quote:
Originally Posted by Bearleener View Post
diesel_john, what does your stepped tail look like? How is it fastened/reinforced? Thanks!

Has anyone thought about a retractable Kammback? Sure would be nice if it would fold together at low speeds, reducing vehicle length for easier parking and making it slightly more street-legal.

One possibility would be, say, 3 panels that fold out at the top and sides, perhaps deployed with a pull string arrangement through eyelets at the corners.

Or how about a clear plastic, inflatable, conical bag (something like those temporary bouys used for sailboat regattas), which would roll up into a little box when parked? Maybe you could even use the low-pressure area back there at speed to inflate it. Or exhaust gases at the tailpipe: pump directly to inflate, use a venturi with side tap to create vacuum to deflate.
In the U.S.,the DOT allows length statutes to be violated by 48-inches if for fuel economy.
The inflated conical bag has already been patented by a fella in Lubbock,Texas,which is inflated by ram-pressure of the moving rig.
If you can get a look at Hucho's "Aerodynamics of Road Vehicles",there is a depiction of the best inflated(extensible) tail I've seen yet,from 1930s Germany.I believe the design is by Koenig von Fachsenfeld/Kamm.
A very crude fan-inflated envelope helped my pickup to see over 30-mpg at 65-mph,with air conditioning on.
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