Found it! I thought I was making this up.
Those massive vortexes apparently aren't caused by the air exiting the front wheelwell, but by the rear fenders. Or not. At least in this simulation.
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I have my doubts about the fenders causing lift and especially if they do, that those vents are a cure.
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I'm more concerned with how you attenutate those in-rolling vortexes.
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That raised hood on "The Fix" made me laugh.
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Maybe it's a gauge cluster? I was more amused by the 'speed lines' and colored arrows that disappear with the 'fix'.
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Originally Posted by aerohead
The Beetle produces 57-lbs front lift at 100 km/hr (62 mph) and 100-lbs front lift at 100 mph.
The Beetle produces no rear lift.I'm at a complete loss as to why they show rear lift.
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http://http://www.shoptalkforums.com...92902#p1092902
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Hi Slow1200,
I referred to the Sports Car Graphic article data, but only as their data.
Fisher cites in his "Stability and the Beetle" chapter (pg 141) of his original "How to Hotrod VW Engines" 68lbs of rear end lift on the Beetle body at 75mph, extrapolated to 136lbs at 100mph.
The numbers are from Paul Lamar, introduced by Fisher as a noted aerodynamic expert from Manhattan Beach CA, and I do not doubt his findings. Sports Car Graphic was one publication that used Lamar's information, but I don't know if Lamar had any input in the "Why Would Anyone Buy A VW" Sports Car Graphic article in which zero lift on the Bug rear end was quoted.
I went back and reread the Fisher chapter today, and it appears to be the source of the info that VW slightly raised the front suspension of the Bug (swing axle) to increase front lift and decrease rear lift.
We get all this info from different publications, but in the end it is application on the racetrack that matters. My own experience with aerodynamic extremes is with the 1973 Super Beetle IMSA car we had back in the mid-1970's which we ran at the Talladega Super Speedway for the closed-course speed record for a stock-bodied VW. That means no aerodynamic aids.
And we ran an engine that would have been illegal in IMSA B-Sedan. This was a speed record engine.
Our car could briefly touch 130mph+ on the straights, but didn't have the power to stick in the banking more than a third of the way up. And it was a handful. We had lots of rear lift that translated into the tail losing adhesion and trying to pass the front, so we were "crabbing" sideways at times.
We had a full pan but had cut away all the interior bodywork and tried to vent out air pressure filling the car's interior with holes venting to low pressure, etc.
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I've got the stance down, 3 1/2" front clearance excepting the tow hook. I'm watching the PolyMetal scraps at the local recyclers; I don't want to use Coroplast (there's 10 full 4x8 sheets of that). So, a splitter/air dam, Nylon brushes about 2" deep behind the front wheels and under the running boards.
Remember the 'cheese grater'? It's a little decorative piece of tin that fits on the chrome tailpipes. I want a little baby diffuser that wraps the exhaust up behind the back bumper.
Edit: CFECO -- Sorry about what's happened to your thread. When I was a teenager my cousins on the southern Oregon coast told me about someone who topped a rise into a 100mph headwind and wound up on their back in the underbrush.