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Old 01-26-2013, 04:56 PM   #445 (permalink)
aerohead
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crosswind stability

Quote:
Originally Posted by hotrodfeguy View Post
This all makes a ton of sense, and I will give you the wind tunnel it would be money in the bank. All of your data is spot on gentlemen !!! But in real world how much is to much? My point is this, lets say your doing 55 and have a 30MPH side wind. It kinda goes to $hit, the long side, boat tail then becomes a negitive impact on areo. Not trying to be a killjoy. Just that I see some holes in some of this. Why double the side area or even at 25% of the car to gain, front to back areo? cause when you introduce a side wind it then becomes more area for drag. look at the car form angles like a diamond if you will, It should not be areo view from just one angle. wind soes not blow form one direction.

On my Driver metro I was going to do a kamback with no sides like a naked edged Kamback to get data then put sides on it to see if I have a real issue here with sidewind or not. I know the more improvements I have made(flat hubcaps, mirroe delete passenger side, wheel well covers, grill block, front air dam) the more the car tends to get shoved off the road by cross wind. And at the last few pages thats where this 22* may be affected, In my humble opinion it should be more agressive to cheat or be more universal to cross wind. I know there is a perfect forula for front back, but I am saying maybe in daily winds it should be more general purpose?

Maybe I am all out in left field. I could be totally wrong.
Your concern for crosswind stability is something which has attracted attention since the 1920s.
Depending upon the position of a cars center of gravity,and center of pressure,gusts and crosswinds could destabilize a car at speed.
Professor Kamm was obsessed with stability,and his last project,around 1966,was with a DKW sedan which he modified to a K-form roofline.Kamm added his signature dual,split-fin stabilizers (Egyptian round-hulled sailing ships used these 'steering-rudders' 4,500 years ago) to guarantee crosswind stability.
Ten years after Kamm's DKW,Professor Morelli determined that Jaray's downward sloping nose,rounded fenders,and Von Mises' reflexed-camber tail could easily mitigate any crosswind funny business.
General Motors Research Labs ascertained that in the United States,we experience an annual mean-averaged 7-mph crosswind condition during driving.
On My trip to Bonneville last September,I drove through a storm front in the Texas panhandle which killed a family of five.I maintained 70 mph through 50 mph crosswind unabated until I got into Santa Rosa ,New Mexico that night.Sure,at times it was 'busy',but at no time did I feel endangered.No one else kept up with me.
My opinion is that a boat tail is zero liability.
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