Excellent info, thank you, its rare to have such hard data to
ponder
keep it coming
Joe :)
Albaugh, Neil wrote:
>List;
>
>At lunch today I had an opportunity to ask John Horsman about the GT-40's
>aerodynamics and he was quite helpful. He had photographs of some of the
>Ford GT-40s and their later variants such as their Gulf Mirage. In a photo
>taken in April 1964 at the trials (practice) at Le Mans, John pointed out
>that the original GT-40 design had a rather high "pointy" nose and a tail
>with no spoiler. It was so unstable that those two cars went off into the
>weeds on the fast 3.5 mile long Mulsanne Straight (sounds like Maxton).
>
>A spoiler was added and it helped but another photo taken of that car at
>high speed showed the nose lifted by what looked like about 4 to 5 inches! A
>new nose was designed and it helped, but the early GT-40s suffered from the
>FIA regulation that required a full- width windshield and that could have
>made the lift problem even worse (my opinion).
>
>I found some data that may illustrate the point:
>
>1967 Ford GT40 MkIV Lift:
>213 lbs. @ 180 mph, with 554 lbs. of drag
>263 lbs. @ 200 mph, with 648 lbs. of drag
>318 lbs. @ 220 mph, with 828 lbs. of drag
>
>
>1966 Ford GT40 MkII Lift:
>144 lbs. @ 180 mph, with 756 lbs. of drag
>177 lbs. @ 200 mph, with 933 lbs. of drag
>
>Compare this with a modern street- driven sports car:
>
>2000 Porsche 911 Lift:
>600 lbs. @ 150 mph
>Aero. Balance @ 150 mph:
>F: 228 lbs.
>R: 372 lbs.
>
>These all generate LIFT-- not a good thing! Compare those with a much later
>race car:
>
>2001 Bentley EXP Speed 8 LMGTP
>High downforce configuration: Downforce:
>3094 lbs. @ 150 mph
>5500 lbs. @ 200 mph
>Low downforce configuration: Downforce:
>2200 lbs. @ 150 mph, with 600 lbs. of drag
>3911 lbs. @ 200 mph, with 1066 lbs. of drag
>Lift-to-drag ratio: 3.7:1
>
>Most modern competition cars have more BHP than they can deliver to the road
>so they trade off loss of horsepower (drag) for the ability to put the power
>onto the road (downforce).
>
>I realize that GT cars don't run under the same rules as SCTA but I wanted
>to pass this info along for what it's worth. I'll save the wide tire /
>narrow tire controversy for another time.
>
>Regards, Neil Tucson, AZ -- boring everyone to tears by now......
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/// what is needed. It isn't that difficult, folks.
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