:
>
>Joe Alexander and Jack Drews both have TR4's with similar but not quite
>identical preparation. Joe's is a roadster. Jack's is raced with the
>windshield and Surrey top which, of course, includes the back window.
>
>Jack's car weighs maybe 150 lb. more and has more frontal area with the
>full windshield.
>
>The performance of these cars is virtually identical -- when we come out
>of a corner together, the cars have virtually equal acceleration and
>terminal speed.
>
>We are both surprised that performance is identical -- wouldn't you
>think that acceleration out of corners would be better with Joe's lower
>weight, and shouldn't he also have a higher top speed, with the lower
>frontal area?
>--
The drag due to the larger frontal area of the hardtop is probably about
equal to the drag caused by turbulence around the open cockpit of the
roadster. If I remember correctly, an MGBGT is slightly faster than a
roadster, even though it has a taller windshield and more weight. Then
again, maybe Jack has hidden a nitrous bottle on his car. :-)
Calvin Krug
bench racer
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