I lifted this article (below) from a Feb. '74 Car & Driver while doing research on 911's, once, a long time ago...

It's been years since I copied it, but I've never seen anyone since publish this rather simple, yet profound display of why 911's benefit from tails.

Lately it seemed appropriate to dig it out, given all the recent talk of ducktails (Singer, 911 "Sport Classic")

One thing that I disagree with in the article: That ducktail didn't provide "substantial vertical down forces" - it only retards ('spoils') lift generated by the basic 911 profile. Gravity was producing all the down force.

A 964 and early 911 have the same profile.
So, if your tail doesn't deploy at speed, your wheels ARE following that graph's "without rear spoiler" (weight-off-rear-wheels) curve.

Anyone wanna generate a 964 graph?
Enjoy.

Attachment 401421

 

Lonnie,

Thanks for sharing. This is an interesting article.

 

Thanks for that Lonnie. It just goes to prove that messing around with different designs of rear spoilers should always be balanced by a matching "enhancement" to the front as well.

Regards

Dave