For low aerodynamic drag, a long tail with attached flow is better than a Kamm tail. Here's the latest tech information from a new SAE engineering paper. My two books - www.amazon.com/Modifying-Aero... and www.amazon.com/Car-Aerodynami...
Thank you so much for his wonderfully clear explanation. I've been reading up on aerodynamics the last few days, and as my general understanding increased, so my understanding of the Kamm tail decreased. Thanks to you it all makes sense.
What I think of as the "modern" iteration of Kamm's tail started, I believe, in the early to mid Sixties on racing cars like the Ferrari 250 GTO, the Aston Martin DP214 and DP215, the Shelby Cobra "Daytona" coupe, etc. They adopted a modified version of the Kamm tail for solid aerodynamic and packaging reasons, it being a good compromise for those cars in terms of weight, length and drag performance. Since it worked well in that context it was also adopted by car stylists designing
Thank you for sharing this. Currently, the use of Kamm tail virtual foils are all the rage in aerodynamic bicycle frame design, a departure from more traditional NACA airfoils from about ten years ago. The problem is, nowadays manufacturers and pro athletes don’t make their aerodynamic testing a available to the public, they just make marketing claims about their bikes. It’s nice to know that there have been studies done on the actual effectiveness of the kamm tail airfoils.
The magic of the Kam tail is in the balance between the drag coefficient and lugging around an extra hundred kilograms or more or awkward sheet metal that you cannot possibly see to avoid backing into things.
Julian. I was looking at some images of the old Shelby Daytona coupe. The Kamm tail on it is concave. with sharp edges. Would the air swirl more there? or would the sharp edges flow together off the back of the tail do you think. Some of them had Wings. so don't count those.
I had a Kamm tail VW......it was a slug. I don't think Kamm used Julian's testing techniques. While we're talking about nice rear ends , let's talk about McLaren speed tail .
That extension of the body on the Jaray Design could be helpful along with modern diffusers? I mean, when Kamm proposed that it did nothing, it was a time when undersides where pretty much ignored when it comes to aerodynamics. With our modern conception of the play of the underside when it comes to drag, couldn't we use that tail as benefit to lower drag?
No Magic? but the proof exists. Look at the Mini Jem for example. This little cars aerodynamic design incorporates a Kamm tail. It was tested and found to be stable up to 170 Mph in a aeronautical wind tunnel even though it could never achieve this speed with its Mini mechanicals.
