Quote:
Originally Posted by NeilBlanchard
I think the Cd 0.095 was for the blue model with the covered wheels:
It is quite a bit different than the Boxfish diesel prototype. It has a protruding nose (similar to the fish itself) and the rear fascia is significantly smaller than the Boxfish. It has wheels, with very large strakes and very large skirts. It has no cooling tract, and the underside is entirely smooth and it rises toward the rear.
Here's a bunch of screen captures from a video that Mercedes had made, showing the transition between the blue model to the Boxfish (so the color is also morphed) - start here and then use the arrows on the left side:
Mercedes Bionic/Boxfish Clay Model Photo by NeilBlanchard | Photobucket
By the way, this blue model is the starting point I used when designing my CarBEN EV5. |
It's a beautiful car.And they've done so much of the right thing.I just can't get my head around the Cd.
Buchheim did some similar studies at Volkswagen in 1981 and couldn't get below Cd 0.14,even with a complete boat tail on the 'flow' body.
The transom area seems too large for which to achieve a 'phantom' tail.
The 1987 Renault Vesta II has a better windshield and scores only Cd 0.186.
If they're basing the streamlining on plan-view,then they'd be relying more on 2-D sections which cannot tolerate 'Kamm-form' truncation and maintain any semblance of their Cd.
The 1987 GM Sunraycer with full tail and complete wheel fairings got to Cd 0.089 and Cd 0.125 without them in actual race trim.
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It would be nice to know the scale of the model and the tunnel wind speed.
GM models in the Cal Tech model tunnel always indicated Cds far lower than their full-scale counterparts.It would be nice to have more data.
My gut feeling is that,in production trim,with Hucho's 2% drag cooling system,and features drag,that she'd come in at around Cd 0.15-16.
We may never know.
Thanks for the Cornucopia of images! You've invested a fortune on 'Carben',I like to think you'll be delighted at the Watt-meter after 'top-offs' when she's rollin'.
