PCA SDR

This is supposed to be a real stunt. What do you guys think?
http://www.dailymotion.com/video/xc1nc5 ... unnel_auto

Piece of cake. A simple 1G roll. You just gotta get the math right and hit your marks.

Not to diminish a very cool commercial but haven't stunt / circus drivers have been doing Corkscrew rolls for some time? I could be wrong. Anyway NOT at the speed which this is run, nor in that expensive of a car. But this does bring up a thing I heard in a documentary on Formula one cars and wondered about. The statement was "At 100 mph this car develops enough down force to drive inverted on an upside down roadway." Of course my first thought was..."ok...then why hasn't some adrenaline junky done it yet? Would it work or is it only viable on paper?

It could be real, but there are two things I noticed. First, like you mentioned, this car doesn't have wings for any appreciable amount of downforce. Second the walls of the tunnel are verticle and square to the roadway when you first look into the tunnel. It's not like there is a smooth transition from the roadway to the walls, like if it was a pipe.
It seems to me that if this was really pulled off by Mercedes there would have been a lot more publicity about it.

If you look a the video carefully, you'll see that it has built up entrance and exit ramps from the road to the sides of the tunnel. I don't know if they really pulled it off, but enough speed at the right angle and it's physically possible. We used to run Hot Wheels off of the roof of our house and try to get them to do giant loops. The more speed you generated, the larger the loop could be.... up to a point.

gocart wrote:It could be real, but there are two things I noticed. First, like you mentioned, this car doesn't have wings for any appreciable amount of downforce. Second the walls of the tunnel are verticle and square to the roadway when you first look into the tunnel. It's not like there is a smooth transition from the roadway to the walls, like if it was a pipe.
It seems to me that if this was really pulled off by Mercedes there would have been a lot more publicity about it.

Frame at 2:09 tells the story. You can see that it is a pipe (curved ceiling), see the in ramp and out ramp, and where they removed some of the lighting rails for a smooth even surface. All you need is enough centrifugal force to overcome gravity. No aerodynamic downforce needed. In China they do these kind of stunts on motorcycles. Cool way to sell cars though.

You know, I tried something like this in my 944 in a drainage ditch.....it didn't end well.

Be sure to watch upcoming Top Gear show where they "attempt" this !!