Stromius

Congrats...this has been another fun thread to follow your team!

928mac

Very nice how the tail brought you back and a very nice job turning out of it to stop it from going around when it was coming back.
The reflex was right from what I see and you walk away to race another day.

Nice job carl,
more cow bell, more cow bell, MOre Wing

atb

How is it that Carl gets a 90 degree look at the scenery and pulls straight without getting airborne? Definitely a thumbs up to the design work to keep the car on the ground.

Carl Fausett

The trip fences on the roof are there to disturb the air flow over the top and prevent lift should the car become sideways, and the rear diffuser with ground effects are there to help keep it down. Then there's the 1400 lbs of ballast hung under the car at the lowest possible point.

Even with all of that - I was certain that the snap 2nd spin (going clockwise) would bring me ***-front into the direction of travel. I was also pretty certain that we would pack air under the car at that point and achieve lift-off. Basically, the rear diffuser and rake of the car would be perfect when travelling backwards at 200 MPH to just about guarantee flight.

So I figured I had one chance to pull that chute as I swung thru from L to R to stop the second spin.

Photos below of the rear diffuser and the rooftop trip fences.

Fastest928

George, that average is staggering!,

Bill Ball

Holy Mother of God! Carl, that is far too close to disaster for me. I used to knee-drag the local canyons on my rice rocket. One time I came blasting around a corner only to be confronted by the front bumper of an oncoming car over the centerline. I followed Keith Code's advice and looked away from the bumper, instead focusing on where I wanted to go. I missed smacking that car head-on by a hair. That was the end of my knee-dragging exploits. You can only roll the dice so many times before it comes up craps.

And that new SSCC record AVERAGE must be a typo.

AO

Wow Carl. That's downright scary! Missed you at the Packer Party in Green Bay.

jorj7

Carl,

That looks like a very hair raising situation. I'm glad it all worked out. I would definitely reconsider
making high speed runs in the wind...

inactiveuser1

Carl,nice driving and save!
See the rpm now in post 374
5720 RPM at 216 MPH

Carl Fausett

Right. 5720 rpm at 216.6 MPH, so I would say at 213 I was just under that.

This engine comes into its HP band best above 6000 rpm, so we haven't even been there yet. Got to get the traction first, I've got the muscle.

Keep in mind that in land speed racing, HP is valued more than Torque.

FredR

Carl,

That video is truly mind blowing. I must presume that going sideways at that speed must have converted you into a hovercraft with little to no bite on the tires otherwise you would have dug in and flipped over.

Thank goodness you are safe and able to tell the tale. Crikes- I think I need to change my shorts just from watching the video!

Take care of yourself

Fred

Mother

What size tires are you running and is it possible to go taller and do you think by not having the rear tires partially covered over would cut down on tire lift? You also said that that you are having aero tested as a suggestion bring some spare sheet aluminum to cover with speed tape to the car and check for readings. Sorry just being a busy body.

Carl Fausett

There are no changes allowed to the car behind the cowl except the very few they allow in this class (you are allowed to take your side-view mirrors off, for example). Side skirts on the rear fenders would certainly help, but they are not allowed.

My tires are 28.4" in diameter, and at 6700 rpm, in a perfect world with perfect traction between tire and the ground, would produce revolutions to equal 253.7 MPH. Aerodynamic resistance must be subtracted from that number.

Glenn Evans

Are you permitted to run a wing rather than the (or together with a) rear spoiler?

Glenn Evans

If your Cd is 0.30, frontal area 22ft^2 and density altitude 6000ft, you would require just over 700bhp at the wheels to do 253.7mph, on road tyres and a hard surface. The rolling resistance of the Bonneville tyres will be lower, but the salt will absorb power as it deforms under the tyres; how much would depend on its condition. That 700-odd bhp comprises about 640 to overcome aero drag and 65 for rolling resistance.

By comparison, at 240mph, you would require 520 and 60 bhp respectively. If your power output decreases in proportion to density altitude, you would still have about 640bhp at 6200rpm.

Of course, the Cd will increase with the co-efficient of lift (downforce), and so will the rolling resistance, so the required power figures above are lower than you should expect. If you can get enough traction, you should be good for 240 mph but will run out of power before 258.