What could have caused this?

[rick_ingram]

The Spuriites have been having discussion as to the possible cause of this Cobra roll-over.

https://video.aol.com/video-detail/vir-cobra-flip/402707078

Watch the red Cobra.

So, how does this happen? Curious to your thoughts.....

 

[tony barnhill]

Well, he was flat out & for some reason downshifted right before the car went perpendicular to the track.

 

[DNK]

I say something on the right rear broke,maybe shifting to high, got it sideways and then it's clean your pants time

 

[GregW]

Right when he skids, the road turns a darker color. Damp road in the turn?

 

[Steve_S]

What I want to know is how a Miata and a old Sentra were right on their tails.

The red Cobra driver wasn't the smoothest I've seen, and it appeared to be a track day rather than a real race. Probably hit the brakes at the wrong moment. Cobras are very tail-happy cars. One went sideways right over the curb at Cars & Coffee when the driver blipped the throttle. See here

Greg, the dark color looks like several years of hard braking to me. I think he just broke too hard.

 

[aeronca65t]

Maybe caused by several problems:

~~Many kit cars are a mix and match of suspension parts from other cars. A key to good handling is to have the roll centers (front and rear) at similar heights. It's my understanding that many kits Cobras that have live rear axles have the roll centers at very different heights. The front RC being below ground level (on both Fox-based and Mustang II-based cars). And the rear RC being roughly in the center of the differential. This makes them pretty tail-happy (the typically high-powered engines put in these cars can add to this oversteer trait at lower speeds, but it's the mis-matched roll centers that cause the real problems when at higher speeds).

I could not tell if this was a live-axle car (I stopped the vid several times to look at the undercarriage), but if it was, this may have contributed.

~~Also ride height. This car was not real low based on views in the early part of the vid. Increased ride height raises CG, increasing chance of roll over.

~~When the car takes the first part of its CCW spin, the right-side suspension is "loaded" and springs on that side compress. It continues to spin CCW so that the left side of the car is "leading"......just as the right-side springs are releasing their load and "pushing" that side up ("helping" the car to roll). Softer shock valves might aggravate this situation. No way of knowing that from the video, of course.

~~When a car spins like this, a driver is told to "put two feet in". This means to floor the brakes and floor the clutch. The reasoning is that the car will act more predictably, continuing in a more or less straight line. This allows other racers to avoid it. If the brakes are not locked down, the car will lurch and grab as it spins causing and unpredictable path...and sometimes "grabbing" in a fashion that can cause a flip.

Did you see how fast that car was on the straight? To my eye, that amount of speed spoils the fun. This is why I much prefer smaller-engined racers. A friend of mine has offered to let me co-drive a really fast endurance racer this year and I'm really hesitant.......105 mph in my Spridget is fast enough!

And as Steve said, this was a street-car, track day event. That Cobra only had one of those tiny, single-side roll bars popular on street Cobras. At that speed, I'd want a full cage.

 

[GregW]

Greg, the dark color looks like several years of hard braking to me. I think he just broke too hard.

There seems to be more than tire tracks on that corner though. The darker pavement doesn't follow the line the cars would take in the turn. There is a road that merges from the right side of frame that lines up with the darkness I'm referring to.

 

[SilentUnicorn]

Pink elephant?

m

 

[bgbassplyr]

I agree with aronca65t, plus the left rear tire looks like it may have caught in the dirt at the pavement interface and the left front tire was not locked down and got enough traction to amplify the rotation. Most of the time, locking all 4 wheels allows the car to continue in one direction. It's the old 'a body in motion' thing.

 

[texas_bugeye]

Look at the color of the track just before the tires leave the ground and the direction the front wheels are facing. car still whants to go in the same direction which is now drivers door upwind I'd say it got some sticky track and dirt loaded the suspension you can see the rubber being left on the track from the drivers side front tire side and control we have liftoff!
He did not stay on the brakes.

 

[William]

I agree with aronca65t, plus the left rear tire looks like it may have caught in the dirt at the pavement interface and the left front tire was not locked down and got enough traction to amplify the rotation. Most of the time, locking all 4 wheels allows the car to continue in one direction. It's the old 'a body in motion' thing.

Indeed it simply looks like the car dug in and over she went.

 

[rick_ingram]

This in from Max Fulton, who originally posted the query to my group...and is somewhat "home-based" at VIR with his race team:


All:

Alas, I'd love to say I actually KNOW the answer to the "flip", but I don't.

It is Turn 14, top of "Rollercoaster" at VIR. It looks daunting as heck from the ground, but barely phases you IN a car.

What it IS, though, is the end of the longest (nearly fastest) straight at VIR. So, *first* real chance for some serious braking.

Along the lines of poorly-sorted or set-up cars, I often wonder if the car simply had a partially sticking front caliper (RH) and it just rotated around the "working" LF, and THEN the forward (now sideways) momentum (AND high C of G) take over and over she goes.....

For those that asked, the "dark" patch is from a repaving job that brings in an extra section ("Patriot Course") from the right. While you can feel the transition in GRIP, you can't really feel it through
the tires. (Read: it's NOT "uneven", etc.)


Oh well.... one balled up Cobra!

M