Editorial: Watch Out For High-Flying IndyCars

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In 2010, Mike Conway made contact with Ryan Hunter-Reay, and went airborne into the catch fence at IMS. He will not ever race at Indy again, according to him. He flew while facing forward. The air went under the front of the car, and lifted him. Same with Kenny Brack, and many others, including Dan Wheldon. All of these resulted in serious injuries, and yes, even the tragic death of one of the most charismatic men I have ever had the privelege to know.

So here we sit, just days away from the 2015 Indianapolis 500, and we have flying IndyCars once again.

So why are they flying? I have my theories, and let me preface this by saying, I am no engineer. Hell, I only have an associates degree in business science! But, this is my theory.

An airplane has a wing shape that allows air to flow freely over it, “cutting” the wind. However, it is also designed for “lift”. It causes the plane, when proper adjustments are made, via flaps, to lift into the air, nose first. The front wing’s on the older Dallara IndyCars had a very similar shape for their “cutting” benefits, but downforce was created by the floor of the chassis, and other “wing-like” elements. So, when one of these chassis were lifted off the ground, from the front, they took off, like an airplane.

On the new chassis, again, the “drag coefficient” is very low, which allows these cars to reach such high speeds so efficiently, but downforce creates a counter punch to this coefficiency, causing the cars to stick to the pavement at speeds. There is still the wing shape, and the body, which creates this downforce.

BUT, when the cars get turned around, there are these GIANT tire sized holes which flow into a backwards wing shaped aero package, and this IN MY OPINION, is where we are seeing the take off. I noticed in yesterdays crash with James Hinchcliffe, that ONE of the rear “tire covers” was destroyed in the initial collision with the wall, and James’ car didn’t try to “take off” as Ed, Josef’s, and Helio’s cars did. BUT, what did happen was the ONE side that had the tire cover on it, once the car did turn around, was lifted off of the ground. This is why I see this as the problem.

In this video you can see how this shape can contribute to lift.

Now look at the back of an IndyCar

Honda (click to view)
Chevy (click to view)

See the similarities?

So, in my uneducated opinion, THIS is why these cars take off when going backwards.  These holes are acting as “scoops” for the air that is now freely flowing BACKWARDS against what was being used for downforce, and creating “upforce”.  Hence, flying IndyCars.

Thoughts? Feel free to share them with me on Twitter at @open_wheels and @tonytellez

*image borrowed without permission from AP.

Tony Tellez

One Comment

  1. I agree completely with your analysis. Another question, at with HCN, Carpenter, and Newgarden is what caused the car to get loose initially. All three were in the groove and there was no apparent driver error. I also am no engineer but I’ve been around racing for a long while. I have 2 possible theories. First there may be a basic design flaw in the Chevy aero kit which causes the rear wing to stall under yaw and pitch? This would account for the sudden full loose condition. The second theory could apply to both aero kits. Is the massive downforce overpowering the suspension, wheel bearings or tire side walls? There has been little or no discussion or the causes of the spins, everybody is focused.on the flying. A race car needs to be designed “holistically”. These cars were designed a separate components. There is more to aero design than simply hanging new components on a generic spec chassis.

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