How NASA Research could end NASCAR Engine Failures Due to Trash on the Grille

For want of a nail the shoe was lost.
For want of a shoe the horse was lost.
For want of a horse the rider was lost.
For want of a rider the message was lost.
For want of a message the battle was lost.
For want of a battle the kingdom was lost.
And all for the want of a horseshoe nail.

Sometimes something very small ends up making a huge difference.

Last week at Talladega, a stray wrapper stuck on the front of the #2 car ended Brad Keselowski’s Chase chances.

As the Chase started at Chicagoland, the windshield tear-off that landed on Joey Logano’s car affixed itself late enough in the race to actually help him. The tear-off provided additional downforce and allowed him to finish fourth. According to Logano, the engine started blowing up in Turn 3 of the final lap.

“We hit a piece of debris with about five to go… I say ‘piece’, but it was huge. I think it was a tear-off and we got really hot, but the car started handling really good when it was on there” (Quote from NASCAR Wire Service)

But if the tear-off had affixed itself a few laps earlier, Logano might have had the same outcome as Keselowski.

Why Does Trash Always End Up on the Grille?

It’s no coincidence, of course, that trash ends up on the car’s grille. In addition to being a fairly planar surface, it’s the primary place on the car where air goes in. The grille of the car is sort of like a vacuum cleaner: Air rushing through the grille to cool the radiator pulls in whatever happens to be nearby.

And whatever happens to be nearby often ends up being a hot dog wrapper, a plastic bag or a stray piece of tear-off. Something the size of a hot dog wrapper can block air from getting to the radiator. Without air cooling the radiator, the water and oil coursing through the engine have no way to get rid of heat. That heat returns to the engine, making the engine hotter and hotter until a puff of blue-white smoke tells you that the engine is about to go to that great parts-bin in the sky.

bspeed_2016_10_tearoffs_grillediagram

The problem is especially significant at plate tracks because grille openings are already small.

And at Martinsville because there are so many hot-dog wrappers!!

Can We Eliminate the Source of the Problem?

Good luck with that. Tear offs are critical to drivers being able to see. Tear-offs intercept the dirt and track debris that splats on the windshield. When enough crap has accumulated, a pit crew member may be told by the crew chief to remove a tear off at the next pit stop.

Tear offs are very thin – about 4mil, which is a little thicker than a high-quality trash bag or a piece of copy paper. Because the tear-offs are thin and clear (and hard to see) and the crew wears gloves, the team puts tabs on the tear offs so the crew members can see and grab them easily. There may be as many as eight tear offs on a car.

bspeed_2016_10_tearoffs_tabs

 

The problem is that you’re grabbing a piece of thin plastic the size of a windshield by one tab in the corner. Ever tried wrestling Saran Wrap? It rarely does what you want it to. Sometimes the tear-off comes off in pieces. Telling teams to be careful isn’t going to solve the problem. Trust me – they don’t want their tear off wreaking their or another driver’s day.  And it’s not like you could penalize people because (unlike wheels and car parts), there’s no way to identify whose tear-off is stuck to the front of your car.

NASCAR is talking about reducing the number of people allowed to service the car during a pit stop. If you required teams to clean off the windshield using a squeegee and spray bottle, that would slow pit stops down, right? But knowing NASCAR drivers, they would probably just forgo regular cleanings and try to see through the accumulated bugs, rubber and dirt that gets on the windshield.

And the food wrappers and plastic bags are an even bigger source of radiator-blocking problems. Zoos have done away with plastic lids and straws so that they don’t end up in animal enclosures. But I see no way you can eliminate food wrappers and plastic bags from the race track.

So the question is not “how do we keep trash from getting on the grille” because that is going to happen. It’s “How do we deal with the problem once it does get on the grille?”

A Little Help From My Friends?

The traditional way of removing trash from the grille is to get behind another car and allow the vacuum that’s created between the tail of that car and the front of your car to pull the bag off the grille. Essentially, you’re using an even bigger vacuum to remove the trash. But having that works depends on you having a friend in the right place at the right time.

NASA to the Rescue

Luckily for us, NASA’s rocket scientists are working on a solution.

Well, okay, they’re not actually working on it for us. Yes, we have an image of NASA as working on developing satellites for exploring outer space and rovers to explore Mars. But a large number of NASA solutions are often relevant to the many earth-bound problems real people face in everyday life.

One of NASA’s research projects is called the ERA — Environmentally Responsible Aviation — project. The project’s goal is to decrease fuel consumption, emissions and noise and increase fuel efficiency. Two projects within this research thrust have a direct bearing on NASCAR.

Believe it or not, one of NASA’s big problems is the same problem NASCAR teams battle: drag. Drag is an issue for commercial, military and general aviation. Skin friction — air molecules slowing down the plane by hitting it — accounts for up to 50% of the drag on a transport aircraft, so if you can lower that drag, you can save fuel.

It turns out the two top technologies coming out of that program might just solve the trash on the grille problem for NASCAR.

The Bug Splat Solution

I’m dealing with this project first just because it’s more fun. It’s called the Insect Accretion Mitigation (IAM) program. Boy, does NASA love TLAs (Three Letter Acronyms), huh?

This is one of those projects ignorant people like to ridicule: My federal tax dollars are paying to keep bugs off windshields? Well, yeah. Because bug splats can reduce fuel efficiency by up to 30% when you’re talking commercial-scale aircraft or even over-the-road trucks. Designers go to huge expensive and effort to carefully plan aerodynamics so that air flows smoothly over the vehicle’s surfaces, then bugs deposit themselves on the vehicle and mess everything up, causing the air to become turbulent.

NASA don’t put up with no dirty air.

Not too long ago, we talked about technology that could someday make track surfaces water repelling (superhydrophobic). These materials, which use nanostructure that replicates the surface of lotus leaves, simply don’t allow water to settle on the surface. It turns out, however, that bugs can stick to even the most superhydrophobic surface.

That seems counterintuitive (the scientific term for “WTF?”) because living creatures — even bugs — are mostly water.

When a bug (or a human) is injured, biochemical healing processes are automatically initiated. For example, we produce clotting agents near a wound so the blood thickens and prevents us from bleeding to death. Bugs do pretty much the same thing. It’s those biochemical healing processes that generate the sticky goo you have to scrub off your windshield. The bug’s last revenge on you is that if they’re die, you’re not going to be able to just wipe it away the evidence.

So NASA is developing superhydrophobic surfaces (to repel the watery parts of the bug) and then adding chemical coatings specially formulated to resist the bug’s sticky parts.

Sort of like Teflon for bug guts.

NASA’s “Bug Team”

Yes, they call themselves the “Bug Team”, noting that having fun doesn’t diminish the importance of their efforts to save NASA and commercial transport billions of dollars.

We’ve talked before about how one of the biggest challenges to doing experiments is designing the experiment and building the equipment you need. When you’re doing cutting-edge research, it’s not like you can just order things from a catalog. When you’re trying to do things that have never been done before, you have to design and build your own equipment.

The Bug team is headquartered at NASA Langley in Hampton Virginia, which is the central point for a lot of aerodynamics research for aviation and the space program. There are about 40 wind tunnels available, although some of the older ones are now being torn down and replaced.

A lot of the technology for wind tunnels now used for automotive testing was pioneered at Langley. The wind tunnel used by the Bug Team is called BART (Basic Aerodynamic Research Tunnel) and is shown below. The researcher getting a surface ready to be impinged upon by bugs gives you an idea of the scale.

bspeed_2016_10_tearoffs_bugwindtunnel

The IID: Insect Insertion Device

The next challenge was getting the insects to hit the surfaces they wanted to study. Insects tend not to follow oral directions very well.

So they designed a “bug gun”. In NASA parlance, it is called an IID (Insect Insertion Device)

The bug gun shoots the bugs up into the wind tunnel. (Or as NASA would say, the IIS insert the subject insects into BART.) The wind catches the insects and slams them against the test surface – whether they like it or not. The gun’s repeat rate is just shy of one insect per second at a speed of about 150 mph. In case you want to build you own, here’s the schematic:

bspeed_2016_10_tearoffs_buggunschematic

 

I searched and searched for video and didn’t find any, but they use a super high-speed camera with 50,000 frames per second to record the bug splats so they can study whether different types of splats result in a higher probability of sticking or not.

Your television plays back the race at either 25 frames per second or 29.97 frames per second (PAL vs. NTSC) because that’s fast enough for your eyes and brain to fill in the details between the frames. The high-speed camera they use is taking one picture every 20 microseconds. (A microsecond is a millionth of a second.) If you want to know more about high-speed cameras, check out the Slow Mo Guys on YouTube. I’ll warn you, though, if you’re easily grossed out, be careful what you click on. You may not really want to see slow-motion vomit or a bug being zapped.

The NASA folks started out using crickets, but it turned out that the crickets were too big for the tiny wind tunnel they had, so they changed to using fruit flies because they are the right size and, as anyone who has ever been plagued with them in their kitchen knows, fruit flies breed without needing any encouragement whatsoever.

They tested over 200 different types of surface modifications and came up with the top candidates they thought were most likely to work. They slammed the insects into the surfaces, then measured how much stuff stuck to the surface using optical techniques.  They looked at both how high the residues were (residue being a polite name for what’s left of the bug) and how much of the surface had bug parts on it.

But just as there’s only so much a race team can do with computational fluid dynamics and scale model tests, the NASA scientists needed to do a real-world-scale experiment. So they got a Boeing 757 and mounted the six best surfaces and actually flew the plane around to see what happened. And here they are studying the results. Anyone who thinks scientists are always stuck in a lab is totally wrong.

bspeed_2016_10_tearoffs_nasa_bugteam

 

They’ve got some candidate materials that seem to be extra-resistant to bug guts. It’s a short leap from the chemistry to repel bug guts to the chemistry required to repel other things like rubber and oil. Similar coatings are already being used for windows to keep them cleaner and needing less washing.

So someday, we’ll have NASCAR windshields that automatically repel anything the track throws up at them and we won’t need tear-offs anymore. That eliminates the problem of tear-offs getting stuck on the cars.

Look also for these coatings to be used on car bodies to make then more aerodynamically sound.

That Only Covers One Problem, Though

Yes. We still have the food wrapper/plastic bag problem and it’s not going to solved by the bug-splat research. But luckily, the other promising technology to reduce drag could provide a solution to wrappers or anything else that does get stuck on the grille.

Okay, I’m stretching a little on this one, but bear with me. The AFC (Automatic Flow Control) system re-routes air from the auxiliary power unit to provide sideforce to the tail section, which allows a smaller tail section and decreases drag.

A similar system could be used on race cars to re route air and use it to blow debris off the grille. Blowing outward might not work, but blowing sideways might provide just the right amount of force to get the bag off the grille. The driver would have a button on the dash that would allow them to temporarily close the grille and blow off debris.

Would it be worth it? A closed unit provided by NASCAR might minimize any attempts to re-route the air in non-legal ways. It’s a device that might not be used very often, but if you need it, it would be invaluable. For Brad Keselowski, it might have made the difference between being in the next stage of the Chase and watching it from the sidelines.

Chance plays a role in chases, but something like having an engine blow because of trash on the track seems too much of a chance to play into the something as important as the race for a championship.

More

Leave a Reply

%d bloggers like this: