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RACER.com Diary 12: Ones and Zeros

Throughout the update, we’ve taken pains to ensure that the Challenger II stays old school. But we’re traditionalists, not Luddites. Electronic systems are a major component of contemporary racing, and our team has embraced that. Leading this effort is Donny Cummins of RacePac, a really smart guy with a proven product. He’s been collaborating with A/Fuel Dragster guru Jerry Darrian to come up with our engine monitoring system. 

As those of you who’ve been following us for a while know, the Challenger II is a four-wheel drive vehicle with dual engines. The power plants interface with each other via Hadley Boxes, which are basically bespoke gearboxes that mechanically balance output. Given that the two engines are being built of identical parts by the same group of people, they should be perfect doppelgängers. But they’re not, and that’s where the electronics come into play. Donny’s products allow us to measure twenty different variables simultaneously and identify even minute inconsistencies. That data helps us maintain uniformity during the run, and reduces the load on the Hadley Boxes, which rely on difficult to repair metal gears rather than easily rebootable ones and zeros. 

We also have the ability to monitor the status of the chassis. This is absolutely essential, as its characteristics will change markedly over the course of the run. For instance, at the starting line, the nose of the car will contain nearly sixty gallons of nitro blend. By the five mile mark, most of that volume will be gone, reducing the vehicle’s curb weight by over five hundred pounds. If everything is going well, we’ll be going over 400 mph at that point, every yard of which will cost us front traction in the form of reduced weight. If we don’t properly compensate for that with aerodynamic down force, we’ll be in a world of trouble. The electronic monitoring, in combination with extensive testing, will allow us to fine tune the adjustments necessary to predict changes in the car’s attitude and lift over the course of the run. 

In short, although Donny may not have been around in 1968, we’re very glad that he’s here now. As the struggle for sponsorship continues, we’ve been exploring a different approach that we’ll discuss in the next article. See you then!

RACER.com Diary 11: Old School Aluminum

The design and engineering of the original Challenger II was a close collaboration between my dad’s crew of hand-picked drag racing guys and Ford’s in house Kar Kraft team. The point man at Kar Kraft was Ed Hull, who you might recognize from some of Ford’s more spectacular projects, including the GT40 Mark IV. The two groups had gigawatts of brainpower, but they also had a lot of practical experience, which lead directly to some of the Challenger II’s more superficially confusing features, including the segmented aluminum skin. 

The credit for that goes to Nye Frank (a hero of mine), who had worked on Craig Breedlove’s Spirit of America, and was constantly frustrated by the need to remove large portions of body work in order to perform simple maintenance or repairs. The subdivided architecture of the Challenger II means that almost all areas can be accessed quickly and independently by popping a few Dzus buttons, an advantage that we’re counting on to make the FIA’s mandated one hour turnaround. To see it in action, have a look at the video underneath this article. 

I’m often asked if the sheet metal work is original, and the answer is an emphatic yes. The body was crafted by Tom Jobe and Nye Frank over forty-five years ago, and is an absolute work of art. The only changes so far have been the relocation of an air intake and a 32 inch extension to the tail section on the recommendation of our aerodynamicist Tim Gibson. Matching the existing work meant finding old school talent, and we were fortunate to locate Terry Hegman, who is one of the world’s last truly gifted aluminum men. As a fellow fabricator, seeing his work each week leaves me green with envy. 

When you look at the flowing lines of the streamliner, it’s impossible not to see it as a thing of beauty. From above, it looks like it’s breaking records standing still. If I were building a new car from scratch, there’s no question that I’d be using carbon fiber instead of aluminum, but I really don’t think I’d get the same overwhelming sense of craftsmanship. When I look at the Challenger II, I’m reminded a little bit of Apollo 11, which launched about a year after the streamliner’s rained out test run. It’s got a real sense of adventure about it, and I like it that way. 

 

RACER.com Diary 10: Making the Turn

A great deal of effort has gone into making sure that the Challenger II travels in a straight line. If you happen to see it changing direction quickly, cover your eyes, because what happens next isn’t going to be pretty. Although the car’s aerodynamic properties should do most of the work of keeping it level, an inordinate amount of attention has also gone into the steering. We’ve reserved enough packaging space to provide the streamliner with up to five degrees of back and forth maneuverability, but that number will probably be artificially restricted to a lower amount after our initial test runs. At Bonneville, slow movement is safe movement, and we’ve engineered the car to respect that.

Of course, some steering is necessary to get the liner off the track at the end of the run.  This is especially relevant during Speed Week and other SCTA/BNI events where many cars participate in quick succession. Fortunately, when you’re traveling at very high speeds, it doesn’t take long to cover the lateral distance to the recovery area.  And for the events mentioned above, that’s really all it takes. If we’re fortunate enough to get a record, we’ll load the vehicle onto the trailer and head to impound. We won’t have to make the return run until the next morning, which gives us a bit of breathing room and ample time to prepare. If we don’t make it, we’ll head back to the pits, perform adjustments, and try again.

Unfortunately, FIA runs aren’t that simple. In order to capture that record, we need to turn the car around and backup our previous run within one hour. In our case, that means adding sixty gallons of specially prepared fuel, changing the oil in both dry sump tanks, switching out 32 spark plugs, adjusting both engines, examining the tires, and quickly but thoroughly performing checks on all the streamliner’s systems. We also have to do something that we’ve intentionally made very difficult, which is turn the car around. With five degrees of steering, making a loop in the Challenger II would require almost a mile of runway. At 5500 pounds, it’s too heavy to easily move, and loading it onto the trailer in order to reverse it requires time that we probably won’t have. 

Luckily, the very smart Bob Skinner came up with an ingenious solution to this problem more than 45 years ago. Nestled inside the body of the Challenger II are four huge air jacks. When it’s time to turn the car around, a simple application of air pressure causes them to deploy downwards, elevating the entire streamliner six inches off of the ground. Next, two crew members will slide a purpose built lazy Susan underneath and rotate the vehicle 180 degrees. Once it’s facing the right direction, we’ll reverse the jacks and gently lower the car back to the salt. In testing, this takes a mere five minutes and allows most of the crew to continue working throughout.

RACER.com Diary 9: Precious Cargo

As we get closer to the streamliner’s first test runs, we’ve had to devote some time to the logistical challenges of transporting such an unusual vehicle. The salt flats are a unique environment that requires a fair amount of esoteric planning, especially when it comes to the best way to move the car around the speedway. The unexpected softness of the salt, especially at the north end where vehicle recovery takes place, has been causing problems for people since at least the 1800‘s, when the Donner Party got stuck indefinitely and ended up eating each other. We’re more likely to encounter a string of tow trucks than a gaggle of cannibals, but we’re professionals, so we decided to take the problem seriously anyway. 

The Challenger II has grown a little bit lately, and is now just over 32 feet long. The ground clearance is a meager two inches, so the most immediate problem was getting the car off of the trailer without scraping the bottom or damaging the strake. We also wanted to minimize weight if possible, as the streamliner itself is already relatively heavy at 5500 pounds. That particular concern led us to abandon the idea of an enclosed trailer (which was my preference), and sent us on a hunt for the best already existing uncovered trailer we could find.

That eventually led us to Seth Hammon, who in my opinion has the nicest rig on the salt. Using his trailer as a baseline, the very talented John Pollorena has been building us a modified version specifically for the Challenger II. The first thing he did was narrow it by 10 inches. This will allow us to comfortably work on the car without having to remove it from its transporter, and mimics the height of the frame fixture we use at the shop. Another unusual feature is the axels, which are on arms welded to the side of the main rails instead of under the framework. This allows a system of air bags (similar to what you’d find in a semi) to slowly lower the bed of the trailer flat to the salt. From this position, the ramps can deploy at a 2 degree angle over a span of thirty feet, giving us a comfortable .5 inch clearance impediment for loading. There are a few other modifications as well, including a toolbox mounted at the nose and an integrated 100 gallon water tank over the fifth wheel for washing off excess salt. 

Things are coming along! I hope you’re enjoying the updates. See you next week.

RACER.com Diary 8: Quenching the Thirst

I mentioned a few entries ago that the updated Challenger II is using dry block engines that don’t require radiators or a water system. All the necessary cooling is provided by the large amount of fuel being fed to the engines. We estimate a consumption rate of approximately 20 gallons per minute, which works out to about 0.083 miles per gallon. The Brown & Miller fuel line is constructed out of braided stainless steel and has an unusually large diameter at 1.25 inches. It snakes through the streamliner’s superstructure in order to feed both engines. 

Our fuel system utilizes four injectors per cylinder. One of the four is only used to start and warm the engines. A simple two gallon gravity tank sits on top of the body work and feeds pure methanol through the system while the beast gets up to temperature. When it’s suitably hot, Frank Hanerhan will radio me to turn on the internal pumps and we’ll switch over to the onboard nitro blend. 

Given the car’s profile, the actual process of fuel injection is a real challenge. I sit in a semi-reclined position and look through a 7 inch curved windscreen. There’s almost 13 feet of body work in front of me, so keeping the manifolds and injectors low is essential. The intake manifold is only 5.875 inches above the top of block, and the throttle body is actually situated in front of it rather than in the apex position. All of this is duplicated in the rear engine for the sake of consistency. If something goes wrong, we don’t want to have to think about how to fix it. 

All of this is being handled by the extremely talented Jerry Darien, who’s somehow managed to design a system that meets our extremely compact packaging requirements. How he’s managed to fit in the barrel valves, metering blocks, return lines, bypass systems and all the other component infrastructure is a little bit mind boggling to me. 

Now, here’s the money question. If the engines are cooled by fuel, what happens to them if I let up on the gas pedal during the run? The simple answer is that they’ll probably blow up. There’s not really much room for compromise with this setup, so if I feel like something is going wrong, there is a good chance that I’ll cut the engines immediately. Finger’s crossed! 

Thanks for following along. See you next week.

RACER.com Diary 7: Engineering Agony

The Challenger II was built in five months. I’ve been working on it full time for almost two years, and it’s the hardest thing I’ve ever done. The problem, I suspect, is that my dad hired a team of geniuses to design it, and another team of geniuses to build it. I’m just a race car driver that likes to weld. The engineering and packaging complexity is so omnipresent that a 1969 magazine article called it “on par with a lunar module.” Most days, that feels about right. 

When we run into problems, they don’t occur, they cascade. I’ve already had a couple of smart guys give-up on the project because of the difficulty. Very high speed racing is such an esoteric undertaking that a lot of the equipment and expertise we need is outside of the automotive community. In the past six months I’ve spent more time researching material properties and manufacturing technology than I have building stuff. But I’ve learned a lot, and I’ve found a few invaluable guys to help me overcome the hurdles.

Tim Gibson is our aero engineer, and he’s been tackling the front steering, which is the most complicated aspect of the liner in terms of packaging. He has a little under 35 inches to work with, which is the width of the car. Sitting directly in the center of that space is a 12.5 inch rear end (not a front end--we have the forward engine facing backwards), which leaves him with 11.25 inches per side. In that space he has to fit a spindle with a split king pin, a brake caliper, a brake rotor, a u-joint, a wheel, and a tire. After he’s done all that, he has to make sure that there is enough space left over for 5 degrees of steering in either direction. 

After Tim figured out how to draw the front end, we had to determine how to build it and where to source the materials. We knew we needed to assemble the u-joint out of a specially heat-treated maraging steel. Unfortunately, the u-joint is made up of two splined yokes that fit together precisely. If we tried to cut the splines after the heat-treatment, the metal would be too hard. If we cut them before, the slight warping caused by the process would ruin the perfect fit. We needed something that could cut extremely hard material to very close tolerances. The answer, it turned out, was something invented in the 1940s called electrical discharge machining. I’d tell you more about it, but according to Wikipedia “it appears that the material removal mechanism in EDM is not yet well understood.” So there. 

What matters to me is that it works, and it brings us one step closer to the salt. Thanks for following along. See you next week.

RACER.com Diary 6: Mystical Bonneville

What’s so great about a dried up lake in the middle of the desert? It inspires a kind of racing that you don’t get to see anywhere else. Rank amateurs labor next to hardened veterans under the boiling sun, moving heaven and earth to wring just a few more miles per hour out of everything from electric bicycles to million dollar streamliners. It’s a mystical place, a throwback to a time that felt messy and pioneering. If you haven’t been, go. It must be experienced to be understood.

Although Bonneville holds an exalted position in my dad’s personal canon, I didn’t spend much time there as an adult. My first visit in decades took place in 2003, when I was invited to drive a restored streamliner called The Pumpkin Seed. Given my professional background, I was a little bit cocky. Get in the car, keep it straight, pull the chutes and grab a beer. That was the plan anyway. It took me about 30 seconds to realize that everything I knew about driving had to change. On the salt, going fast can be painfully slow. Quick hands and instant reactions might send you tumbling. The conditions, which can vary enormously in the particulars, are always slick. Success at Bonneville requires a certain zen, and the fastest moments of your life can feel like they are coated in molasses. 

Another aspect is scarcity. We all want what we can’t have, and the speedway offers a narrow window of accessibility. Typically stretching from August to early October, the three month span becomes the equivalent of childhood’s summer vacations. Precious, eagerly anticipated, and all too easily disrupted by life’s unavoidable obligations, time on the salt is made more meaningful by it’s brevity, and the knowledge that if you miss your shot, you might not get another chance. That was certainly the case with the Challenger II. A burst of rain and an afternoon of wind kept it out of the record books for five decades. Hopefully we’ll have a little bit more luck this time around. 

See you next week.