Bill Hoddinott: Tom, would you walk us through the way you and your team get the car ready for the day at Bonneville and make a pass down the course.
Tom Burkland: Sure, Bill. If it's an SCTA/USFRA meet like Speed Week, World of Speed or World Finals it's one thing. If it's a private time meet like last fall when we were running for the FIA world record, it's something else. Especially at Speed Week, with the large entry, you may find yourself waiting in line to run for a long time.
Anyway, when our crew gathers first thing in the morning for warmup, we take the upper engine cover off, a careful process in itself with four lifters and a director.
We have external plug-in power for cranking, plenty of battery power and wired up to hit the 12 volt starters with 24 volts. Which gives them more torque and cranking speed to fire the magneto ignitions, but the extra heat load doesn't hurt them for a few moments of cranking.
We have fresh clean warmup spark plugs in the engines for morning startup. These are hotter plugs than the race plugs we will install for the run later. The hotter plugs resist fouling from running with no load for warmup and are less likely to bridge with the liquid fuel on their extended gaps and electrodes.
The whole process is controlled by the driver for safety so I climb in the cockpit with the canopy open and the starter switch is passed in to me. I turn the fuel valve on, leave the mag switch off, and at my signal, a crewman pours the measured amount of gasoline prime into each of the two gutters in the air intake so it runs down to the throttle bodies and I hold the throttle open so it drains into the blower, then shut the throttle again.
Next I push the clutch in and hit the starters and crank the engines for a few seconds until I see oil pressure starting to build on the cockpit gauges. At that point I flip the mags on and they SHOULD fire up. We put enough gas prime into them to give time for the fuel injection pumps to purge their lines of air and start delivering fuel to the throttle body nozzles. The air volume of the blower manifolds is considerable so you need plenty of gas to get a burnable vapor for cold morning startup.
The engines normally fire easily. The 60 weight oil gets kind of thick overnight in cold weather but we haven't found any kind of oil heater necessary.
When the engines fire and keep running, we unplug our external power and run them until they reach full coolant temp and the oil warms up. The electric water pumps allow this warmup to happen with no water flow in the engine jackets to save the cool water for the coming run, when it will be needed to maintain engine temperatures. We look everything over, check for leaks, put our race plugs in and replace the engine cover, then we pile blankets over top of the body to try and keep the heat in the engines. Then go take our place in line.
Bill: It could be a long wait, do you find the engines fire up readily after sitting for an hour or two?
Tom: Yes, and we don't have to use a gas prime then as a rule. I just hold the throttle open a little to let extra fuel go in there for a prime, and they start.
Bill: The heat can be tremendous out there at Speed Week, do you use a Kool Vest or similar?
Tom: I use a 3.2-20 Funny Car-style firesuit which I put on just when we're getting to the front of the line and no, I haven't ever felt the need for a Kool Vest.
Bill: What does the driver experience when he gets into the cockpit?
Tom: It's tight by design, tailored to suit me, but I sit fairly upright, my back only inclined at 15 degrees. The tight fit makes you feel comfortable and confident, and I know I can rely on all the Gene Burkland welds in the rollcage! There's a butterfly steering wheel which turns 90 degrees to the locks at each stop to give 5 degrees on the front wheels.
You're looking through a three-inch-square windshield between one row of gauges above, and another one below. You don't check all your gauges during a run, but you keep an eye on the needle positions to keep all of the critical parameters within operating limits. The oil pressure (one for each engine) to make sure the engines are safe, fuel pressure (one for each engine) to make sure the bypass systems are functioning correctly, manifold pressure (one for each engine) which would tell you if a blower belt broke and if the blower performance is consistent with the throttle opening; the tachometer for shift points and wheel speed reference, and the air speed indicator for a more accurate ground speed reference. We find this air speed indicator matches the timing lights within 15 mph or so. There are water temperature gauges for each engine and a set of oil temperature gauges as well for each engine that can be checked if the warning light system illuminates to draw the driver's attention.
After the 2001 crash we incorporated a helmet bumper on the canopy latch which drops down to support the front of the latest spec - Snell SA 2000 - helmet. It serves the same function as a Hans Device and prevents the helmet from snapping forward in a frontal impact. This also holds the helmet upright during the high-deceleration parachute deployments so the driver can still see where the ride is taking him.
My entire upper body is snug in the seat and rollcage padding and my legs just free enough to operate the controls. As noted before in this story, the throttle pedal is low down on the left, operated by my right foot, and the clutch and brake pedals are above it, with my left leg on a shelf to support it and operate them. This is necessary because the front Liberty gearbox is in the right front of the cockpit, and the driveshaft for it runs along my right leg. Both of them have stout shields over them. The one for the driveshaft beefed up even more since we had a u-joint break in '06 and the shaft banged my hip through the previous shield. Enough to bruise me but not break anything and give us all a lesson in how strong drive line components really need to be in this environment.
My arms are secured in the arm restraints as much as possible where I can still operate the essential controls and switches. I'll tell you later what we learned about arm restraints in my 2001 crash.
My helmet doesn't have more than a quarter inch of clearance to the rollcage padding in any direction, to reduce the potential G forces in a crash, but I must have that much clearance to find a position where the severe vibration in the car doesn't blur my vision.
Bill: How long does it take you to get OUT of the car in an emergency, from completely strapped in?
Tom: Only twenty seconds and we've practiced that well, too!
The Starter tells us to fire our car up and we go through our drill, with the canopy open and the driver in control of the process. It fires, the Starter checks the driver's harness, the canopy is lowered and locked by the crew, and the Starter gives the GO signal.
Our truck pushes the car up to 30 mph, which equals 1800 rpm idle speed in first gear. The driver pushes in the clutch and selects first gear, then applies a little throttle, feeds in the clutch and pulls away. You can ONLY give the car about 5% of throttle in first gear otherwise you have massive wheelspin. Which you can't allow because you don't want to overheat and abuse your tires, which only have .090" of tread depth on them.
The car accelerates hard even at 5% throttle and you run it up to 4000 rpm in first gear, then lift momentarily and use the electrically-triggered air shifter button on top of the right steering wheel grip to get second instantly (the clutch is used only for starting in first gear) and you feed in a little more throttle as you go through the gears. You use 4000 as a shift point in first and second, then 5000 in third and fourth gears. The car needs to accelerate to 300 mph in nine to ten seconds, and you need to be into top gear well before the 4 mile marker. During the FIA record I was around 5800 rpm in top gear. These 450 Donovans could easily sustain 7500 without damage so there is plenty of room to run faster if the traction were there to hang onto the power.
Bill: What about the vibration characteristics of the car?
Tom: Up to 100 mph there is a sideways vibration pounding the driver as the wheels go over bumps and washboard on the course and it sort of rocks at a high frequency due to the narrow tread width and the CG height. You have to hold your helmet away from the rollcage padding or it affects your vision.
From 100 to 300 mph the ride seems smoother because the weight of the car makes the tires flex and absorb the bumps better even though they are inflated to 90 psi.
From 300 on up to maximum, it feels like the tires become literally solid from the centrifugal force on them so they no longer can absorb anything. Now you get an extreme high speed vibration throughout the whole car from running over the ground surface and you MUST hold your helmet away from the rollcage a little or it will affect your brain and your vision so that you can't safely operate the car!
Inside the rollcage the driver hears little of the mechanical or exhaust noise of the engines due to the firewall and the exhaust exiting so far behind him. What he hears is high pitched gear whines from the gears in the transfer case and the front Liberty gearbox.
At very high speed you're going way too fast to read the track surface, the mile markers look forty feet high and fly by so quickly you can't read them! I have gotten in the habit of counting the markers from about a half mile away to know where I am on the track and get shut down as close to the end of the timers as possible. This makes it very important to have driven the course and know what the marker configuration is, where they are in relation to the timers, and what the shut down area looks like, especially the over run beyond the prepared track surface.
You modulate your throttle carefully all the time to keep from too much wheelspin, and we have never been able to use all the available power. Since the driven front wheels are slipping to a degree, their steering ability is compromised. In fact, one time just for a test I turned the steering wheel to the lock at 400 mph to see how the car would react. It reacted NOT AT ALL! At that speed your stability all depends on the aerodynamics built into the body. As mentioned earlier, your center of pressure and CG have to work together to enable the body to steer into a slight crosswind, rather than be blown sideways by it. But the bottom line is, near maximum speed I can only place the car on the course within about 40 feet sideways (half the track width). That's just the way these super-fast wheel-driven cars are.
All right, you're entering Mile 5 on the Long Course in top gear, in a WORLD of vibration, and feeling for wheel grip to try to get every mile per hour you can through the lights!
In the last half mile, you put your left hand on the set of controls that shut off the fuel and ignition and open the tail flaps in one motion, trying to synchronize this with clearing the last timing light on the course.
Your chute doors open and form a big air brake which gives you a 3 G smooth deceleration hit. Your #1 chute comes out in its bag almost immediately, goes to the end of its 110' tether, opens and gives you a 4 to 7 G shot, which is like hitting a brick wall at 40 mph. At 350 MPH you manually deploy your #2 chute based on the air speed indicator unwinding and the shut down area flying past. These two pull you down hard. At 250-275 mph you can use your #3 chute, but you don't have to. Using all of them will stop you in two miles, but it's easier on the driver and the whole car to just use three miles to stop. At 150 mph and under you can use your wheel brakes for the final stopping as you pull off the course. A smooth graded long-radius turn out is essential to safely getting this car off the course so if you are far enough down track a straight-out stop on the prepared surface may be the safest.
Now you stop, open the canopy, remove your harness and step out. About this time Chris and Ed Shearer will be arriving with the cool towel, cold drink and the preliminary time slip. They will be followed very closely by our own chase vehicle coming from the seven mile in hot pursuit so the crew can spray down the exterior
surface of the engine bay and cool things down.
Bill: Very good, Tom. But before you developed the parachute system you use now, you had your first edition, which completely failed at 450 mph in 2000 and gave you a wild ride out into the boonies off the north end of the course! Tell us about that in the next part and what you did about parachutes.
Copyright 2009 Bill Hoddinott