Breaking the Land Speed Record (Part 1)

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Breaking the Land Speed Record (Part 1)

Post by Guest » Wed Apr 07, 2004 10:57 pm

The Challenge

As you may have read, I have been busy at work with Philoctetes in designing and driving a car that can break the land speed record of 763.035 mph set by Richard Noble's Thrust SSC in October 1997. (You can learn about the history of the land speed record <A HREF="http://www.landspeed.com/learn.html">here.</A>)

Now, you may think it is as simple as going to the old Hockenheim, putting on superglue tyres, an extra pair of underpants and ratchetting up the horsepower until the car can suck the leaves off the trees. To be fair, we felt bound by the laws of physics and so our unspoken rule was not to meddle with the physics of the simulator. Of course, we were free to improve the car as much as the laws of physics defined by the sim's universe would let us, and off we went in search of the number X, that being the fastest attainable velocity as yet unknown.


<IMG SRC="/2004/articles/lsr/indy.gif">
400 kph is possible at Indy after you remove the wings


And it was a venture into the unknown. For all we knew, the tyres would evaporate at 300 mph and become the latest recreational drug, or at the other end of the failure spectrum, we might hit a pebble, launch skyward and become Earth's newest (and frankly least expensive) orbital satellite. Indeed, in one early crash test at the old Nurburgring, the car came off a barrier, shot into the clouds and was still spinning up where the air is clear by the time I got back from lunch. From that day forward, the Esc key became known as "the ejector seat".

The Raw Materials

As discovered earlier, the highest speed attainable with a stock, unmodified Ferrari F2002 car was 382.7 kph (237.8 mph) at the Indy Oval and a lap time around 39 seconds. The Williams had a bit more juice, and by removing front and rear wings it reached 399.9 kph (248.5 mph). Removing the wings reduced drag, while the body of the car still generated enough downforce at such high velocity to enable it to be easily controlled. Since it was apparent that any LSR attempt would require a new design of engine, I thought it more prudent to begin our quest with the better handling Ferrari F2002.

Diary of a Record-Breaker

25th July 2003. Philo sent me our first engine modification package, which had 300Nm of torque over the stock engine and 1100 extra rpm at the top end. Peak horsepower was just about doubled from 740.0 to 1350.9, and sure enough, the car went faster. The trick of removing the wings worked just as at stock speeds, and brought us an extra 8 kph. Since the car was handling perfectly without wings, it was decided to dispense with them from this point forward.
New speed: 453.0 kph (281.5 mph).

26th July. Philo sent over an even better engine, and peak HP was up to 1758.1. While acceleration was rather more stunning, all this did was reveal limitations in the current car design. Even with the tallest gearing available, 7th gear was hitting off the rev stop. The minimum cornering speed was increased enough to knock a couple of seconds off our lap time, but this was not really the point of the exercise. Something else also became apparent: full traction control was not providing sufficient retardation at low speeds any more. Use too much throttle before the downforce kicks in, and the car becomes a very expensive spinning top. I was hoping our exercise would become a challenge for the driver, and today did not disappoint.
New speed: 454.0 kph (282.1 mph).

14th August. We are ready to test a new "LSR" gearbox with a taller final drive bevel. What a dream it is! The engine is able to breathe again, and takes us all the way up to terminal velocity. The car still handles like a dream, but cornering above 300 mph puts so much heat into the tyres that they have almost no grip after a few minutes. The same day, a new engine arrives and registers 1961.8 HP on our test equipment. We switched to a non-wearing tyre compound, but wear is not the problem as much as exessive temperatures that reach 174.9 degrees F. Finally, Philo releases a new diffuser prototype that yields 40% more downforce with no additional drag, and now the car is very stuck to the concrete. A lap of the Indy Oval now clocks in at 27.815 seconds before the tyre display glows yellow and cornering turns into barrier scraping.
New speed: 561.3 kph (348.8 mph).


<IMG SRC="/2004/articles/lsr/lap_times.gif">
The telemetry records a time - and a car - not seen before at Indy


21st August. We arrive at a more promising venue on our hunt for more velocity. The famous Mulsanne Straight of Le Mans is 4 miles long, lined with friendly barriers and in a part of France that the gendarme don't visit. We had local farmers remove the road blocks that funnel cars through the two new chicanes removed, as chicanes and land speed records tend to disagree. The track surface is more bumpy, but all in all, it was better to live with bumps in a straight line than the marble-smooth banking of Indy. The revamped engine now weighed in at 2572.7 HP. Maximum revs were reached in top gear again, and so we increased the final drive ratio. A new problem arose: the clutch was slipping at speeds above 500 kph, necessitating a brand new clutch double the strength of stock. Finally, we stiffened and lowered the suspension since we no longer needed to turn on the Indy banking, and the car could be optimised more fully for straight line speed.
New speed: 628.0 kph (390.2 mph).


<IMG SRC="/2004/articles/lsr/lemans.gif">
Now you see it...Approaching full speed on the Mulsanne


Two more engine modifications result in a peak output of 3794.4 HP. The clutch is bolstered by a further 50%, but now there is so much downforce that the car experiences retardation from bottoming out, despite maximum spring and damper settings. It is now difficult to keep the car pointed in a straight line despite only 10 degrees of allowable steering movement.
New speed: 713.0 kph (443.0 mph).


<IMG SRC="/2004/articles/lsr/lemans2.gif">
Now you don't...At these speeds, the car is not visible for long


16th August. Spring resistance has been increased by a factor of 3. The wings have been rendered aerodynamically neutral and no longer need to be removed. At such high speeds, braking distances are inordinately long. Failed attempts to find a smoother and longer straight took place at Surfer's Paradise and the old Nurburgring respectively. Surfer's simply proved too small, while abrupt elevation changes at The Ring simply tossed the car into the air. Thus we returned to Le Mans, while reducing the car's mass from 602.1 kg to 550.0 kg did not yield the expected reduction of ride height.
New speed: 724.0 kph (449.9 mph).

Engine output was then increased throughout the day to 6034.4 HP. Bumps in the track severely retard the car's acceleration such that maximum speed is reached only on the smoothest sections. The bottom of the car scrapes along the ground above 800 kph due to the high levels of downforce. The strength of the packers was doubled in a bid to raise the car off the track at full speed, but this was not sufficient and yielded minimal results. (Further increases in packer resistance caused the software to malfuction.) The engine was approaching maximum revs in 7th gear so the final drive ratio was increased again, but terminal velocity could not be reached due to the car becoming airborne over bumps.
New speed: 840.0 kph (522.0 mph).

18th August. The engine now puts out 7256.2 HP, and 3563.4Nm of torque. The clutch was slipping and was bolstered again. Some engine power is now leaking through the clutch at rest and causing the car to accelerate unless the driver keeps the brake pedal depressed. Further increases in horsepower were found to be unusable because they cause this power leakage to drive the car forwards even against maximum brake force. It is now a sizable challenge to negotiate the car from the pits through Sector 1 to the Mulsanne Straight without lapsing into an oversteer spin.
New speed: 864.0 kph (536.9 mph).


<IMG SRC="/2004/articles/lsr/864_kph.gif">
Don't try this at home

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