Beating Plowshares Into Dragsters

May 10, 2007
How do you keep the boy on the farm after he's won the FIA (Federation Internationale de l'Automobile) championship?

Ulf Leanders
Driver for Team Leanders

The IronCad methanol-fueled dragster waits for 6 sec of F-A-S-T.

Jörgen Leanders used IronCAD software to design this durable, lightweight, easy-to-disassemble clutch.

The smell of burning methanol fills the air … thousands of spectators rise from their seats … the raw power of 3,000 horses strains at the bit … the dragster's carbon-fiber body shakes … the orange light switches to green … and in just 6 sec … it's over.

I'm Ulf Leanders, driver for a Swedish drag-racing team, Team Leanders. Drag-racing success has ended my days of farming and my brother Jörgen will probably follow soon. Since 2003, our IronCAD methanol funny car has been a top qualifier. And last year, we garnered 374 points to finish first in the Top Methanol Funny Car class.

Drag racers are always looking for ways to improve their cars' performance. All competition vehicles are built from NHRA or FIA-approved parts, so the equipment is similar. The NHRA and FIA regulate parts to prevent any well-financed team from gaining an unfair advantage. A team needs SFI Foundation approval to use a custom part, and they must make any such part available to the other teams. Prototype parts are shipped to San Diego for rigorous testing. Clutches, for example, are mounted on testing brackets and run at 15,000 rpm for 1 hr. Tensile (stress) tests are also run.

Dragsters fall into classes ranging from 800 to 6,000 hp. The so-called funny cars run eight-cylinder engines with a single camshaft — old technology compared to your family car, with its multiple valves and four camshafts. But old-school design doesn't mean less power: a methanol-burning, 1960s-inspired 428 Hemi puts out over 3,000 hp, firing it down the track at over 250 mph.

A few well-funded American teams design with CAD but most European teams don't. Team Leanders is one of the first European teams to use CAD in a FIA-sanctioned vehicle. Our primary sponsor, IronCAD, provides the design software. Jörgen designs our frames, bodies, and clutches in IronCAD. The introduction of CAD is changing European drag racing. It used to be trial and error. Now, we fine-tune our cars even before they're built.

Last year, General Motors and America's Team Skoal used CAD to design a new body for their Impala SS Funny Car. Mathematical computations complied with NHRA regulations. They improved the aerodynamics, making subtle changes like windshield angle to smooth the car. In 2005, Jörgen used IronCAD to map a new racing body. He used Algor integration to test the design without building a prototype. Unfortunately, we were unable to secure the financial backing to build it.

Funny cars have many parts in common with street racers, but while funny cars use methanol injection, street racers have nitro S-injected gas engines, different compression ratios and piston clearance. As a result, the average output of a street racer is 500 hp versus 3,000 for a funny car.

Funny cars, or any drag racer, must successfully transfer power from the engine to the wheels. The clutch is critical. Because the clutch uses friction to transfer power from the flywheel (on the engine) to the clutch plate (which connects to the transmission), it wears out. Pads on a clutch, similar to brake pads, provide friction to keep the flywheel and clutch plate moving in unison. But when you're dealing with high-horsepower engines, clutches wear out fast. The average lifespan for a dragster's clutch is four times down the track. With only 90 min between races, pit crews want clutches that disassemble easily.

Currently, we use a slipper clutch, a specialized clutch originally developed to mitigate the effects of engine braking on racing motorcycles. In drag racing, slipper clutches partially disengage or "slip" to regulate the amount of power to the wheels. Jörgen, with no previous engineering experience, is using IronCAD to design a custom-built clutch.

He uses integrated FEA programs like Algor to test the clutch's strength. After assembling and disassembling it in 3D, the new clutch should save precious time on the track. Blowing a clutch on the track could be fatal to the driver and onlookers. That's why we make clutches from aluminum and titanium.

Standard racing clutches are made of aluminum, with bolted steel segments that transfer heat. The heat makes the aluminum parts flex and bend. Replacing aluminum with titanium makes the clutch heavy. Jörgen's answer, the Leanders clutch, uses a floating-plate system (as opposed to bolted segments). It's easy to take apart and the air pockets improve heat dissipation. Dave "Grumpy" Wilson, the 2006 FIA European champion for Top Methanol Dragster, and Team Leanders will test the new clutch. IronCAD also sponsors Wilson's team.

We use a design-as-you-go method of CAD modeling. After identifying a problem, we consult the FIA rulebook. Designs evolve from compromises between whatever solutions we come up with and the regulations. Jörgen typically starts with the chassis. Then, he models the dragster around it. Piece by piece, he adds brackets, wires, axle plates, engine mounts, engine, and other parts. He experiments by changing component positions, designing parts as needed.

Jörgen often designs his own parts, but he also uses a library of custom parts (like the sheet-metal catalog) for basic shapes. He stores some of his designs in catalogs, for future reference. IronCad's center-of-gravity calculator helps determine design feasibility.

Team Leanders and IronCad partnered in 2003. The following year, we ran a 5.666-sec quarter mile, the fastest time in Europe, to date.

The new season kicks off this month at Santa Pod Raceway in England. The chassis has been inspected for cracks; we have the SFI certifications we need; and we're stocked up on spare parts. Our methanol-fueled run for another championship starts now.

Driving a funny car is like riding a rocket; it's a feeling you never get used to. You can't be nervous in the cockpit or it will affect your reaction time. I'm confident because my team is composed of professionals. I'm so sure of them, I stake my life on it.


From whiskey in the trunk to methanol in the tank
Drag racing's roots date to the 1920s and Prohibition. Bootleggers, anxious to make their fortunes, hired drivers with fast cars to move the precious cargo. The cars looked like other cars but the engines delivered enough power to outrun the law.

When Prohibition ended, these souped-up cars and their thrill-seeking drivers gave birth to hot rodding. In post-World War II America, hot rodding flourished at dry lakebeds like California's Lake Muroc and the Mojave Desert. Top speeds reached 100 mph.

In 1950, the Southern California Timing Association sponsored Speed Week at the Bonneville Salt Flats. Drivers raced a quarter mile, against a stopwatch. In Europe, drag racing didn't catch on until the '60s when old airstrips were converted to racetracks.

Five decades later, the legacy continues with America's National Hot Rod Assoc. and Europe's FIA.

Drag racing, FIA-style
FIA races usually last three days. Friday is practice; Saturday is for qualifying; and Sunday's eliminations decide the winner. The format is double elimination, pitting the winner of one race against the winner of another. But before they can race, the crews break down and rebuild the engine and clutch. They check out the entire vehicle. At 250 mph, even minute damage can be disastrous.

Prerace tuning ensures the car performs at the edge of the traction threshold. When the car is ready, an on-track burnout warms the tires, increasing their grip. The driver backs the cars into stage (starting) position. When the green light comes on, the cars explode off the line. Drivers wrestle for control, looking for that delicate balance between power and traction. Too much power and the rear wheels spin; too little and the wheels shake. If the stress is too great, the car could be damaged.

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