Ed Dempsey
White Lightning is the current land speed record holder for electric vehicles with a speed of over 250 mph, but others are nipping at its battery-powered heels.

The Man Behind White Lightning

An Interview with Ed Dempsey

By EV World

14 November 1999 -- By his own admission, Ed Dempsey could have bought a mega-yacht or a jet airplane with the money he'd made from his demolition and later manufacturing business. Instead, he decided to form Dempsey World Record Associates and go after, among other things, the World speed record for electric vehicles. This past October, White Lightning, driven by Pat Rummerfield succeeded in capturing both the U.S. National and World land speed records for EVs.

At the urging of Rummerfield, EV World set up an interview with the man behind DWRA and discovered a man who wants to do some good with his wealth.

From Demolition Surgeon To Racing Impresario

Dempsey when into the demolition business after college. At the time, the industry relied on brute force of wrecking balls to take apart structures, though a new methodology, one that relied on diamond cutting tools was beginning to emerge.

"We got into the cutting of concrete with diamond tools," Dempsey explained. "That was kind of the new trend in demo work, where you were more like a surgeon instead of smashing the wing of an office building with a crane and a big steel ball, you actually sliced it off like a scalpel."

"As time went on, we found a rather large deficiency in available equipment, so I started developing electric powered concrete cutting equipment, and from that we gained a lot of experience building high performance electric equipment. We specialized in an aerospace power system common referred to as '400 Hertz' and we were able to build motors that produced like two to three to four horsepower per pound. It gave us the ability to go inside of a building and carry a very powerful but light-weight piece of equipment, bolt it on the wall and saw a hole in the wall or floor. Essentially I spent thirty years of my working career doing that."

This became the basis for both Dempsey's interest in electric cars and the technical expertise for building the White Lightning.

His Theories Prove Correct

Dempsey says he's always had an interest in electric cars, but felt that they DC-based technology being used at the time would never produce a consumer-acceptable vehicle.

"I always thought that electric cars were a coming thing," he stated. His experience with 400 Hertz technology led him to believe that AC-based electric power systems might just succeed where DC-power had failed. GM's EV1 proved his theory, he says.

"It's a very similar system to what we use," he said.

According to Dempsey, both the EV1 and his technology take DC-power from the batteries, convert it to AC with a power inverter and use the inverter to control the speed of the electric motor. While this seems, on the surface to be a inefficient way to power an electric car, Dempsey carefully explained for EV World, the reason why AC is more efficient than DC.

"If you take a DC motor very similar to the starter motor on your car," he said, "you put electric power into it and at low speed or no speed, at zero RPM, when you energize that motor you have a lot of torque. As the motor ramps up in speed, a phenomenon called 'back EMF' happens. Essentially what it is is it makes the motor look like a resistor. Where you could draw a 1000 Amps of current from your battery when you first turned the key on, as the thing gets up to half speed or so, you can only draw 500 Amps. To overcome this, you have to keep increasing the voltage."

The back EMF represents the equivalent to the "sound barrier" for DC-based electric drive systems. To get more speed out of the motor requires ever-higher voltages.

"AC power, on the other hand, acts differently," Dempsey continued. Motor speed is regulated by the frequency of the the inverter. The higher the frequency, the faster the motor will turn. "You raise the frequency of your inverter and the motor tries to follow the frequency up," he stated. "The back EMF problem... goes away. What you do, instead is change the frequency, and as the frequency goes up, the motor speed goes up, so your torque is constant. It's a much more drivable, practical system."

A Type "A" Personality

Dempsey says he has a type "A" personality and simply couldn't be content after retiring with sitting around the house. He had built up a small development team and fabrication shop and decided to tackle the challenge of building an AC-powered streamliner. His competition for the land speed record at the time was Rannberg and Healey teams, both of which were using DC-based systems to power their streamliners.

Rather than try to build all the components for the White Lightning in-house, Dempsey and his team looked to outside vendors including AC Propulsion which supplied a pair of 200 hp drive motors and inverters for the car. Each motor/inverter set cost $37,500 and are tied together through a cog belt, giving the car a maximum of 400 hp.

Design and construction of the chassis and body was a joint development effort between DWRA's Bob Kubinski and the Ervid Brothers, a California firm which specializes in race vehicle construction. Dempsey stated that about a half-dozen people, including himself sat down and came up with the design parameters for the car including its length, shape, even the type of tires they would use.

"It's quite an involved effort to get it all down on paper so everyone knows what the game plan is."

Not In It For The Money

When asked about the cost of his electric vehicle land speed campaign, Dempsey pointed out that this is a demonstration program to show that AC-based drive systems are inherently more efficient than DC systems, especially for racing, but also for everyday driving situations.

"What I decided was I had made pretty good money while I was in the concrete cutting business and the machinery building business; and I've got enough money to enjoy the rest of my life with. So instead of buying a jet airplane or mega yacht, or something like that, I decided to invest it in a little racing effort to make the public awareness of this AC power system a little more universal.

"There is no financial gain," Dempsey stated when asked what he personally gets out of his investment. "There is nothing we do that can be applied directly to a production car because, everything we do is at the minimum weight, at the highest performance level. We're kind of like the electronics guy who tunes everything for maximum smoke and backs it off one percent. There is no financial motive in my doing this. It's just, essentially, I'd like to finish my life with making the world just a little bit better before I leave."

Reinventing The Wheel Not Allowed Here

Dempsey said he is a firm believer in not reinventing the wheel when it comes to developing technology, be it concrete cutting equipment or electric race cars. He said he has made it a practice in his business to hire qualified consultants and sub-contractors to help design and build his equipment. He took the same approach when it came to White Lightning. "I guess I pride myself on being able to find the proper people to build a car, to do the instrumentation, to make a propulsion system."

He did admit that occasionally, he can't find the prerequisite outside skills and has to turn to his own small team. This happened in the case of White Lightning's battery system. "We designed the back... the connectors, the connectors to the bus bars. We assembled them in our shop and tested them there. It was something that wasn't convenient. There weren't any people building similar things, so it was kind of a new design we put together ourselves."

Racing For The Record

Dempsey recounted the team's most recent foray to the world-famous Bonneville Salt Flats in Utah. The weather was nearly perfect, he recalled. While the track had its problems, including ruts and a rising water table that made some parts of the track slushy, according to Pat Rummerfield, Dempsey said it was in a better condition than in most years he's been there.

The team caravan consists of a truck and race trailer for the EV and a motor home that serves as team headquarters and rest area. Dempsey said that track rules require each pit area be covered by a ground tarp to prevent contamination of the salt by chemicals and fuel.

Knowing they were going for the World record, DWRA brought along two complete battery packs made up to MolTech (formerly Energizer) nickel metal hydride batteries. In previous race runs, the car had used NiCad batteries. This marked the first time NiMH batteries would be used in the White Lightning and possibly any EV streamliner.

The advantage of the NiMH batteries, Dempsey pointed out, is while they do "sag" a bit more at the start than NiCads, they have twice the energy density of nickel cadmium. This would prove a critical factor in capturing the World record.

"Where the NiCads were running out power at the end of our run before, now we can continue to pull which makes it possible to keep accelerating the car to the end of the timing lights on the long course."

"In the past, we'd run on the short course which is a two mile run up and a mile timed. Here we had a two mile run-up and three miles timed."

Dempsey said that representative of Moltech were present during the record runs and assured him that by next year, they would have a new generation of NiMH with even higher energy density and less voltage sag. "We're quite interested in getting our hands on those new batteries," Dempsey added. Moltech builds its batteries mainly for the portable power tool industry including companies like Black&Decker, Makita and Dewalt. The White Lightning used 6,040 of the NiMH batteries compared to 6,120 NiCads.

DWRA recharges five packs at a time using a new charger developed by Aerovironment. Dempsey remarked that it was quite expensive, but allowed them to recharge more quickly without causing the batteries to overheat. The charger monitors the temperature of each battery pack via a "smart card" attached to each unit. "We watch each packs voltage and temperature as we're charging them," he stated. "It's pretty critical to balance all these packs so that when you put twenty packs online in parallel, one is not charged more than the other, so that one pack doesn't dump power into the other pack.

Capturing US National Record

The previous US and World land speed records were held by Team Rannberg at just over 215 mph. With its new NiMH battery packs and 400 hp dual AC-power drive, the DWRA squad handily beat that mark by a considerable margin of nearly 40 mph.

"We made a one way run just as a demonstration run," Dempsey remarked. "We warmed the batteries up a little more. Generally, we set the battery temperature limit for runs at 30 degrees C for start temperature and we warmed them up to 45 degrees C on the last run and we were able to make that one run at 254 mph."

Ultimately the DWRA car would post a new world record of just over 245 mph and a FIA US National speed record of 251 mph.

Dempsey was on hand for both events and said he, "I felt great" when White Lightning's runs were officially recognized. "It was the finale for a three year effort that started with the concept version and the first run of the car at Bonneville [19]97. As we learned more and more things, one of the things we wanted to do was put instrumentation on the car, so we put a very elaborate recording system on that we had just a nightmare trying to kill off the inverter noise and stuff. It took an enormous amount of time to get everything worked out, so it worked the way we wanted it to. Gee, I feel like we're twice as smart as we were when we started.

Looking Fives Into An EV Future

When asked where he sees EV technology going, Dempsey said he thinks hybrid electric cars will take center stage over the next five years. "This way you don't have the problem with having to stop and charge," he said. "I guess if I would find fault with General Motors effort, they tried to do the electric car... project in one giant step rather than taking baby steps. I think they would have been a lot more successful and helped electric cars, the sale of electric cars and the public's perception of electric cars if they had slowed up and went to a hybrid first and then went to total electric power sometime in the future when battery development was more mature.

He illustrated what he meant by saying that he has a couple of friends who lease GM EV1s. He said that it isn't a car you can drive and not be continually concerned about where you are and the state of charge of the lead/acid battery packs.

In order for EVs to become acceptable to most drivers, Dempsey believes they need to be able to carry four passengers instead of two. "I think first that a two seater is not going to get the job done. I think people want the convenience of having the ability to carry four people in a car." He doesn't see cars like the Honda Insight or the EV1 as being universal enough.

On the topic of batteries, he is convinced they must be recharged rapidly in a matter of minutes instead of hours. "It's got to be convenient," he stated. "You have to be able to get in the thing and go where you're going and come back without ever thinking about, 'Oops I got to have a hundred foot cord here. Let's see, I wonder if the 220 is going to be available here...'"

Dempsey is sure it will happen. He sees the new, advanced batteries as offering the promise of virtually carefree EVs. He even sees them as playing an important role in the development of fuel cell vehicles. High performance batteries will enable fuel cell cars to immediately get underway until the onboard reformer warms up and begins producing hydrogen.

What's Next For DWRA

Besides installing Moltech's more powerful NiMH batteries in White Lightning for another run at the record next year, Dempsey is planning to build an electric dragster. He has also partnered with Don Vesco on a turbine-powered, four-wheel, land speed racer.

As if breaking land speed records weren't enough for this self-admitted "Type A" personality, Dempsey says he's also involved in a project that hopes to send the first private rocket to the edge of space.

He and another visionary, Paul MacCready, are funding a human-powered vehicle competition. He says he greatly admires MacCready, the man behind an impressive list of technological, as well as human-endurance breakthroughs that include the first human powered aircraft to cross the English Channel. MacCready's latest endeavor includes a giant, eight-engined, solar-powered, unmanned aircraft that can fly to 80,000 and could someday replace expensive space-based satellites as communications relay stations.

"It's amazing stuff. I really get behind these new, high-tech ideas. You know, it'll make the world a little better for all of us," he said.

Times Article Viewed: 8372
Published: 01-Jan-2000


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