Buyers Guide Forums Information Buy/Sell Communities Build/Tech Racing Site
MARS library - Texas Event
What's New



Mailing List







Texas Event

Photos and text by John Tetz

During the week of Nov 15-22, 2003, the Varna team went to Uvalde, Texas (90 miles west of San Antonio), and tried to win the $25,000 Dempsey MacCready Prize for doing 55.923 mph for one hour on one of the Continental Tire test tracks. Continental has several tracks to test car and truck tires under various conditions. They graciously let us use the 8.5-mile track for free (most tracks cost $1000 to $1500 a day).

This shows Georgi Georgiev ( and Paul Buttemer fitting the top (silver) to the tub section (black). Behind is Paul Gracey, one of the official observers. I was the second official observer.

Note there are no foot openings, so a tricycle launch gadget is needed to support the vehicle (tail end) during the beginning of the launch. When the speed of the bike is stable enough and the rider has command, the launch gadget is pulled off. Two runners are required alongside this crucial start run just in case the rider loses control.

This shows how tight the insides are to reduce frontal area. Note how Sam Whittingham’s shoulders are forced inwards. His shoulders were toast at the end of the hour run (this vehicle was designed for sprints). The numbers marked on the inside of the windshield are lap times that he needed to be at for each lap. Sam also has a SRM display reading his power in watts just below the windshield. No, he cannot move his head, only his eyes.

A top view of the nose, showing how narrow the front end is.

Note how small the front wheel opening is. Not much turning capability. This is one reason the launch gadget is needed. That, and the gearing is very high.

This was taken in the middle of the week while preparing for the actual record attempt. Previous days were needed to scout out the best track conditions (two of the three lanes were quite rough, for Continental tire testing), make various test runs, for Sam to learn every detail of the track, and for us officials to make detailed distance surveys using a GPS system borrowed from the track. And we had to wait for good weather – we had only this day of no wind and 80 degree temps. I was the chase car driver, so between the many tests and surveys and following Sam around the course, I probably put on about 200 miles on the chase car. I almost ran over a 6-foot rattler.

Here Georgi and Paul Buttemer are lowering the top. Then they tape the top to the tub section. This means the rider has to be caught at the end of the ride.

Here Paul is catching Sam. Kind of tricky because Sam has to make sure he has enough speed to prevent wobbling and falling over (lack of wheel opening), yet he doesn’t want to come in too fast and overrun the catcher. Ouch.

Here is the end of the record attempt. Sam put everything he had into this event. He had trouble getting enough energy out of his legs to stand up.

Being the chase driver and watching this event unfold was extremely intense. At the start line I was one of the start runners, and once Sam had control, Georgi and I ran back to the car. Paul Gracey was already in the car and had started the hour stopwatches and the GPS receiver system. We took off and had to get up around 80 mph to catch Sam in that short time (slight downgrade start). The rules state a chase vehicle needs to be following to make sure the rider stays outside the surveyed line, and to be no closer than 30 meters.

This track has a few long grades (they looked like 2%) about a mile in length, and Sam had predetermined to average 275 watts for the hour (which he did quite well), so his upgrade speeds dropped averaging in the mid 40s range (think about trying to do these speeds up a grade!). Seeing these long grades and all the effort needed to keep that kind of speed felt excruciating to me, even though I was only pressing ounces of effort on the gas pedal.

Sam recently sent me his SRM data, and out of those plots I calculated that the grades are around 1.5%. Here is the method:

I was able to scale off the plots the change in speed over time, which gave me the decrease in acceleration per second. Then I plugged this negative acceleration into the Power Spreadsheet (PDGus1.xls, Sanders/Snyder/Tetz, download from the Tools page of the IHPVA website), and voila, the power came very close to what Sam was indeed putting out.

Here are the details: On lap 4 at 2 min 51 sec into the lap, the speed was 52 mph (sorry, I think better in mph). At 3 min 17 sec, the speed dropped to 46 mph. The shape of the speed plot was quite linear through here (that's why I picked it). So in 26 sec, the speed dropped 6 mph, or -0.23 mph/sec. Plugging the -0.26 mph/sec into the PDg spreadsheet and setting a speed of 48 mph (middle of the grade speed), I then adjusted the grade to duplicate Sam's power, which was around 289 watts during this section, resulting in a grade of 1.55%.

Back to the record run.
About halfway through we knew we wouldn’t be making the 55.923 mph needed for the Dempsey MacCready Prize, so we waited to see if Sam could break the hour record. It was a close call. At the end of the hour Paul Gracey did a countdown while I came a bit closer to Sam so I could pick out a reference point where Sam would be at the end of the hour, then hit the brakes hard to stop on that spot and mark it with a sock with powder in it (later made a GPS distance measurement). Then take off to catch up to Sam again because we had arranged that if he was toasted and wanted to stop, he would change lanes and slow down, which he did.

Sam did break the hour record (held by Germany) by 1121 meters, which translates to 52.2 mph. Verification of all our measurements will be required.

These are the people needed for a record event. From right to left: Ella Sararron, a Continental official (without all her help none of this would have happened), Paul Buttemer (one of the original Varna riders, team organizer and data organizer), Sam Whittingham (fastest man in an HPV - in the Guinness Book of Records we saw in a store in Antonio), Paul Gracey (who has done all of the timing at Battle Mountain and other record events), Georgi Georgiev (a Bulgarian sculptor who has created the fasted Human Powered Vehicle in the world), and a lucky MARS member.

Note how slick that bike looks.

John Tetz
Succasunna, NJ
November 2003

Click here for Sam Whittingham's 12/3/03 report, "My 60 minutes of hell", to the Streamliner newsgroup.