Jan 26, 2005

The 6, 12 and 24 hour human powered vehicle records

Here are the current records as indicated by the iHPVA web site:

If I was to take a shot at any of these three records, here are 5 key questions that I would endevour to answer:

1. After a training program, what could be my sustained power output capability for the event duration?

2. Knowing my power output capability, what minimum CdA / Crr (Aerodynamic drag and rolling resistance) would the vehicle need to have in order for me to set a new record?

3. What kind of track would be required?

4. What would be some other vehicle design prerequisites?

5. What kind of training would be appropriate for a 12 or 24 hour event?

1. Maximum sustained long term power

This is a very tough question to answer. I have no idea what mine would be, but I was able to find one research study published in 1984 titled “Ergogenic demands of a 24 hour cycling event.” The results of the study were published in KJ of energy and average percentage of V02 max, so with Jason Yanotas help I was able to convert his effort to an average wattage output of 200 to 230 watts.

He averaged 55% of his V02 max which theoretically should correspond to a heart rate of 70% of maximum. For me, that heart rate would be around 124 bpm which would correspond to around 160 to 180 watts.

As a second method of estimating my maximal power output, John Tetz sent me this chart:

The actual data in the original chart stops at 8 hours. I was able to plot an estimate of my own curve because I do have a few data points from my SRM training files that I was able to input. At Ironman Canada 2004, I averaged just over 200 watts for 5.25 hours during the bike leg. I could estimate that after an additional year of training, a summer of specific, heavy volume training that my 6 hour maximum output would be around 210 watts, or .28 HP. My average power output at Half Ironman California was 250 watts over 3 hours, which would convert to about .34 HP. My Maximum Aerobic power (MAP) for 5 minutes is around .36 HP. I never train my MAP, so it would be much lower in relation to my longer endurance efforts.

I used the first class athlete curve and moved it to center over my three data points as best I could. Then I extended the curves to 24 hours. According to this crude projection, my 24 hour power output could be around 186 watts (I think that’s high).

As a third method of estimating maximal power output, I used some information I received about Axel Fehlau’s 24 hour record. He averaged 42.56 kph with the M5 Carbone which I estimate has a CdA of .3 (same as the M5 #8 ?) on a 200 meter indoor velodrome track. Using the calculator, To average 42.56 kph on a very smooth track (wheel rolling resistance of .004), he would have been averaging only around 80 watts which does not seem like very much. However, the corners on the velodrome are steeply banked. I have heard that at those speeds, the corners can TRIPLE your weight. If I estimate 220 pounds total for rider and vehicle, that would put his wattage requirement at 180 watts around the corners which could be at least 25% of the entire 200 meter track. In a sense, he would have spent 6 hours producing 180 watts, and the remaining 18 hours producing 80 watts for an overall average of 105 watts (still very low!).

This may indicate that the greatest barrier to beating the record could be psychological, not physical. Theoretically, it would seem that there is ample room to improve the existing record. If I used the same M5 Carbone, on a flat track with the athlete who completed the research study at 200 watts over 24 hours, the calculator suggests that the ultimate world 24 hour record could be 1565 km – or over 65 kph average!

I would conservatively estimate the following values as my maximum power outputs:

2. What minimum CdA / Crr (Aerodynamic drag and rolling resistance)
would the vehicle need to have in order for me to set a new record?

Here is a grid that features average speeds of various drag values for power inputs of 80 to 250 watts. Match the watts input value on the grid with a CdA to reference an average speed. For comparison, the CdA values range from super streamlined Virtual Rush (.118 sq ft) to an older record breaker – the Goldrush (.5 sq ft) to the estimated drag of the current Rocket trike (1.0). There are three grids showing the effect of tire rolling resistance from average tires on a poor road surface to the very best tires on a smooth surface. Temperature was set at 70 degrees, Pres at 30″ Hg, road slope 0, no wind and 200 lbs total for rider and vehicle.

Average tires on an average road surface Crr .006

Best tire, smooth pavement Crr = .004

Best tire, very high pressure, possibly tubular,
Or, smaller tire with disc in tight fitting fairing, very smooth pavement, Crr = .0025
(Crr data for a 27″ tubular tire on pavement from “High-Tech Cycling” by Edmund R. Burke)

In a perfect world, I will build a speedbike with a CdA of .118 that will have the lowest rolling resistance possible of .0025. I will be so perfectly trained that I will be able to maintain 175 watts for the entire 24 hour event, and nothing else will go wrong (no flats, no discomfort, no breaks at all). My distance covered will be 2136 km, more than doubling the current world record!

Know what? After a career of launching and building a half dozen various businesses and other ventures, I know better than to make that mistake! Reach for the best, but plan for the worst.

If I am able to develop a fairing with an averagely good CdA – equivalent to, say, the Cheetah .3 CdA , and achieve good rolling resistance of .004, and only able to maintain an average of 80 watts for the entire 24 hour event, then my average speed should be around 43 kph which is right about on par with the current world record.

3. What kind of track would be required?

The advantages to an indoor velodrome track are the exceptionally smooth surface and no wind to interfere with the control of the speed bike. However the disadvantages far outweigh the advantages. First and foremost are the banked corners which effectively double or triple your weight as you turn them. That kind of sudden weight gain introduces additional acceleration power that is required to maintain your speed as you round the corner. The second major drawback to an indoor velodrome is it’s tiny size – 200 meters means you will almost ALWAYS be turning!

Outdoor venues consist mostly of Racetracks or vehicle testing grounds. The biggest disadvantage to most racetrack ovals is their relatively small size. A half mile going in circles isn’t all that much better than a 200 meter velodrome. Other disadvantages to a racetrack is not knowing what condition the pavement is in, and if there are any increases in elevation around the oval.

The best HPV track in the world (according to most) is the Opel high speed oval test track in Germany. It’s a 1.6 km diameter circle cut into the forest. The total length is 4.8 km (virtually, an endless straight line). The pavement is very smooth and in good condition and there is very little elevation gain. The disadvantages of the Opel track are, it’s very far away, difficult to get to and I would have to deal with the language barrier.

I found two test tracks similar to the Opel track. The first is the NCAT Pavement Test Track in Opelika, Alabama. It’s a 2.7 km long oval with very good pavement quality (Universal roughness index of 75 inches per mile – VERY smooth!) and a slight grade change of 10 feet from one end to the other.

I have spoken with Buzz Powell about using the track, and he is very agreeable. They do not run any test vehicles on Sundays or Mondays of each week, so there is a 48 hour window every single week for a record attempt.

My biggest concern is the 10 feet of elevation gain. It happens around one corner which I am told is 1900 feet long. I can calculate a slope of .5 % which would equate to an additional 50 watts required to maintain my speed going up the grade. Of course, I would make it back going down the grade, but generally any elevation change at all is less efficient in the long run than a flat course.

I spoke to the Auburn University solar car team who has used the test track in the past. They indicated that they didn’t notice the elevation change, that the track seemed very flat, very smooth, but they did notice the transition zones between various pavement test sections. I’m not sure how those transition cracks will effect my Crr. It may be worth a trip out there to do some tests and inspect the facility.

Here is a VIDEO of a drive around the track

The second track that I have identified as a possible venue is the Minnesota Road Research Project, a 4 km closed loop. The pavement is very smooth, and the track is flat. I spoke with Jack Herndon and they also are open to allowing me to use the facility. They run trucks 5 days a week, but from what I can read from the web site, the weekends seem to be available. Jack says there is a difference in elevation from the west end to the east end of 6 feet and that several sections have severe rutting and distresses.

4. What would be some other vehicle design prerequisites?

I think a trike configuration is out of the question due to the additional drag the rear trike wheels create, For me to have any chance of a new record, this vehicle must be as aerodynamic as possible. Also at the speeds I will be going, wind interference and resulting control problems isn’t as much of an issue as it is at Battle Mountain where the additional stability of three wheels could be a very important consideration.

12 or 24 hours is a long time, and I do not underconsider the importance of the comfort issues! This vehicle MUST have a large degree of seat adjustability on-the-fly. It also must be easy to enter and exit to streamline the process of taking short breaks. It must also be adequately ventilated – probably no canopy bubble with me head being cooled by the breeze.

There is a great 12 hour masters record attempt report by Ron Bobb. I spoke with Ron about his attempt and he said that it is important for the seat to be comfortable with good padding, is it VERY important to be a able to enter and exit QUICKLY. He said heat was not important, but moisture and fog buildup on the wind shield was. He had 3 IHPVA/UMCA officials and 3 crew members.

To summarize – Here is a quick design criteria list for the new speedbike:

1. CdA goal = .2
2. Crr goal = .0025
3. Must be able to adjust seat bottom up/down, seat back/fourth, upper seat up/down.
4. Must have adequate venting
5. Possibly head outside, or optional head outside (removable bubble?)
6. Two wheels – suspension probably not required
7. Average visibility

Here is a couple of sketches:

Here is how the seat adjustability could work. Basically, the entire seat hinges around the bottom bracket because that keeps the bottom bracket distance for leg length consistent regardless of where the seat is adjusted to. That would allow for various seat bottom heights. Also the seat back would rotate independently to simulated various seat angles.

The problem with this kind of flexibility are that the fairing would need to be fairly large above the knee area to accommodate higher seat positions. The area in the top of the fairing where the head pops out would also need to accommodate various seat back angles that would place the head higher or lower – visibility over the top of the fairing would definitely be an issue. I’ll need to take a much closer look at how I can accomplish both – a small, tight fitting aerodynamic fairing with some room inside to allow body position adjustments.

700 rear wheel, 650 front – almost exact same bottom bracket height, seat position, etc as the current Rocket trike. The fairing is a NACA 6xxx that is revolved with about an inch cut off of each half – then mirrored. Raymond Gage says you should never do this as it creates a hard edge which is an aerodynamic no-no

5. What kind of training would be appropriate for a 12 or 24 hour event?

According to “The Complete Book of Long-Distance Cycling” by Edmond Burke and Ed Pavelka, if you have been trained and are able to complete 10 to 12 hours of riding in a single session, then you seem to be in equilibrium and if you keep eating, drinking and stretching then very little changes as the miles go on and on. “Do things right, and you can ride practically forever”

Here is a general 8 month double century (200 mile) training program that I built using information from “The Complete Book of Long-Distance Cycling” by Edmond Burke and Ed Pavelka:

Training Phases:

1. Base Building. 4 months to develop endurance for long rides. Gradually increase weekly mileage by no more than 10-15 percent and your weekly long ride by the same. 2 endurance workouts (at least 2 hours long) per week at moderate pace.

2. Increase Intensity. 3 months to raise long distance cruising pace. Build mileage no more than 10% per month during this phase. Progressively add intensity. Twice a week continue to do long rides to build endurance. Increase the longest ride until you are at 150 miles.

3. Peak. 1 month. Keep weekly mileage the same, with one weeks long century ride at faster than planned pace, and the alternate 150 mile ride at a steady pace minimizing off-bike time.

4. Taper. 1 week – store energy for the long event.

This would put me at about late September for a possible attempt at a 12 or 24 hour record. My training schedule will probably differ somewhat because I have Ironman Idaho at the end of June which should work out as a perfect lead-up to the record attempt. I’ll be asking for a more specific training program which will include Ironman from my bike coach Jason Yanota at thebikeage.com.

There are some great training articles at the Ultra Marathon Cycling Association web site and specifically training for a 12 or 24 hour race – VERY applicable advice!

Rocket Racer to do list

1. Everything!