Human-Powered Vehicle Speed Competition 102
nsasch writes "Over at Battle Mountain, NV on SR-305, for the 2008 Battle Mountain World Human Powered Speed Challenge (mirror), some of the best cyclists will be competing in human-powered vehicles to break speed records. The current world record was set in 2002 at the same location with a speed of 129.6 km/h (81 mph) by Sam Whittingham in a custom-made recumbent bike. A lot of advanced aerospace engineering goes into these machines to reach highway speeds on less than one horsepower. Take a look around their site for pictures of the event and this year's records. It ends 20 September, so more pictures and results will be coming."
Re:Not at sea level? (Score:2, Informative)
Re:Not at sea level? (Score:5, Informative)
This is the longest, paved, straight, flat stretch of road that the organizers are aware of, in the US. Also, Nevada lets them shut it down for certain time windows for the race.
If you do the race on a banked racetrack you can get an advantage from the wind where you use the bike fairing as a sail. That wind assist is hard to calculate and factor out of the final time, while a small headwind or tailwind on a straight course is easily mathematically removed to be able to equalize the results.
More than one Horsepower (Score:1, Informative)
The records will probably be set using much more than one horsepower - Cyclists are easily able to exceed 1kW peak power.
An egyptian locomotive? (Score:3, Informative)
As Mark Twain put in his "Innocents Abroad", the Egyptians burned mummies in their locomotives: "The fuel is composed of mummies three thousand years old, purchased by the ton or by the graveyard for that purpose, and sometimes one hears the profane engineer call out pettishly, 'D--n these plebeians, they don't burn worth a cent--pass out a King!"
Re:Not at sea level? (Score:2, Informative)
If you do the race on a banked racetrack you can get an advantage from the wind where you use the bike fairing as a sail. That wind assist is hard to calculate and factor out of the final time, while a small headwind or tailwind on a straight course is easily mathematically removed to be able to equalize the results.
"Legal" runs through the 200 meter speed traps must be made when the wind is below a certain speed (defined in the IHPVA rules, along with allowable downgrade for the road and various other conditions). There is no correction done for head or tail wind.
Re:Not at sea level? (Score:3, Informative)
Since power required to overcome air resistance rises as the cube of the speed (force rises as the square, as a function of the cross-sectional area) there's a big advantage to high elevation. Since power produced drops off roughly linearly(*) with elevation because of reduced oxygen for the rider, you gain more by going to higher elevations than you lose. Many long-standing Olympic cycling (and other speed-related sports) records were set at the 1968 Olympics in Mexico City, at 3200 meters elevation.
* as I recall, pressure drops off as an exponential function, roughly pressure = sealevel pressure * e ^ (temp / (acceleration of gravity * height in meters)) but don't quote me on that.
Re:Recumbents (Score:2, Informative)
Not sure if you were kidding with that line, but a movie was made about him.
The Flying Scotsman [imdb.com]
Re:More Information on the event... (Score:2, Informative)
What makes Battle Mountain the place to do this kind of thing is it's the smoothest, flatest road that the local community is willing to close.
Actually, it is not flat and has the steepest slope permitted under the ihpva rules for the 200m record. Unlike other forms of land speed record you don't have to do both directions, as in general the riders are only able to do one good run each day.
This is a bit of a cop-out though, as even the miniscule slope permitted under the rules becomes significant at high speed. Look at it like this - if you weight 100kg and drop 1m you gain 1kj of energy.
A gradient of 1/100 is nothing if you're pootling along at 4m/s, but if you're doing 40m/s it starts to provide a significant amount of your energy output. If Battle mountain were truly flat, the records would be significantly lower - perhaps 70-75mph.
Sam Whittingham's Bike Design (Score:4, Informative)
I didn't see it mentioned in the summary, but world speed record holder Sam Whittingham's bike [thetyee.ca] was designed by a Bulgarian sculptor, Georgi Georgiev, who is not an engineer. The bike was not designed from computational fluid dynamics, or other modern engineering techniques. The design emerged from the brain of Mr. Georgiev; he designed the bike to "hide from the air", while providing Sam Whittingham with just enough space to pedal comfortably.
I have always been amazed that Sam Whittington and Georgi Georgiev have been able to consistently beat teams with engineers and batteries of computers with advanced aerodynamics software. Mr. Georgiev is something of a genius.