Home | How should I ride my Flying 200? |
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| | A junior writes that he is going to do Canadian Nationals on the Bromonte track in Quebec and wants to know if an analysis based on the Flying 200 model can offer any advice.
He rode a 12.65s flying 200 at Bromonte last year. He said that when he rode his flying 200 last season, he was a meter from the rail when he started accelerating in turn 4, crossed the start line 1 meter from the measurement line, and stayed in the center of the sprinters lane for the distance. We looked up the temperature and barometric pressure for the date as well as the elevation of Quebec and then calculated air density, 1.151 kg/m^3, which was lower than standard conditions.
Conclusions:
- Better Technique—This can improve the rider's time by 0.5s. This results from a longer acceleration before the dive and a better path. A better path will take some practice.
- More Power—(Always good) Ten percent more would improve this rider's time by 0.2s.
It's better to jump from as high as possible. It's better to stay close to the measurement line. It's better to have more power. These things are obvious. But where to jump is not as obvious. Should the rider cross wide at the start? This is not obvious either. Will doing all these things bring enough improvement to qualify? Running the flying 200 model can answer these questions.
Several of the plots at the end of this page show the elevation of the rider's center of mass. Remember that the center of mass goes down as a rider leans in a turn. Leans are dramatic on this track. Remember also that as a rider leans and the center of mass goes down, the rider's speed increases just like a roller coaster, slow at the top, fast at the bottom. This feature is often ignored in models, but it is included in this model since we are looking for very small changes.
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Here is a rendering of the 200m Bromonte velodrome as used in this analysis. The banking is steep. The track was originally a 166m track but was extended to make it 200m.
Velodrome["Bromonte Quebec"]={
- Straight=29.5,
- Radius=13,
- TrackWidth=4.9,
- CenStrBank=16,
- TurnBank=50}
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| For the base case the model uses a frontal area of 0.5 m^2, Coefficient of Drag of 0.5, Air Density of 1.151 kg/m^2, a Coefficient of Rolling Resistance of 0.004, and mass of 80 kg for bike and rider. Results could change significantly if air density on the date of competition changes. |
riderData={A=.5, Cw=.5, Rho=1.151, Crr=.004, m=80} |
| We created the power function for this rider to give a 12.637s Flying 200 on this track. Maximum power was 625w and average power was 515w. The shape of the power function is typical for a sprint. (Under ideal conditions a rider would have a recording of the power as a function of time during the effort.) |
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| Here a path for a base case. The rider jumps hard from an initial speed of 11 m/s from turn 4 from about a meter away from the rail, dives for the start line, crosses the start line one meter from the measurement line, and rides the middle of the sprint lane to the finish. |
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| The rider covers a nominal distance as measured along the measurement line of 265 m. The actual path length of the center of mass is 265.03 m. The time for the Flying 200m is 12.637 s. The time from when the rider jumps until the rider crosses the finish line is 17.786 s. |
| Length of Path relative to Measurement Line |
265.00 |
m |
| Length of Path of wheel |
271.88 |
m |
| Length of Path of center of mass |
265.03 |
m |
| Fly 200 time |
12.637 |
s |
| Total time to cover path of center of mass |
17.786 |
s |
| Length of path of center of mass in final 200m |
195.99 |
m |
| Average speed for center of mass in final 200m |
15.51 |
m/s |
| Average speed for nominal measurement line distance in final 200m |
15.83 |
m/s |
| Speed at 200m-to-go line |
15.05 |
m/s |
| Total work from start of effort |
10354. |
N m |
| Total work for Fly 200 |
3090. |
N m |
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| The rider sprints longer before the dive, dives from closer to the rail (0.3 meter instead of 1 meter) and rides the measurement line instead of the middle of the sprinters lane. |
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| This is the same rider with the same power sprinting 25 meters further but with good technique. The time improves a lot, to 12.14s. The better path may take some practice on a very steep track such as this one. |
| Length of Path relative to Measurement Line |
285.00 |
m |
| Length of Path of wheel |
297.50 |
m |
| Length of Path of center of mass |
289.42 |
m |
| Fly 200 time |
12.144 |
s |
| Total time to cover path of center of mass |
19.343 |
s |
| Length of path of center of mass in final 200m |
193.89 |
m |
| Average speed for center of mass in final 200m |
15.97 |
m/s |
| Average speed for nominal measurement line distance in final 200m |
16.47 |
m/s |
| Speed at 200m-to-go line |
15.68 |
m/s |
| Total work from start of effort |
11151. |
N m |
| Total work for Fly 200 |
4354. |
N m |
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| It's been a year. The rider has improved. Assume the rider has 10% more power. |
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| The time improves to 11.88s. More power is always better, but one has to do the calculation if one wants to know how much more power is required to quantify. |
| Length of Path relative to Measurement Line |
285.00 |
m |
| Length of Path of wheel |
297.50 |
m |
| Length of Path of center of mass |
289.36 |
m |
| Fly 200 time |
11.876 |
s |
| Total time to cover path of center of mass |
18.994 |
s |
| Length of path of center of mass in final 200m |
193.84 |
m |
| Average speed for center of mass in final 200m |
16.32 |
m/s |
| Average speed for nominal measurement line distance in final 200m |
16.84 |
m/s |
| Speed at 200m-to-go line |
15.92 |
m/s |
| Total work from start of effort |
12072. |
N m |
| Total work for Fly 200 |
4735. |
N m |
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| Should the rider start closer to the measurement line? |
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| A path crossing the start line closer to the measurement line does not help. In general one cannot tell if this will be an improvement without ruining the model. It changes based on the circumstances. |
| Length of Path relative to Measurement Line |
285.00 |
m |
| Length of Path of wheel |
297.42 |
m |
| Length of Path of center of mass |
289.21 |
m |
| Fly 200 time |
11.891 |
s |
| Total time to cover path of center of mass |
18.965 |
s |
| Length of path of center of mass in final 200m |
193.73 |
m |
| Average speed for center of mass in final 200m |
16.29 |
m/s |
| Average speed for nominal measurement line distance in final 200m |
16.82 |
m/s |
| Speed at 200m-to-go line |
16.16 |
m/s |
| Total work from start of effort |
12056. |
N m |
| Total work for Fly 200 |
4705. |
N m |
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| Here are plots based on the riding an improved path with 10% more power. |
| A plot of the elevation of the rider's center of mass along the rider's path. The rider's center of mass goes up and down as the rider leans in turns. The small slopes in the straights show that there is some slope from the center of a straight to the start of a turn, common on most tracks. |
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| Speed of the rider along the rider's path. The rider's center of mass goes up and down and this causes the rider's speed to go up and down, just like on a roller coaster. |
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| Cadence of the rider along the rider's path (49x15). A small gear is recommended for tracks such as this. |
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| Lean of the rider along path. Lean is dramatic. |
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| Lean of the rider with reference to track surface. |
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| G-force on rider. |
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| Copyright © 2000 Tom Compton All rights reserved. |