Well, we've talked about getting up to speed in a mile...how about a discussion about the other half...stopping.
There have been some concerns posted on a couple of other sites about the stopping distance available at the Colorado Mile.
The runway at Front Range airport (KTFG) is 8000' long. There are no overruns or underruns (“extra” pavement at the end or beginning of a runway that’s often useful in emergencies – or used as a “safety zone” when you really want to pack as much as you can on an airplane to make as much money as you can…), so there’s no additional length we can use for our car or motorcycle at this event. So, 8,000 – 5,280’ (the mile long race course) = 2,720’ or about 80’ more than a half mile. Since this is a marked out 1 mile and you have to have at least SOME room to line people up (and you aren’t allowed to “roll onto” the track) – for the sake of discussion let’s say that “extra” 80’ gets used for staging. We’ve got 2,640’ to get stopped in then. Or maybe not – you really don’t need to be completely stopped by the end – you really only need to slow down enough to make the turn off…let’s call that 30 mph? Maybe 20 mph? After a good high speed blast that will probably feel slow enough to think you could pop down the side stand and just walk away at that point!
How long does it take to slow down from speed? Mr. Scott Guthrie (google him – he knows a thing or two about going fast and getting slowed back down) had a good reply on this over at hayabusa.org. Here is a shameless cut and paste from there:
[NOTE – this discussion was based on the use of a shorter airfield in another country for a ½ mile event and would only have ¼ mile for the shut down area]
"A good answer can be easily calculated with a little simple arithmetic.
1) Assume you will travel at least an additional 1/2 second
before you can get on the brakes hard.
1/2 second is pretty quick, since you would not want to "hammer "
the front brake, and skid the front tire........
a) at 200 MPH, 1/2 second about
equals 1.466 x 200 x 0.5,
so about = 150 feet.
2) From 200 mph, a MotoGP rider, on typical runway pavement,
could probably achieve a reliable deceleration rate of f = 1.2.
A skilled rider, would maybe develop f = 1.0 decel,
and a typical street rider would achieve f = 0.8 decel.
3) One can use a standard formula to calculate stopping distance from a known speed.
a) Distance (d) about equals the speed (S) squared,
divided by the deceleration factor times the constant 30.
b) d = S squared / 30f.
4) Examples:
a) stopping distance from 200 mph if you are as good as a MotoGP star.
a1) d = 200 squared divided by 1.2 PLUS the "reaction" distance of about 150 feet.
a2) 200 squared = 40,000
a3) 40,000 / 1.2(30) = 1,100 feet of decel.
a4) add the reaction distance of 150 feet
a5) stopping distance for the MotoGP rider is 1,250 feet.
b) For the "skilled" rider the total stopping distance
about equals 1,350 + 150 = 1,500 feet
c) for the average rider, the total distance = 1,650 + 150 = 1,800 feet.
5) Assume you have 1/4 mile of paved shutdown, which today = 1,320 feet.
a) The MotoGP man stops with 70 feet ( 3 - 4 car lengths) to spare. Are you that good ?
b) The "skilled guy" needs 1,500 feet, but has only 1,320 feet.
b1) 1,500 - 1,320 = 180 feet.
b2) "Skilled guy" goes off the end of the track at about 75 mph (reverse calculation)
c) "Average guy" needs 1800 feet, and goes into the dirt at almost 110 mph
c1) Think about riding your 'Busa' at 100 in soft dirt, with trash and stumps...."
The late Bill Warner shows the perils of going a bit fast for the course on a 278 mph run (HOLY CRAP!) at the Texas Mile. For anyone that doesn’t know – Bill Warner set the all time speed record for a sit-on bike at 311 mph at Loring Maine.
http://jalopnik.com/5708174/ride-to-2786-mph-with-the-worlds-fastest-streetbikeBottom line of all this? That ½ mile should be “plenty” of stopping room – even if you allow for a second and a half to roll off the throttle and ease into the brakes. The critical part is to begin slowing at the line and not run through it too far. Most of the accidents at these 1 mile courses occur when someone “zones out” going past the 1 mile markers and don’t start slowing or are so focused on keeping their head down they miss the marker or get distracted watching the tach or a GPS speedo they miss the markers. So, “plenty of room” – just not much room for mistakes!
