A rider came to me and asked about “stopping” at Wilmington.
Of all the LSR tracks in the USA, Wilmington is perhaps
the most problematic, due is parts to the uneven racing surface,
the lack of shut-down, and the solid objects in the run-off area.
So the question was a good one, and very instructive !
From the Wilmington start line to the end
of the paved runway is about 8600 feet.
Take away 5,280 for the measured mile,
and that leaves 3,320 feet to brake
before leaving the runway.
How about stopping from 275 mph ?
A skilled roadracer, like Shane Stubbs could
probably decelerate at a rate of 1.1g over that distance,
but with no “margin of error.”
A decal of 1.1 from 275 mph is a “brake to stop”
distance of about 2300 feet.
SAFE, by almost 1,000 feet……………
HOWEVER:
Let’s assume that even a skilled rider like Shane
can’t get to that full 1.1g for about 1.5 seconds after
the finish line BECAUSE, he has to “transition”
from hard acceleration to hard deceleration,
AND use his skill (which takes time) to
GRADUALLY come up on “full braking.”
1.5 seconds is about 600 feet at 275 mph.
That 1.5 seconds has reduced that “safe distance”
to only about 400 feet, which goes by mighty fast at 200 mph.
Let’s also assume that maybe Shane has a “moment”
that causes him to have to “release” the brakes for
maybe 1.5 seconds, just as he begins his hard deceleration.
At 275 mph that distance is again about 600 feet.
Let’s also assume that Shane, with at least part of his
mind on his growing family, decided to not use a “full panic”
stopping mode, and decelerated at “only” 1.0g
(Which, incidentally, is far more than most
untrained riders EVER achieve)
Shane’s braking distance is now extended from
about 2,300 feet to more than 2,500 feet.
Suddenly, Shane has run out of room, having “consumed”
1,200 feet with “transitioning,” and 2,500 feet braking.
Needing 3,700 feet to stop, and having only 3,300 to do
it, Shane runs off the end of the track 400 feet short
of a stop at about 110 mph.
It has happened there.
Several people lived,
at least one survived the crash,
and one died hitting
an obstruction in shutdown.
Skill in STOPPING is again the answer......