How do you stop it?

[lvsalt]

 240mph+ motorcycle how do you stop it ? on a good run with no problems where do you turn out?
Amazing speeds, Being a car guy just wandering what the procedure is

 Gary Cole  DCWATERJET Z

[Dean Los Angeles]

You are sort of wondering how come the car guys need a parachute and the bike guys don't?

The bike doesn't way a fraction of what the cars do.

If you take the time to watch a Moto GP race (that's the F1 of bikes for you unwashed and unknowing) they stop from 200 mph in an unbelievably short distance using only the front brake. At least at the end when the rear tire is off the ground. Yes, off the ground.

On the salt it's a different story. No need to stop in a real hurry. Watch some of the Bonneville videos on Youtube it takes longer to stop than the run did.

[lvsalt]

 I think there is a big difference between 200mph and lets say 272mph. so if I understand you correctly (DEAN) it takes longer
to stop than the run, so the fast bikes are going beyond 10 miles I was thinking they would turn off around the 7 mile marker.
 By the way I understand the difference in weight between a car and a bike. Just seems like a big task getting the bike stopped to me

 Gary Cole    DCWATERJET Z

[Seldom Seen Slim]

My comments:

It might take longer IN TIME (vs. in distance) to stop a high-speed bike than a high-speed car - since the cars have 'chutes.  My experience is that I do not use the brakes at all when making a long-course 200++ run.  I roll out of the throttle at the 5 and let compression and wind drag slow me down, at about 150-160 start poking my helmet up and into the wind, about 130 start sitting up in the seat, and then start downshifting and looking for a turnout as my speed gets to a low-enough number that I can safely turn out.

Notice -- no brakes, and just slowly sitting up.

By doing that I've seldom gone past the 6 before starting the turnout. 

At higher speeds the distance traveled before the turnout might be larger -- but also, the available wind drag forces will be higher so they'll be more likely to slow the bike in time for a relatively quick turnout.

Going past the 7 would be a huge surprise to me -- even at 250++ speeds.  But I will admit that I'm quite a ways below that 250 number -- maybe those that have run so fast will have other responses.

To summarise -- no, it's not likely to have a bike go farther than might a car after finishing a run.

[McRat]

I'm not an LSR bike racer, I've just raced and rode bikes at mild speeds:

Lightweight and high Cd probably goes a long way towards scrubbing off speed even without brakes.  Not a math guru, but if it takes 400+ HP just to push through the air, when you lift, there is 400HP worth of resistance against a ~700lb package.  The decel should be well over 1 g at first.  I know when you chop the throttle after a drag pass, the bikes slows rapidly even at only 135mph.  Even when I ride a bike on the freeway, it decelerates much faster than a car when you grab the clutch.

[lvsalt]

 Thanks SSS that is the type of responce I was looking for.

 Gary Cole  DCWATERJET Z

[Wester]

I think Nancy's experience of having he foot slip off the peg at over 200 should enter into this discussion.  It kept her from a faster time and was enough of a distraction to slow her as well.  Joe Amo could tell you how important the tuck is but also how much help he received from the rules that allowed some additional body at the rear of his bike.  Nancy was constantly thinking of ways to improve her aero "egg" too.  I have heard many stories from racers on streamlined body bikes about how the air flow can bother the bike in little ways.

A perfect example of this is the little clamshell at the back of the 444 car that is the first airflow interruption on the car.  Like the larger clamshell on the Burkland's 411 car, that air brake bleeds off a LOT of speed before their chutes are deployed.  Can you imagine what would happen of a bike rider sat up abruptly at 200 mph? 

[mkilger]

like Slim, you can slow by going into the 5 mile marker and then turning ouch I mean out.

[Freud]

I can tell you what happens at 180.

I did a plug chop and immediately sat up after that run. I mean     IMMEDIATELY.

There was no front brake and we had bled off all the fluid on the rear caliper because it was dragging. Previously I would roll off the

throttle, clutch squeezed and wait until it had coasted down.

This time, I just popped up. It took my breath away, rocked my head back some and really slowed down rapidly. I just took a big right turn, that was

the way to the return road, and continued to coast. The back end would "step out" each time I ran over a pressure ridge. That was a HOOT.

I was off the track and stopped in a half mile from shutting off. I was a mile closer to the starting line than was my pick up driver.

I didn't think it was in anyway a big deal. Road racers do it many times per lap.

Anticipation was a bigger deal than the happening.

FREUD

[4-barrel Mike]

That sounds really entertaining.  I hope you got lots of pictures.   

Mike

[Seldom Seen Slim]

I don't remember what thread it was on - that I said I'd like to have a discussioin/dissertation on parachutes for land speed racing.  If someone will please let me know -- I've got further to add now, but I want to do it in the right place.  Lemme know, hey?

[McRat]

You made the request in the Shootout thread.  Somebody wanted to get ahold of Bob Stroud and talk him into writing up something to get it started.

[Seldom Seen Slim]

Thanks, Pat.  Okay -- I'll mention what I've got to say over in Shootout - then will sooner or later start a thread on chutes in LSR.