When/how to pull the chute

[fastesthonda_jim]

Folks,

My first rule of racing is, "You gotta be alive to get the trophy."

In that light I ask this question:  When and how is the safest way to pull the chute?  I prefer clutching the motor, letting the car settle, and then pulling.  Others have said, "Drive into the chute, i.e., keep your foot in it until full "wham" ".  I'm curious about the logic of this technique.

The other day I was watching video of Burkdoll's accident and it looked like the chute yanked the rear of the car into the air and the torque of the motor started the car penciling, so am favoring the settling approach.

But I am always the student so am curious.  Your thoughts, please.

All the best,

Jim Knapp

[ack]

If the back end was yanked off of the ground the chute attach point was well below the horizontal centerline of the vehicle mass.  Finding this point is very important if you are going fast.  The way the chutes are deployed on our motorcycle liner is to pull them with the power on and slowly back off the power, Sam Wheeler does the same.   My thought being that you do not want to change more than one parameter at a time at high speed.

[JackD]

Anything that pulls hard enough, low enough to lift the back will also try to make that part the top.
 In a narrow vehicle that is going to put you on your head.
A vehicle that is loose will try to snap back to center, but if it happens at the wrong time it can make the problem worse. If the chute is not correct for the vehicle, backing off first can give you the additional traction to overcome a design flaw.
Too short a lanyard, too large diameter, too quick to blossom, all can contribute to the problem.
Bike liners have an automatic deployment feature that can take the decision out of the operators hands and if properly designed can recover a vehicle from an upset and put it back up on it's wheels , straight down the road.
The design and use of the chute should contribute to the safety and is as important as anything you do.

[panic]

Anyone ever incorporated a section of bungee into the harness to reduce the "hit" when the chute opens?

[JackD]

If the chute hits too hard in a LSR application something else is wrong.
You can slow up the action by taping the lanyards together further towards the canopy and that will choke it down and slow the full opening to reduce the shock as the tape is blowen away.
Some ultra HI speed stuff will use twisted rope like material that will offer some stretch as it is loaded as opposed to the strap that can snap so hard that it or the attachment can fail.
The failure strength can be the same but a snap is like hitting a hard surface with your hand as opposed to  hitting a soft one.
Consider the chute as if you depend on it alot, because we do.

[1212FBGS]

when I was roadracing we use to say "brake when you see Elvis, if ya wait till ya see God it's too late!"

[fastesthonda_jim]

Folks,

Thanks for all the responses.  I believe my chute is attached so that when deployed the fairly long attachment line points at the center of gravity of my car.  

And yes, ack, I agree, change one parameter at a time.  Un-like Wheeler, my motor is from a car, making the crankshaft longitudinal, so I am affected by motor torque.  That's why I like to clutch the motor and go to neutral, before I toss the laundry.  I believe it makes for a "quieter" situation.

But I've only been a salt junkie for three years now and have heard more than one person say, "Drive into the chute".  I was just curious as to why.

Thanks,

Jim Knapp

[Richard Thomason]

Ed and I do differant things on shut off. I like to back out, idle for a while, click off, coast up to a mile or so and then throw the high speed chute. Ed likes to immediately throw out the chute, not necessarily drive into it but get it ou quick. Both work really fine on the Danny Boy. We spentr a lot of time setting up the chutes, both the high speed and what we call the "oh s**t chute. They have never failed us. Well I guess nI have to clarify that, we have had 2 failures in 25 years. One was at WOS when we were running a super trick Kevlar cord, supposedly good for 25000 lbs pull. It failed at the worst possible time. What we discovered was that if there was even the slightest twist in the flat cord, it would break. Ed was blown off course, hit the timing battery, pulled the chute, jerked the wheel, and went on his head. The only other failure that we have had was in around '95". I was doing a check out pass, was half way through the last mile when I felt a bang and quick decelaration. The car ran straight and continued to accelarate fine. I said to myself-no there is a problem here. Went to neutral, coasted for a while, hit the high speed chute, many times but no results. By this time I was at the 6 and 1/2. Hit the "oh s**t chute with the same results. By then I was past the drug portion of the course. We had driven in the prerace inspection to the 10 mile to check all things out. Glad we did that and will always do that, see just how far we can go if necessary. got stopped with no problem at about the 9 mile but it was not fun. What happened was that in the 4, we hit a very large hole, it bounced the chutes out of the tubes and unfortunately the tether point grenaded. Trust me me have since made sure that can not happen again. Anyway, wild rides can happen.
rht