Aerodynamic vs. vehicle stabilty

[hotrod]

I take pictures on the long course near the 2.5 mile and sometimes I get lucky and catch chutes just as they are clearing the pack.

These pictures might be useful for discussion sake.




(and yes the chute deploy on the 6050 car was taken as your hood blew off!)


Larry

[saltfever]

Great pics, Larry. It sure demonstrates Blue's point of view about dirty air. Many thanx. 

[jl222]

  The air couldn't be dirtier than behind a funny car and they work quick and well, proven many times over LSR racing and at higher speeds than most with a shorter stopping distance.


            JL222

[hotrod]

I guess the relevant question is then, what is the difference between a typical chute and one intended for use on a funny car?

Larger drogue, longer line on the drogue, stronger spring, different method of packing or release???

Larry

[1212FBGS]

Yes Blue i have stepped on the salt at the 7mile.... actually most recently a couple weeks ago when i was getting out of my race car.... can you say that?
about them chute pix... before you guyz get yer panties all in a knot, just remember 1 thing ole Blue isnt sharp enough to figger out... that chute is travelin as fast as that car is! ever toss a beer can out of a movin car? The only thing you need to worry about is if the chute gets out or not!.... period!
We dont have a net and kitty litter box closin in fast....
kent

[SPARKY]

Kent  ,  the air its going through isnt moving at the vech speed

[F104A]

In 2004 I began using a deployment bag in the lakester. I use a kicker spring to send the bag out and a
pilot chute to continue the pull until the riser line reaches full extension. At that time, the bag strips off
and the chute is allowed to stretch its lines then opens. My riser line is 3 times the length of the lakester.
I get no chute flying around, no yank, and the chute floats about 2 feet off the salt at 230 MPH.

On the Eagle, I use a 150 ft multistand plasma riser line, rated to 52,000 lbs. My chute will exert 47,000 lb
at 750 MPH. I also sew a cotton sleeve over the length of the line to prevent chaffing or burning from being
dragged on the ground when slowing down or during the initial opening of the chute. My kevlar parachute is
pressure packed into a deployment bag. The reason for pressure packing is to minimize the loss of energy when
the chute bag is fired out with an air charge. I also use a pilot chute to keep the bag oriented during flight.
The bag has assister pockets sewn on the outside to grab air which helps with it stripping off the chute when
the riser line reaches full extension. The parachute lines don't open instantaniously because I tie cotton
line around the lines at intervals to make it stretch the lines all the way out before the chute can begin
to open. Our films have shown that getting the chute way out into clean air makes it open quite smoothly
and it floats about 3 ft off the dirt. Our chutes are made of kevlar panels, lines and thread. So far, they
have worked as designed.

[tortoise]

The only thing you need to worry about is if the chute gets out or not!.... period!
We dont have a net and kitty litter box closin in fast....
kent

Don't you believe in the value of quick deployment to straighten a car starting to get sideways?

[John Burk]

"Yes Blue i have stepped on the salt at the 7mile.... actually most recently a couple weeks ago when i was getting out of my race car.... can you say that?
about them chute pix... before you guyz get yer panties all in a knot, just remember 1 thing ole Blue isnt sharp enough to figger out... that chute is travelin as fast as that car is! ever toss a beer can out of a movin car? The only thing you need to worry about is if the chute gets out or not!.... period!
We dont have a net and kitty litter box closin in fast...."
kent

A good deed never goes unpunished .
John Burk

[F104A]

If my car gets sideways, no record anyway. Just clutch it, steer into the direction you want to go. If that doesn't work, let go and look at the floor, otherwise you could get dizzy. If you're using the chute to keep your car straight, you have bigger problems.

[jl222]

If my car gets sideways, no record anyway. Just clutch it, steer into the direction you want to go. If that doesn't work, let go and look at the floor, otherwise you could get dizzy. If you're using the chute to keep your car straight, you have bigger problems.

  Are you saying don't pull the chute to keep from spinning, just let it spin?

              JL222

[jl222]

The only thing you need to worry about is if the chute gets out or not!.... period!
We dont have a net and kitty litter box closin in fast....
kent

Don't you believe in the value of quick deployment to straighten a car starting to get sideways?

  Thats why I like the funny car type pilot chute and short lines [like lakester in bottom pic as to long pilot chute lines on camaro and black roadster.
   I wouldn't consider F104's advice for 1/10th of a sec.

           JL222

         

[1212FBGS]

Don't you believe in the value of quick deployment to straighten a car starting to get sideways?
[/quote]


quick deployment doesn't mean squat... up in the air, out the back its still out! now if yer concerned about it hitting quicker, that's all about riser length, bags, tape, rubber bands, etc not about popping the pack into air stream... Short risers and big chutes are great for stopping on a short shut down (1/4 drag strips and paved miles) but can upset a LSR car on a loose course... if your worried about catching a spin, put a small "oh shoot chute" on it
kent

[jl222]

Don't you believe in the value of quick deployment to straighten a car starting to get sideways?

quick deployment doesn't mean squat... up in the air, out the back its still out! now if yer concerned about it hitting quicker, that's all about riser length, bags, tape, rubber bands, etc not about popping the pack into air stream... Short risers and big chutes are great for stopping on a short shut down (1/4 drag strips and paved miles) but can upset a LSR car on a loose course... if your worried about catching a spin, put a small "oh shoot chute" on it
kent
[/quote]

  Take a look at the pics and the long pilot chutes lines, the long lines are just delaying the opening. Why? If I don't want the chute open at shut off [Bville] I wait a while then open but if in trouble I want it open instanly.
 

                JL222

 

[Glen]

Ask a dozen people and you will get a dozen different answers, with no two vehicles alike and mountings different plus other conditions it's hard to agree with anyone. From my seat I have seen many conditions with chutes and when something is unusual I always try to let the crew know as well as Lee and Steve.