Grade of Aluminium for handle

[DCarr511]

I'd like to know if there is a minimum grade aluminium to use for a parachute release handle.

I looked in the 2007 Rule Book and didnt see anything about it.

Does anyone have anyinfo on this ?

TIA

[Stan Back]

Duane --

That's the beauty of the SCTA Rule Rook.  You can make it to the specifications you think will do the job.  Even a little bit more.  And the inspectors will evaluate it and determine if it does the job.

Remember -- weight is not usually you enemy -- so make it stout, make it so will trust it -- and it will almost certainly pass muster.

Stan Back

[Sumner]

I'd like to know if there is a minimum grade aluminium to use for a parachute release handle.

I looked in the 2007 Rule Book and didn't see anything about it.

Does anyone have any info on this ?

TIA

If you mean the one you pull with your hand, I would doubt it.  Most of that kind of stuff they leave up to the builder, but I imagine anything on the car could be questioned if it looks iffy and especially if it could effect safety,

Sum

[edweldon]

99% of the plate you'll find will be 6061-T6 which is fine and easy to cut.  1/4 to 3/8 thick is good for a chute handle  Steel plate would work also if you live in one of those parts of the country where the your choices in aluminum are cooking foil, soda cans, roof flashing and old frying pans.  But aluminum is a bit easier to cut and shape unless you are like me when I first started building hot rods.  My "power" tools back then were an acetylene torch, body grinder and a 1/2" electric hand drill. A nice band saw to shape an aluminum handle was a far away dream.
Just remember that the aluminum in old frying pans is pretty well annealed; so it bends a lot easier than stock 6061-T6.  Test the finished handle by slamming it as hard as you can, standing on it and whatever else you can think of.  'Cause a day can come when it'll be tested that way when you least expect or want it.
Ed Weldon

[Stainless1]

I would like to suggest that the handle you are building is just the backup for the electric release button that is mounted on your steering wheel, reachable without moving your hand position.  Can be air or electric release, but the ability to release the chute without taking your hands off the wheel is invaluable.  The first time we had a loss of control at 200+ incident Johnboy went around a couple of times before he could get to the chute release handle, before the next season we added electric actuation.  The quick release has saved the car 4 times since then, including my 220 spin that had the car with 1 wheel left on the ground when the chute caught it. 

[edweldon]

Eh Stainless -- That's a pretty good endorsement for a chute release button on the steering wheel.  How about sharing mechanical details?  Especially how you made the electrical release and the backup mechanical handle an "either/or" setup.
I'd also throw up for discussion the question of the relative merits of doing it electrically vs. pneumatically with a CO2 cylinder like they use in paintball guns for the energy source.  Comments anyone?
Ed Weldon
Captain Eddie's Day Old Fish market - Home of the Bonneville Salt Fish
Featuring the miracle of modern mechanical refrigeration.
Los Gatos (on the far side of the mountain), CA

[Glen]

I used a air release system when I was drag racing, made my own worked great. Stroud safety sells a couple of systems. look him up on the internet.

[Stainless1]

Eh Stainless -- That's a pretty good endorsement for a chute release button on the steering wheel.  How about sharing mechanical details?  Especially how you made the electrical release and the backup mechanical handle an "either/or" setup.
I'd also throw up for discussion the question of the relative merits of doing it electrically vs. pneumatically with a CO2 cylinder like they use in paintball guns for the energy source.  Comments anyone?
Ed Weldon

If you use a paintball cylinder, keep it cool or the burst plug will go and you won't have the pressure.  It is hot out there.
We use a GM door lock to pull the pin with a cable pull as the backup.  It is hot wired so it has power unless the master switch is off.  The pin is hard attached to the lock slider and has a piece that the cable passes through and allows the part to slide over the cable, cable has an end stop.  When the pin is locking the chute, it is also against the cable end.  When you punch the button, the door lock pulls the pin, sliding over the cable, if it does not operate, pulling the manual cable will pull the pin. 
From start to finish on my incident, was 500 feet.  That is from where the rear wheels lost traction and started moving off their straight track to the big blue paint mark where the front of the car slammed back down on the ground... about a second and a half total time at 220, never be shy about putting out the chute.  If you think you are losing control, you are... the quicker you get the chute out the better off you will be.

[Sumner]

.................  If you think you are losing control, you are... the quicker you get the chute out the better off you will be.

Yep, I second that, better to go back and get in line with a car and driver that is one piece than to go home with hopefully only a broken car.

I'm following Stainless's lead on this and going to set my chute system up very similar.  Hooley must have very fast hands as I don't know how he has gotten his hands up to the chute release as fast as he has in the past.  Mine aren't that fast, there will be a button there for me with a backup,

Sum

[DCarr511]

Thanks for all the answers and some real good advise !!!

[Glen]

I have seen a couple of MC cast alum.( clutch levers)  chute releases break. Last year a rear engine modified roadster spun at the 3 miles and the driver pulled on the steering wheel and it broke in 3 pieces. Again cast alum. I have pictures of the steering wheel that was out of the car and pieces on the course. Just be careful what you use.

[edweldon]

One other comment on chute releases.  Not that this is necessarily the best thing....
Doug King had the chute release lever in the Goldigger lakester set up to close the fuel shutoff valve also when it was actuated. The fuel shutoff could still be actuated independently. It all was about 6" from the driver's left hand. Far enough away from the action that it was pretty unlikely to be accidentally actuated once the safety pin was pulled.
That was a 190 mph car and was pretty stable.  Doug only spun it once on some wet salt.  Except for that time it never really scared any of us. 
Ed Weldon

[edweldon]

I just reread Glen's post about the casting flaws in clutch levers and it got me to thinking.
6061-T6 wrought aluminum plate stock in thicknesses in the range 1/4" to 1/2" thick is pretty reliable stuff.  At Beckman instruments we used it for some pieces of centrifuge rotors in the lower speed ranges 30,000-40,000 RPM.  These things would explode in the centrifuge from centrifugal force if they had metallurgical flaws. Every one was tested to maximum speed and load.  Every once in a great while we'd get one with a metallurgical flaw, usually a long stringer from the process of rolling the aluminum plate at the mill.  You couldn't see it during the machining; but as soon as the part was clear anodized a flaw would show up as a faint darker line under the anodize in what should be a uniform surface of the part.  The guys on the test floor were tuned in to this because they had to do the repairs when a test machine was damaged.
 But the bottom line really is that if your aluminum plate has the markings of one of the US or Canadian aluminum companies on it you're likely OK.  And by the way, the 2000 and 7000 series "aircraft" aluminum alloys aren't the best choices for stressed parts with long time exposure to salt and moisture, even when anodized.
Ed Weldon

[836dstr]

Stainless,

Could you post a picture of your chute pack and release mechanism?

I'm trying to visualize it. Sounds like a good idea!

Tom

[Sumner]

Stainless, Could you post a picture of your chute pack and release mechanism?

     

He did, he has been trying to find a place to develope the film  ,

Sum