Grade of Aluminium for handle

[Stainless1]

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

I have to call Johnboy tomorrow for his Birthday (we are only the same age for 6 days a year) I'll see if he can go down to the shop and snap a pic or two.  I'll look through my pics, I may have one, chute is in a tube on the lakester, but the concept could easily apply to the chute in a pack since they both pull a wire.

[836dstr]

Thanks Stainless,

For a while I was running a Stroud Chute popper but never really needed it because the standard spring and pilot chute worked fine. I still have the CO2 bottle I could use.

Tom

[Blue]

Material isn't as important as design, applied force and safety factor.  For most structures, a 1.5X safety factor vs. maximum load (hard bump at full speed) is used, 2X for composite structures.  For safety critical items this goes up.  On the Fossett LSR, we use between a 4X and 20X safety factor on primary safety items like the parachutes and brake.

Since this is a handle that you will pull on, potentially when some thing is going badly wrong, it should be stronger than you are regardless of what it's pulling on besides you.  For a seated person, a one handed pull limits out at 75 to 250 lb. depending on the person.  If the handle can take a 1000 lb pull without bending, it's probably OK.  So build it and hang some serious weight on it.

This sounds crazy, but a P-38 pilot once dove too hard and ended up pulling out with both hands on the stick and his feet on the dash.  The stick bent at 2200 lb.  The stick bent, didn't break, and he made it.  So that's the standard for controls.

[836dstr]

Hey,

The thought just occured to me that there are some serious design or installation problems of the chute release system if more that a few foot pounds need to be applied to an aluminum handle even if slammed or pulled frantically during a chute release. Mechanical linkage might be more of an issue, but a simple Morse cable, unless with very tight bends, should not take much force to actuate. Am I missing something?

Tom

[edweldon]

Hey,
The thought just occured to me that there are some serious design or installation problems of the chute release system if more that a few foot pounds need to be applied to an aluminum handle even if slammed or pulled frantically during a chute release. Mechanical linkage might be more of an issue, but a simple Morse cable, unless with very tight bends, should not take much force to actuate. Am I missing something? .......Tom

Don't forget the scenario where someone, driver or crew member, steps on the handle accidentally entering or exiting the cockpit some time between the end of the run and the time the chute gets repacked.  This isn't as unlikely as it sounds.......  As with the P-38 stick case the worst loads for design are often due to some combination of Murphy and the "human operator" (or a member of the maintenance crew.)
Ed Weldon

[836dstr]

Ed,

Point well stated. I was thinking of my Roadster where all of the controls, switches, chute release are mounted off the shoulder bar on the right side of the steering wheel, and out of harms way.

I can see where in a laydown car like a streamliner or lakester that the controls are more at risk than a roadster where entry and exit are more straight up and down.

That's what I love about this Forum, it expands your perspective and knowledge.

Tom

[Howard]

I forgot how lucky I was with my liners. They went so straight that when I got in top gear I just steered with my left hand and put the right hand on the chute release. Can't do much steering on a skinny liner anyway unles you want a very erratic and rapidly changing view of the scenery.
Howard