Is a Pneumatic hook launcher legal?

[Kevin_Crossland]

I made a pneumatic hook launcher for climbing and it works by releasing 60 psi into an aluminum launch tube(rated at 1400 psi) to propel the hook itself out of the tube. I was wondering if this launch mechanism is FRC legal?
would the launch tube need to be considered a pneumatic component as it's not holding the pressure and is just releasing it?

[pilleya]

Sadly it is illegal. To me it seems like it is operating as a single direction pneumatic piston. No custom pistons or modifications to any COTS pneumatic components such as pistons are allowed.

Also you said the launch tube is rated to 1400psi, is that tube an actual pneumatics component( ie something you purchased)?

[hrench]

Actually, it looks like a real siege weapon.

Bet that could do some damage.

So I'm calling you on aluminum tube rated for 1400 psi. Really?

[Jon Stratis]

Let me ask you... Can you imagine any situation where the hook would not launch from the tub when you release pressure into it? For example, if the hook was damaged or pressed into a wall... In that case, your aluminum tubing would not be releasing pressure, but rather storing it.

As an LRI, I would call this what it is: a custom made pneumatic device, which sadly is illegal.

[Kevin_Crossland]

darn, well thanks for your input, and yes this is the link to the aluminum tubing http://www.mcmaster.com/#89965K371 , and i guess it's not rated for 1400, but rather maximum of 1400 psi.

with my interpretation of the manual this would however be legal if I were to buy an actual pneumatic tube as the launch tube and only partially assemble it as then I would be assembling the pneumatic components using the pre-existing threads in compliance with R76 C.
"assembling and connecting pneumatic COMPONENTS using the pre-existing
threads, mounting brackets, quick-connect fittings, etc.,"

[Jon Stratis]

What do you mean by partially assemble? When buying pneumatic lost one, they come completely assembled...

What would be legal, from a pneumatics standpoint (safety would have to be evaluated separately), would be to have a COTS pneumatic piston push your hooks out of a tube. Essentially, you're separating the hooks and the pneumatics by having a COTS device contain the air and a simple mechanical interface between the piston, hooks, and tube.

[rich2202]

You can also use Surgical Tubing to provide the force to launch the hook. The surgical tubing can be held by short piston. When the piston is withdrawn, the tubing is released and launches the hook.

[jspatz1]

Originally Posted by Kevin_Crossland

with my interpretation of the manual this would however be legal if I were to buy an actual pneumatic tube as the launch tube and only partially assemble it as then I would be assembling the pneumatic components using the pre-existing threads in compliance with R76 C.
"assembling and connecting pneumatic COMPONENTS using the pre-existing
threads, mounting brackets, quick-connect fittings, etc.,"

This rule refers to assembling components into a system/network, not disassembling/assembling the components themselves. Another rule specifically states that you cannot modify pneumatic components from their original form. You can be absolutely certain that dismantling an air cylinder into an open cannon would never be allowed by a competent inspector.

[Kevin_Crossland]

Something I just realized:
I'm using http://www.mcmaster.com/#89965K371 Multipurpose aluminum tubing rated for 1400 psi @ 72° F. The manual explicitly states that

R76 A: tubing may be cut,

would this therefore be legal?

[pilleya]

Originally Posted by Kevin_Crossland

Something I just realized:
I'm using http://www.mcmaster.com/#89965K371 Multipurpose aluminum tubing rated for 1400 psi @ 72° F. The manual explicitly states that would this therefore be legal?

That is in regards to flexible plastic pneumatic tubing with a maximum inside diameter of 0.160 in. It is not legal

It cannot be "multipurpose" anything used in pneumatics needs to be intended directly for pneumatics by the manufacturer

[jspatz1]

Originally Posted by Kevin_Crossland

Something I just realized:
I'm using http://www.mcmaster.com/#89965K371 Multipurpose aluminum tubing rated for 1400 psi @ 72° F. The manual explicitly states that would this therefore be legal?

It doesn't matter what material you are making a pressurized cannon out of or how that material it is rated, you cannot pressurize homemade actuators or components. During the time the rod it traveling in the cylinder, it is a pressurized piston actuator. The rules are explicit that only rated, unmodified COTS pneumatic components may see pressure in the system.