Vacuum cannon for line launching?

[Webfoot]

Boy I feel dumb. I forgot about the line itself. I can't see how that could fit into this.


This is like the functional hybrid of a Big Shot and a classic spud gun. Could it work for line launching? If shots are made upward it should be possible to brace the cannon on the ground. The second design has a cord pulling back the piston and a magnet to hold the projectile. How could this be made ergonomic to both aim and pull the cord at the same time?

Pros: simple design, no pumping, no pressure chamber, no possibility of an accidental discharge

Cons: no trigger, disposable burst disks, long barrel as max pressure delta is 1 bar, no place for the throwline (dumbass!)

 

[Webfoot]

It occurs to me that a spool could be put inside the piston but that would introduce an additional volume of air that would probably make the whole thing inefficient.

 

[Phil]

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Buy one of these. Find a way to fit a PVC or similar tube to the end of the silver air chamber. Tube holds throw ball. Use pressure gauge to dial in line launch height. Install red dot sight. Charge, aim, fire, climb.

 

[moss]

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Buy one of these. Find a way to fit a PVC or similar tube to the end of the silver air chamber. Tube holds throw ball. Use pressure gauge to dial in line launch height. Install red dot sight. Charge, aim, fire, climb.

That looks highly possible ;-) So explain again why you want to fire a throwbag into a toilet?

That looks really good. would be nice to rig it with a battery pack. And/or a hand pump valve add-on.
-AJ

 

[moss]

So much time and effort has been put into various air cannon designs for tree access/line setting, worth iterating from there for sure. Tree Stuff's APTA has weird features like a zip-tie attached handle and still uses (as far as I know) a simple lever arm/ball valve release. Nevertheless it is "state of the art". In particular it uses an aluminum barrel/compression chamber instead of PVC pipe. It's clearly more durable and less bulky for regular use than PVC

There has to be a better a better release valve/trigger system for strong aiming technique like you'd expect with a bow or rifle, probably is, haven't seen it.

All that said, slingshots rule ;-) I've never weighed my pole and slingshot system, but I've backpacked it plenty and it's quite a bit less than the 7.5 lb. APTA.
-AJ

 

[moss]

It occurs to me that a spool could be put inside the piston but that would introduce an additional volume of air that would probably make the whole thing inefficient.

Throwline should always be outside of the cannon barrel no matter what the propulsion system is.
-AJ

 

[Webfoot]

Throwline should always be outside of the cannon barrel no matter what the propulsion system is.
-AJ

What's the reason for that other than the already stated problem?

 

[Matias]

What's the reason for that other than the already stated problem?

I mean, you could maybe fire the first shot right off a new spool, but what about after that? How do you keep the line from becoming a rats nest?

 

[Webfoot]

I mean, you could maybe fire the first shot right off a new spool, but what about after that? How do you keep the line from becoming a rats nest?

I guess it could be wound up again first. Is that the only reason? moss' definitive statement alludes to something else.

None of that is practical and defeats any simplicity of the vacuum cannon concept for this. It's just theory.

 

[Matias]

I guess it could be wound up again first. Is that the only reason? moss' definitive statement alludes to something else.

It feels like it may be about something more, but any system that has me hand winding up to 200' of throwline per shot is a deal breaker for me. Unless you have some kind of reel to wind it up quickly, but if that reel operates from within the chamber, then this is all getting pretty complex pretty quickly...

 

[moss]

I guess it could be wound up again first. Is that the only reason? moss' definitive statement alludes to something else.

None of that is practical and defeats any simplicity of the vacuum cannon concept for this. It's just theory.

My comments on where throwline should or should not be are based on many years of handling throwline. Experiential practicality.

It’s worth playing around with conventional tree access techniques with throwlines and weights, you’ll get a sense of what the real-world gotcha’s are. It’s challenging to innovate without knowing what the practical problems are.
-AJ

 

[moss]

What's the reason for that other than the already stated problem?

Every aspect of throwline management, including firing with lowest chance of throwline snarls during the throw, is enhanced by keeping the throwline separate from the throwing mode (human arms, large slingshot, or throwing cannon).

For a cannon device with any of many possible forms of propulsion, the throwbag/round is positioned in the cannon barrel, the throwline trails out the end of the barrel.

This is practical from the perspective of throwline management in between throws and minimizing reloading time.
-AJ

 

[moss]

In my analysis of practical throwing efficiency I’m not talking about two-step throwing processes using fishing line, open-face reels, and crossbows or small hand slingshots.
-AJ

 

[Bart_]

Moss beat me to it sort of. I was going to mention researching existing methods of both line management and projectile launch. Check out twist in line re open face spool reels and the sidewinder(?) line winder upper. Arborella optional.

 

[moss]

Moss beat me to it sort of. I was going to mention researching existing methods of both line management and projectile launch. Check out twist in line re open face spool reels and the sidewinder(?) line winder upper. Arborella optional.

Apologies, I had a moment of free time ;-)

 

[moss]

I had a friend who designed a unique system for firing a line from a ship to rescue a “Person overboard!” Or to fire a line to a vessel in distress, or for any other reason. I wish I could remember the details, it was 50 years ago ;-) I was impressed by the innovation. I don’t know if it went into practical use. It did require a serious mounting system and some sort of explosive charge ;-)
-AJ

 

[Webfoot]

I don’t know if it went into practical use. It did require a serious mounting system and some sort of explosive charge ;-)
-AJ

In that vein we could skip the throwline and use a trebuchet.

 

[Bart_]

winter and throw line = IIRC
also skinny vs meaty is an issue - on bark, drag weight, drop weight

sidewinder is lanyard spooler - wrong name. I can't remember the name of - big spool, lay it on ground and fire/deploy directly off it (?)

 

[moss]

winter and throw line = IIRC
also skinny vs meaty is an issue - on bark, drag weight, drop weight

sidewinder is lanyard spooler - wrong name. I can't remember the name of - big spool, lay it on ground and fire/deploy directly off it (?)

Those big hand spools might be from kite flying.

So far nothing has taken hold to dethrone the throwing cube.
-AJ

 

[Tom Dunlap]

Tree Machine aka Jim Clark, in Indianapolis, made a throwline reel.

throwline reel

Throwline reel Thanks to treemachine, I had to try this out. Not as refined as his, but I can always refine it later. My reel pictured with my repaired big shot that works just fine: http://i627.photobucket.com/albums/tt356/papacodes/Tarzans%20Tree%20Service/09291631.jpg Fired a shot of...

www.treebuzz.com