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Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Unread postAuthor: jackssmirkingrevenge » Wed Aug 05, 2009 3:42 am

JoergS wrote:Luck? It was hard work, countless hours in the Gym.


I can imagine, I didn't assume you were born like that ;)
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Unread postAuthor: boyntonstu » Sat Aug 08, 2009 6:49 am

Ragnarok wrote:
boyntonstu wrote:Correct me if I am wrong but when a pulley is involved the speed goes in half not double.

It entirely depends on which way it's connected. Just like a 2:1 gearset can be run one way for half speed/double torque (obviously ignoring losses) and the other for double speed/half torque, pulleys can do the same.

The trick is applying the force to the pulley, and the load to the free end of the wire/cable/whatever, as opposed to the inverse (which of course, would be the normal way of doing it).

The diagram in the thread he linked would work as he suggests to double speed rather than halve it.


Back to that diagram.

Up front there are 2 fixed pulleys.

How does the rubber pull a single wire that goes across the marble?

IOW What is the purpose of the third pulley?

Thanks,

BoyntonStu
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Unread postAuthor: inonickname » Sat Aug 08, 2009 7:01 am

Well if you have a third pulley, the amount of force will be doubled again (and of course the speed halved).
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Unread postAuthor: boyntonstu » Sat Aug 08, 2009 8:03 am

inonickname wrote:Well if you have a third pulley, the amount of force will be doubled again (and of course the speed halved).



I understand.

My question is about the wiring diagram.

How does the rubber pull a single wire with oe end fixed and allow the same wire to form a loop around the marble?
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Unread postAuthor: Ragnarok » Sat Aug 08, 2009 8:10 am

While I'm here, can we make the topic title more useful than "Check this out"? There are a zillion topics called similar things, and every time I see it on the new posts lists, I keep forgetting what it actually is.

~~~~~

The pulley connected to the elastic is the mechanical advantage pulley (which has two wires running around it). This one doubles the speed.

The two pulleys at the front merely change the direction of the pull.
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Does that thing kinda look like a big cat to you?
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Unread postAuthor: jackssmirkingrevenge » Sat Aug 08, 2009 8:29 am

Ragnarok wrote:There are a zillion topics called similar things, and every time I see it on the new posts lists, I keep forgetting what it actually is.


Not me, I have the memory of an... er... one those pink things, massive! with um.. flames shooting out of them, yeah... hmm...
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Unread postAuthor: inonickname » Sat Aug 08, 2009 8:42 am

jackssmirkingrevenge wrote:
Ragnarok wrote:There are a zillion topics called similar things, and every time I see it on the new posts lists, I keep forgetting what it actually is.


Not me, I have the memory of an... er... one those pink things, massive! with um.. flames shooting out of them, yeah... hmm...


Ah yes, the "flaming pink elephant blaring out rock music wearing lead boots" innuendo lives on. :roll:
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Unread postAuthor: Ragnarok » Sat Aug 08, 2009 9:18 am

It's not an innuendo itself, but the FPE generally happens to be around when actual innuendo is...
Or whenever we're not doing what we're supposed to, for that matter.

~~~~~

Also, the best description of this forum EVAR!

jackssmirkingrevenge wrote:I love this forum, starts out as ideas for a new combustion, then in tramples a fluorescent pink elephant and before you know it, we're hunting raptors.
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Unread postAuthor: boyntonstu » Sat Aug 08, 2009 9:23 am

innuendo is... The name of an Italian Colonoscopy machine. :roll:
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Unread postAuthor: jackssmirkingrevenge » Sat Aug 08, 2009 10:12 am

A woman walks into a bar and asks for a double entendre, so the barman gives her one.


:D

Yes, this is getting silly :roll: :D
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Unread postAuthor: Brian the brain » Sat Aug 08, 2009 10:32 am

The pulley connected to the elastic is the mechanical advantage pulley (which has two wires running around it). This one doubles the speed.

The two pulleys at the front merely change the direction of the pull.


Assuming you are discussing my rubber bandgun design...
You are right, but the front pulleys also provides the " working" pulley
With a fixed path of travel.

Without the fixed front pulleys ( and the layout reversed) the string gradually pulls the pulley into the rail, wich gives a loud CLANK as I remember, not to mention wear and (counterproductive) friction..

The pulley method also ensures the rubber bands will stay in better condition as they do not wear out from the sear.
I do suggest spraying the pack of bands with some teflon spray to prevent possible friction between the bands themselves.

The bands could be hidden inside the gun body( under a cover of some sort) , so one ends up with a cleaner gun.
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Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
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Unread postAuthor: boyntonstu » Sat Aug 08, 2009 10:39 am

Image

Is this your method?
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Unread postAuthor: Brian the brain » Sun Aug 09, 2009 6:45 am

Actually..no..

I don't really get what you mean.
:roll:

Maybe I should build one again...for the benefit of this community..

Cause you all know I hate building guns... :D
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Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
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Unread postAuthor: boyntonstu » Sun Aug 09, 2009 7:49 am

Brian the brain wrote:Actually..no..

I don't really get what you mean.
:roll:

Maybe I should build one again...for the benefit of this community..

Cause you all know I hate building guns... :D


The projectile goes in he loop and it is at 2x the speed of the rubber that pulls the ring.

The frayed ends are fixed.

If it is not your method a simple drawing would help us understand your marble launcher.

BoyntonStu
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Unread postAuthor: Brian the brain » Mon Aug 10, 2009 6:06 am

Well..it's basically the idea..just..I used pulleys..and no weight...

So it seemed a little weird.
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Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
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