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surprised by a ball valve! Massive kick and thump.

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: Ragnarok » Mon Jul 05, 2010 1:08 pm

velocity3x wrote:Nothing will come close to the superior performance of a powered ball valve.

Exactly. Go valveless. :tongue3:
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Does that thing kinda look like a big cat to you?
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Unread postAuthor: jackssmirkingrevenge » Mon Jul 05, 2010 1:41 pm

Ragnarok wrote:Exactly. Go valveless. :tongue3:


Since velocity3x uses solid rounds, this might be an option he might want to consider ;)
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Unread postAuthor: maverik94 » Mon Jul 05, 2010 2:29 pm

I like shooting my .243 due to the fact that at that caliber, ammo is still affordable... and the accuracy of this rifle is simply insane.
(New England Firearms .243)

Don't get me wrong. I have nothing against small caliber guns! Nothing beats them in plinking, target shooting, and small/medium game hunting...and ammo is dirt cheap.
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Unread postAuthor: POLAND_SPUD » Mon Jul 05, 2010 3:35 pm

Exactly. Go valveless
I hear ya :wink:
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Unread postAuthor: velocity3x » Mon Jul 05, 2010 8:01 pm

Technician1002 wrote:Steel spheres are a high mass projectile and will work fine with slower valves. Lighter projectiles need the advantage of faster valves more than heavy projectiles.


I guess it's a matter of what you consider to "work fine". IMO, there is the lethargic (work fine) performance, then there is high performance. Personally, I prefer the latter. Everything (heavy or light) performs better with speed. Heavy projectiles are no exception.
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Unread postAuthor: Technician1002 » Mon Jul 05, 2010 11:02 pm

There is a point of diminishing returns where fast is fast enough. Marshmallows do fine with valve speeds under 1ms. A steel ball will get about the same distance traveled in the barrel with a valve that opens in about 8 ms. With the same pressure the steel ball will accelerate slower.

My video on the QDV covered the valve speed as a function of projectile travel in the barrel, not in time is seconds. The higher the pressure the faster both are. The lower the pressure, the inverse is true. For high performance I like the valve fully open before the projectile has traveled it's diameter in the barrel if possible. A marshmallow requires a faster valve to achieve this objective than a steel ball.
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Unread postAuthor: velocity3x » Mon Jul 05, 2010 11:49 pm

Technician1002 wrote:There is a point of diminishing returns where fast is fast enough.


I guess we'll just have to agree to disagree on that. :lol:
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Unread postAuthor: Technician1002 » Mon Jul 05, 2010 11:55 pm

GGDT models it well. There is a trade off between strength, weight, and speed. Pick your performance. The Mouse Musket was built for extreme valve speed due to the short length. That resulted in many broken pistons. The replacement piston is quite a bit heavier, but much less brittle.
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Unread postAuthor: jackssmirkingrevenge » Tue Jul 06, 2010 12:11 am

velocity3x wrote:I guess we'll just have to agree to disagree on that. :lol:


Seriously though, in the quest for the ultimate performance, have you considered the "valveless" idea?

There is no other system that will give you 100% flow with zero "opening time", and if you're using solid projectiles with the benefit of proper machining facilities it should be a doddle to put together.
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Unread postAuthor: Technician1002 » Tue Jul 06, 2010 12:20 am

I have considered it. I looked at the work to make a single piston and without a lathe, I decided to simply have a dual valveless design. The piston shoots to the rear and is safely caught and is re-used. The other projectile can be of another size becasue of removable barrels. I decided against the valveless design due to the limited size (one per chamber barrel combination) and the loss of the projectiles. I have never found a golf ball launched for distance. I still don't know how far I shoot them. The QDV is a close second to a valveless launcher. Being able to launch projectiels such as rolls of adding machine tape, full soda cans (and empties), tennis balls, golf balls etc is the primary reason to sitck with the QDV instead of a valveless. The performance gain is minimal, but the restriction to the projectile is too much to give up.

I have accidently launched the piston out of the ABS cannon once as I was positoning the piston to try to reduce a leak. It got a little forward and it launched. :shock: This was before I had the golf ball on the rope, so it launched rope and all. I found the piston becaue I found the rope spread on the brush it landed in. Thank goodness it was a relatively low pressure shot.

I guess you can say I have made a valveless launcher and converted it into a QDV.
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Unread postAuthor: velocity3x » Tue Jul 06, 2010 1:58 am

jackssmirkingrevenge wrote:Seriously though, in the quest for the ultimate performance, have you considered the "valveless" idea?


JSR,
I hadn't considered the idea but, after looking at the link / drawing you provided, I must say that I find it to be a somewhat intriguing concept.
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Unread postAuthor: jackssmirkingrevenge » Tue Jul 06, 2010 3:01 am

velocity3x wrote:I hadn't considered the idea but, after looking at the link / drawing you provided, I must say that I find it to be a somewhat intriguing concept.


Not a new idea and it does limit the type of projectile one can use and demands an airtight breech, but you clearly have the facilities to get around these issues. Here's some work I had done on the subject.
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Unread postAuthor: Technician1002 » Wed Jul 14, 2010 2:14 am

jhalek90 wrote:
Tech... i would assume a high velocity pop can would make easy work of a 1'' limb...... well, after work today i will be sure to get photos of the branch as well as a video of the cannon.


I didn't measure the size of the diameter but we did take a limb out of a 60 foot tall pine tree near the top with a can of pop last year. I lost touch with the guy that shot the video at the retreat, so have been unable to get a copy. :( . It was impressive, the can went right into the top of the tree and clipped off a branch a little over 6 feet long right at the trunk. It fell to the ground so we know the length. We retrieved some small parts of the can we found, but most of the can parts stuck in the top of the tree.

I think the limb a little over 6 feet in length was a little larger than 1 inch, but it was not measured.

Nothing will come close to the superior performance of a powered ball valve.


Personally I have my doubts. I would like to do some side by side testing to find out. I don't think a ball valve is as quick as a QDV and I think the QDV has an edge on flow capacity. The ID of the valve is the ID of the pipe it is in, not slightly smaller as some ball vavles are.

The QDV also has no plumbing for pressure loss between the chamber and valve.

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Unread postAuthor: velocity3x » Wed Jul 14, 2010 8:26 pm

1.25" ball bearing vs. car + 6 sheets of 3/4" ply wood + sand bags.
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Last edited by velocity3x on Fri Jul 16, 2010 10:35 pm, edited 1 time in total.
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Unread postAuthor: jackssmirkingrevenge » Thu Jul 15, 2010 12:22 am

Hell's bells and buckets of blood! Is this from the ultimate damage video which we never got to see :?
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