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Posted: Tue Sep 13, 2011 7:54 pm
by Atattack
.07 seconds? It is a dust collector valve which is supposed to be one of the fastest valves. Double diaphragm port valve. Isn't that pretty fast?

Posted: Tue Sep 13, 2011 8:05 pm
by Fnord
Yeah, your valve has a fairly low-mass diaphragm with a decent "step-up" ratio when it cracks open (meaning, when it opens, the air pressure will suddenly have more sealing face area to push on and thus open faster).

I'd figure it's probably close to 10 ms if the pilot valve works well.

Posted: Tue Sep 13, 2011 8:09 pm
by Atattack
I talked to one of their engineers today and he said it opened between 50-70 ms. I hope it opens in 10 ms.

Anyone know a way to make a muzzle brake like device without make the gun any louder? Is there a way to have a suppressor help with recoil?

Posted: Tue Sep 13, 2011 8:23 pm
by Fnord
If he can actually cite lab test results then I'd tend to believe him, but with only GGDT to pull numbers from I can't get this valve to open much slower than 40 ms... still quite a difference and that was calculated with horrible pilot params.


I don't think you can make a quiet muzzle brake. They work by directing energy back toward/perpendicular to the shooter, which always results in more noise in those directions.

A suppressor may help a bit, though (only guessing here) the additional weight would probably be more of a factor than anything. How do you plan on silencing something so huge?

Posted: Tue Sep 13, 2011 8:37 pm
by jhalek90
[youtube][/youtube]

This is a 1.9'' porting cannon... that video shows no barrel, and no projectile, at 100 psi.

The cannon weight in at 65lbs. with a barrel, and i refuse to shoulder mount it at anything above 35psi.

I fired it once at 150psi with a 1lb projectile while i had it on a sling over my shoulder..... i fell flat on my ass.

At 250 psi, i set the cannon on the ground, and lean all me weight into it (i weigh 165lbs) and still sometimes get tossed around.

Posted: Tue Sep 13, 2011 8:41 pm
by mattyzip77
I have a 1 1/2 inch one and it is more powerful than my piston valve with 1 1/2 inch porting. I would say get it!! Check out E Bay, I just got another 1 1/2 inch one last week for 45 dollars shipped!!! I seriously dont think I will ever make another piston valve again after using these!They truly are powerful, easy to use, basically plug and play, and just down right awesome!!! :D :D

Posted: Tue Sep 13, 2011 9:19 pm
by Atattack
I am still undecided on which to get, the last post jhalek is what I am worried about. I want a gun I can fire from shoulder without getting hurt.

Posted: Tue Sep 13, 2011 9:28 pm
by Technician1002
Atattack wrote:.07 seconds? It is a dust collector valve which is supposed to be one of the fastest valves. Double diaphragm port valve. Isn't that pretty fast?
This depends on the parameter being measured. If this is a delay (which I think it is) there is a delay while the pilot and nominal pilot plumbing is vented before the valve unseats, then it pops open.

Most piston valves and membrane valves need the pilot to drop to a low pressure, then they pop open. You can see that in the sound recordings of many piston valve cannons. It is hiss-boom..

Image

Posted: Tue Sep 13, 2011 9:29 pm
by Fnord
If you can get a 2" valve cheaper there's no reason not to get it unless valve size is a concern.

As Tech already suggested, if you want less power, use less pressure. A more efficient valve is a no-brainer.

Also, I think jhalek's problem may have been more to do with the center-of-mass shift that occurs from 65 pounds suddenly throwing you off balance, rather than the perceived "impact" of the recoil. I imagine it would be more like being tackled by a midget than kicked by a mule.

Posted: Tue Sep 13, 2011 9:32 pm
by Atattack
Haha, well my gun will weigh around 30 pounds I am guessing. Already have some fittings and about to order rest once I decide on size. Will be aluminum so won't be an extremely heavy fun.

Well, won't I be able to compensate for the lack of efficiency b using a higher pressure? The 2" valve is double the cost of 1.5" valve.

Posted: Tue Sep 13, 2011 9:34 pm
by Fnord
Oh, whoops, I misread one of your previous post. I thought the 2" valve was cheap than the 1.5", for some reason.

Edit, have you checked Ebay?
http://www.ebay.com/itm/Kice-auto-pulse ... 3365a1fd4c

http://www.ebay.com/itm/ASCO-DIAPHRAGM- ... 2eb7d50a0c

http://www.ebay.com/itm/GOYEN-CONTROLS- ... 45f6cbc6b2

http://www.ebay.com/itm/GOYEN-RCA45T000 ... 35adc363c6

some of these are surplus. There are more out there but I only looked briefly.

Posted: Tue Sep 13, 2011 9:36 pm
by Atattack
All good man, I just don't want to buy this really powerful valve and I can't use it to full potential cause it's too powerful.

Posted: Tue Sep 13, 2011 10:40 pm
by Technician1002
Go ahead and get the big valve. Not all the fun is limited to heavier projectiles. Launching empty pop cans and sabotted AA batteries, tennis balls and such are relatively low recoil events. Recoil is an issue with larger barrels, higher pressure, and heavier projectiles. You will want the power for smaller lighter projectiles. Don't limit yourself.

Image

Posted: Tue Sep 13, 2011 10:43 pm
by Atattack
This is probably a dumb ? bur I want to make sure before buying the valve.

If I have to fire the 2" valve at lower pressure do to recoil than say the 1.5" valve. The heavier projectile even though firing at a lower pressure will still go a further distance than say the 1.5" at a high psi correct.

Posted: Tue Sep 13, 2011 10:49 pm
by Technician1002
Model it in GGDT.. When launching eggs, I found they can fly the distance from an industrial park building over a car dealership lot and drop on the roof. A small higher pressure valve would have most likely broken the egg on launch. I wonder if the dealership heard it land on the roof. :roll: