Page 1 of 1

hammer valves versus...

Posted: Mon Mar 28, 2016 3:19 pm
by Anatine Duo
So I just finished playing with my quick and dirty Po' Boy Sixty-Fo' with a commercially available qev and got to thinking...

What is the advantage of using air opened valves rather than a hammer valve in smaller calibers (up to 1" for example)

My first valve back in 2001 was a hammer valve because I had been researching traditional big bore airguns. I had been told by a spud enthusiast that it would be too hard to open, which turned out to be false. It had cross sectional area greater than the barrel so it had lots of flow. It had a mechanical trigger which I like. After the Po' Boy my next project was going to be a hammer valve piloted qev but I started questioning that idea to revisit the hammer valve as powerplant.

Possible advantages are that a very small hammer can be used to pilot a qev, so less bouncing around during firing cycle than a big hammer directly on a big poppet, maybe advantageous for accuracy especially on lightweight launchers.

Seems pretty obvious on the spud size launchers that the pneumatically opened valve will be easier to operate than a giant poppet, but what are your thoughts on smaller calibers?

Re: hammer valves versus...

Posted: Mon Mar 28, 2016 4:02 pm
by keks2033
Anatine Duo wrote:So I just finished playing with my quick and dirty Po' Boy Sixty-Fo' with a commercially available qev and got to thinking...

What is the advantage of using air opened valves rather than a hammer valve in smaller calibers (up to 1" for example)

My first valve back in 2001 was a hammer valve because I had been researching traditional big bore airguns. I had been told by a spud enthusiast that it would be too hard to open, which turned out to be false. It had cross sectional area greater than the barrel so it had lots of flow. It had a mechanical trigger which I like. After the Po' Boy my next project was going to be a hammer valve piloted qev but I started questioning that idea to revisit the hammer valve as powerplant.

Possible advantages are that a very small hammer can be used to pilot a qev, so less bouncing around during firing cycle than a big hammer directly on a big poppet, maybe advantageous for accuracy especially on lightweight launchers.

Seems pretty obvious on the spud size launchers that the pneumatically opened valve will be easier to operate than a giant poppet, but what are your thoughts on smaller calibers?
I am using the hammer with a QEV valve for a long time.[youtube][/youtube]On my channel there are still examples of the impactor

Re: hammer valves versus...

Posted: Tue Mar 29, 2016 9:41 pm
by jackssmirkingrevenge
Hammer valves are not an obvious choice for home made spudguns because it's much easier to pilot an exhaust valve (simply opening a small valve to exhaust a chamber) for massive and quick flow than to have to build the mechanism to open such a valve that will resist the impact, especially on a large scale. If you have the proper materials and resources though, they are an excellent choice especially for repeaters where only a momentary blast of air is needed.

The disadvantage of typical hammer valves is that the bigger they get and the higher the pressure, the more force is need to open them. There are ways around this though, have a look at BtB's Counter Balanced Hammer Valve.

Certainly on commercial airguns the hammer valve is virtually universal, the question is what are you building - a powerful single shot gun, or are you looking to get multiple shots from a single chamber?

Re: hammer valves versus...

Posted: Sun Apr 03, 2016 2:26 am
by Hurricane Air Arms
Personally I was never a fan of QEV's because of the fact that they dump HPA that could otherwise be used.

Hammer valves are commercially favoured because of their precision.

However, using a hammer valve to actuate a QEV exhaust? Never heard* of such a thing. As the above post states, it's what you need/want it for.

I would imagine that a hammer-actuated QEV would give you maximum precision and consistency with the ability to tune the hammer spring. It's a handy idea, but it would be potentially messy to build.

Re: hammer valves versus...

Posted: Fri Apr 15, 2016 11:02 am
by Brian the brain
depends on what you call messy


Below two multishot launchers I made..

Hammervalve piloted coaxial pistonvalve:
Image

Hammervalve piloted QEV:

Image

Re: hammer valves versus...

Posted: Sat Apr 16, 2016 7:32 am
by Anatine Duo
IMG_20160403_121329.jpg
Thanks for your thoughts. Above is my first valve of any kind. The second was similar and installed in my first launcher. Surprisingly easy to open, and gave a second shot. Iirc (14 years ago) it recocked too.

Brian it may have been your set up that inspired me to look into this, but then I keep seeing high power hammer valves in factory pneumatics so I am trying to clarify why we build a hammer valve to pilot a qev, other than it seems elegant

I think jsr summed it up well. I am not sure how long my hammer valve would last either before breaking or losing too much pressure... But that seems to be problem with lots of homebuilt valves

Re: hammer valves versus...

Posted: Tue Apr 19, 2016 1:04 pm
by Brian the brain
I keep seeing high power hammer valves in factory pneumatics so I am trying to clarify why we build a hammer valve to pilot a qev, other than it seems elegant
Flow. With a hammervalve piloted QEV you'll be able to get full flow in , say, a 3/4" inch barrel, at high pressure.
Depending on the size QEV you use offcourse. Now try that with a commercial hammervalve.

It's like comparing a moped to a top fuel dragster....