SpudFiles

THUNDERLORD wrote:Double (but new info/ques.):
I really like this design,:

But I think it could be simplified (Greatly)

I have a question. Something I don't understand is how the pulse chamber continues to fill after the valve starts to move. If the initial pressure isn't high enough, and a cycle doesn't reach the ball launch position, I can see this as getting stuck with the piston just off the rear fill valve. Am I missing something?

**Edit**
Nevermind I think I figured it out. The main piston is a pop off valve with a small seat. I missed that. Maybe a slight change to the drawing to show a thin valve seat gasket would help.

**Brainstorm edit
I do like the design.

Maybe the valve ball and rod can be replaced with a caped pipe or tube. In the initial position, air would go into a port in the pipe to the chamber. As the valve pops off, the fill port remains open for part of the travel until the port goes through the back wall o ring gasket.

This design change with the longer rod won't suffer the possibility of the present rod from getting vibrations and missing the fill valve hole.

After launch, the chamber would get a head start refilling. It would make the rod lighter being hollow and possibly increase the fire rate. Maybe the o ring would add too much friction. I should stop typing while brainstorming.

Just an idea. I do like the design.

From my experience since I drew up that design I've preferred to go down the route of having a separate valve with constant flow and breech mechanism, however the above design should function if made correctly.

Thunderlord, those barrel liners look like a really good find! Dirt cheap and on their own probably strong enough to operate at spudgun pressures.

Jack; this is what I pmed you about.

Better?

Essentially isn't it just a slightly reconfigured variation of this?

Not really. This ports immediately to the barrel, allowing for full power. Air is then diverted to a check valve which operates a separate blowback mechanism.

Without the check valve air would flow all out of the barrel and not actuate the blowback mechanism.

So basically:
You lose power
OR
You lose full auto

This keeps full auto and full power by not using exhaust from the blowback to power the gun. That said, it's less efficient again as you're running a 2 cycle engine that's doing near nothing except strike a valve.

You could use the exhaust air for something to do with a hopper like someone suggested.

inonickname wrote:Not really. This ports immediately to the barrel, allowing for full power. Air is then diverted to a check valve which operates a separate blowback mechanism.

In my design above the blowback operation is ensured by making the air push the hammer back before being able to exit to the barrel.

Air will simultaneously go both into the barrel and blowback mechanism, and once the projectile has left the barrel all the air will go through there as it is the path of least resistance. In this case the check valve is a good idea, because the air then won't have the option of exiting the barrel.

Looking like it could be made to work, give it a go

...Thunderlord, those barrel liners look like a really good find! Dirt cheap and on their own probably strong enough to operate at spudgun pressures.

I was thinking after I linked to those that IIRC .22 pellets are around .221 while .22 cal. firearms are .223(+?).
So that may be a better barrel than an airgun barrel since .223 (whatever type) could be used, or .22 bb's or pellets.

My thoughts on changes to that design were only slight changes.
The pipe rather than blocker tube still might need vent holes near the valve and washers or piston on the barrel (in front of blocker tube rather than pin) to counter the spring tension better.
I was daydreaming of components to build it out of and the simplicity sort of amazed.
I think the advantages to that design would be the number of shots and effeciency for shorter barrels and smaller diameter shot.

BTW, a long time ago I had a daisy(?) CO2 pistol that functioned similarly.
Except it had a lever underneath a plastic wood piece below the barrel.
It had to be cocked forward before each shot ,Which pulled the barrel forward and loaded a BB.
Trigger pull released the barrel which had a flat pointed metal piece across the center (back).
If you pressed the trigger and released the lever (with thumb) instead, It slammed the barrel into the valve and a much larger blast co2 came out!
It blew the loader sleeve onto the barrel (doing that), so I took it apart to fix it. It had a short smooth bore and wasn't very accurate though.
Glad you saw my reply JSR! 8)

EDIT: Just looked at the diagram again and the only chages I mentioned really are external spring (from bolt) and barrel movement (rather than seperate loader tube) Dang, I could have typed so much less! 8)
EDIT2:

jackssmirkingrevenge wrote:From my experience since I drew up that design I've preferred to go down the route of having a separate valve with constant flow and breech mechanism,...

Same design except the valve would be the pilot maybe??? 8)

jackssmirkingrevenge wrote:

inonickname wrote:Not really. This ports immediately to the barrel, allowing for full power. Air is then diverted to a check valve which operates a separate blowback mechanism.

In my design above the blowback operation is ensured by making the air push the hammer back before being able to exit to the barrel.

Air will simultaneously go both into the barrel and blowback mechanism, and once the projectile has left the barrel all the air will go through there as it is the path of least resistance. In this case the check valve is a good idea, because the air then won't have the option of exiting the barrel.

Looking like it could be made to work, give it a go

Yeh.

The reason this design would be more powerful than yours is because it expands several times before even hitting the barrel (so your basically just using an exhaust), mine uses a charge that goes straight to the barrel and one to the hammer. Less efficiency, moar power.

Back on that design I quoted in reply,
Most co2 pistols use valves that work similarly(as far as duration of co2 blast). And with heavier spring tension a lot of co2 pistols give a larger blast.
Only problem I forsee is with larger bores, the trigger will need to be designed well for a reasonable trigger pull to release the barrel (my change) or loader tube (same).
I am thinking of a brass reducer bushing (probably about 1/8- 3/8) ,
Drill out the 1/8" (actually about 3/8" OD) and tap(thread) the hole for 88gram threads.
That would thread into a (perhaps) 3/8" (brass 3/8" nipples are actually 1/2"ID) Thickwall brass coupling.
Cut a short piece of threaded pipe threads and add a few tightly fitting washers and epoxy to sandwich the washers (inside coupling).
Add spring (behind ball bearing), rubber/plastic washer and ball bearing that fits like diagram.
Thread front pipe (barrel sleeve)into coupling to sandwich washers (front) It's over half way finished.
Needs pin to puncture cartridge, blocker tube (with vent holes near valve(?)
For barrel work: washers or piston on barrel (in front of blocker tube) to assist spring tension(?) , bolt or welded pin in breech (that will strike valve) and holes in barrel sides. And washer on other end to retain spring
Of course the hardest part would be fitting the trigger and magazine adjustment.
I am tempted to put my other high pressure JSR type BFB on hold to build a .22, .25 or even .375 version!!!

On the barrel liners I linked to, they sure look like lamp pipe externally but are much different. (Lamp pipe for wiring lamps has matching threads, same OD as "1/8" brass pipe" but .27ID and are seamed BTW 3/8" OD lamp pipe fits seamed 1/2" round stock in hardware, can be fitted in 3/8" brass or 1/2" galvanized. 1/4" ID brass tubing fits ID lamppipe).
Also...Hmmm... Seems like someone could replace the lamp pipe inside some lamps with those (threaded ends even?), ...overseas on ebay.
I wonder if rifled lamp pipe is even prohibitted(?). Also how would the buyer have known his used lamp had it inside. 8)

EDIT: Can't figure WTF is a "Cool" where I typed "1/8-3/8" reducer bushing, and cant get rid of it!

Sort of Double, But I was thinking of a hammer valve similar,
except with a shrader at each end for fueling a hybrid chamber.

How it could work is the trigger latch would release the hammer to strike the fuel shrader, it would bounce releasing the fuel through a port hole into chamber,
And then strike the higher pressure air/oxidizer shrader on the other end, releasing that through a port hole into the chamber.
(The port hole would have one way valves)

Perhaps the combined pressure (of fuel and oxydiser) would move something inside the chamber to the point where it contacts a switch initiating spark.

It would probably take a lot of fiddling to get the right mix though. 8)

THUNDERLORD wrote:It would probably take a lot of fiddling to get the right mix though. 8)

Not to mention the risk of the hammer sparking and igniting the mix