GB Semi

[mate68]

nice one!, how ever im planning to shoot tennis balls, i have it almost redy so far ill uplode some pictures soon, havent been able to spend much time in the forums due to some hard test

[Gepard]

Thank you for telling us your life story (and kicking up a dead topic at the same time).....now can I please have my the past 2 minutes of my life back?

[Spudnik Tweaker]

I too am in the process of designing a new type of valve. Just went through this thread and now have quick questions for Clide or anyone else whom understood his design.

In Clide's diagram, I could not understand what the purpose of the bent piston rod and chamber bore was for. ....Anyone care to explain?

Also, Clide, how did you actually create those bends? I remember that you used heat process for something -- was it for the very purpose of creating the bends? (just curious)

Thanks all.

[Marco321]

I too am in the process of designing a new type of valve. Just went through this thread and now have quick questions for Clide or anyone else whom understood his design.

In Clide's diagram, I could not understand what the purpose of the bent piston rod and chamber bore was for. ....Anyone care to explain?

Also, Clide, how did you actually create those bends? I remember that you used heat process for something -- was it for the very purpose of creating the bends? (just curious)

Thanks all.

Those are diagram notation, not part of the actual picture, they indicate an amount of the chamber. Instead of using like 2 pages to make the chamber of the diagram, those bends are used in a drawing to indicate the length is longer than the diagrom shows, they represent a part of the chamber has been removed to make it small enough to practically show the demonstration of the valve.

I believe he heat bent the handle

[Spudnik Tweaker]

Those are diagram notation, not part of the actual picture, they indicate an amount of the chamber. Instead of using like 2 pages to make the chamber of the diagram, those bends are used in a drawing to indicate the length is longer than the diagrom shows, they represent a part of the chamber has been removed to make it small enough to practically show the demonstration of the valve.

I believe he heat bent the handle

Aha! I thought that those bends were actually part of the design and played a role in the pressure tuning -- I tend to overthink and over complicate things, making things out to be more difficult than they actually are.

Thanks for the thorough explaination. ...Good to know that people pay attention and help out others in need.

[Marco321]

Those are diagram notation, not part of the actual picture, they indicate an amount of the chamber. Instead of using like 2 pages to make the chamber of the diagram, those bends are used in a drawing to indicate the length is longer than the diagrom shows, they represent a part of the chamber has been removed to make it small enough to practically show the demonstration of the valve.

I believe he heat bent the handle

Aha! I thought that those bends were actually part of the design and played a role in the pressure tuning -- I tend to overthink and over complicate things, making things out to be more difficult than they actually are.

Thanks for the thorough explaination. ...Good to know that people pay attention and help out others in need.

Lol, it happens to the best of us

I'm always glad to help where i can

[BOMBOMBOMB]

DUDE thats some crazy shizit beautiful. HAHA make it a bit mroe powerfull and tweak with the consistency of ammo flow. Apart from that awsome. Nice rebound in first vid. Second video yoru dad looked pissed
Cheers Nato

[tsb]

Love it, Love it.
@ BOMBOMBOMB
I agree, it needs to be more powerful.

It's still great, good work.

Cheers,
tsb

[gwoloshyn]

GREAT cannon. Your really smart and I look up to ya. Wish I had the time to put together a cannon like that :/

[jack_the_hack]

i see things have advanced alot since i left





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Just keep it simple...

[ninjafroglet]

I'd be keen to see a set of plans for this

[jackssmirkingrevenge]

I'd be keen to see a set of plans for this

No offense but if you can't get all the information you need from the diagram then you're probably not qualified in terms of experience and know-how to succesfully replicate the design.

[Copperboy]

Really beautiful cannon, great work!

I have a question though, you say:

"The rear part of the valve is slightly larger then the front."

About how much difference in surface area is there?

[Thunderbug]

Sorry to kick open an old topic, but I actually have something new for you, Clide.

First, I'd like to congratulate you for coming up with this er... contraption.
Did you think the HEAR valve up yourself? (Yes or no will do, I didn't search for it, so flame me at my peril )
It was just what I was looking for, anyway.
Have you worked out the bugs yet?
If not, I have a few suggestions for you.

First, your problem in full auto/rapid semi seems to be timing.
It looks/sounds like your HEAR valve is chugging along happily ignorant of your blow-forward-bolt-loader (BFBL).
That would be alleviated by a mechanism preventing the HEAR valve from cycling unless the BFBL was in battery (back position).
My first suggestion would be some mechanical link (push rod or trip lever) opening a full auto sear on the HEAR valve (yes, a second sear).
Push rod from the BFBL chamber or trip lever operated by the front of the loading bolt (or probe).
That way, you keep the trigger in (give clearance for auto fire), but the loading mechanism tells the air dispenser when to fire.

Second, I have this notion you'd be better off exchanging the rubber sleeve stopper thingy in the BFLB with a heavy-ish spring.
That's assuming your HEAR valve operates faster than the BFLB, of course.

Third, eheheh...
Someone noticed your erm... Multi-shot capability.
Capping the mag is an easy way out, but maybe an O-ring seated in the "receiver" between the BFLB spring and the loading port?

I hope to be able to shamelessly copy your design someday, as I'm researching the possibility of constructing a full-auto-capable pellet firing pre-charged air rifle someday... Someday...

Claude Lacombe in Close Encounters: I envy you!

[clide]

Hi, welcome to the forums Thunderbug

Yes the HEAR valve design was basically my own. Of course I got some inspiration from the various valve designs I've seen over the years, but I don't recall seeing anything that had the same features present in this valve.

I haven't got around to working out the bugs yet, but I have been thinking about getting it out and doing some work on it. Really I think the actual valve is working great with the current design. It's the blow forward breech that is giving me fits.

Once I added the weight to the bolt it slowed it down to the ~8 cycles per second which the bolt should easily be able to keep up with when it is operating properly.

I have considered linkages from the piston to the bolt. In fact initially I was strongly considering powering a bolt directly from the movement of the piston. Eventually I decided against any linkages with one of the main reasons being that it would just be to complex and hard to assemble. As it is now it is still quite time consuming to take it apart and reassemble the parts because of how it has to be assembled to remain compact. I'm not really up to doing it because I foresee it just being way too frustrating, but I think it is a valid idea and would certainly be worth considering if you are building your own.

I haven't confirmed it, but from my experimentation I think that my biggest problem with the bolt is getting it to seal. I believe what is happening is that air is escaping around the bolt and up into the loading port which blows the ammo up the tube a little, that little bit is enough to make it not feed fast enough. Really I need to remake the bolt and even possibly the whole breech and pay closer attention to the seals.

Currently the seals are two o-rings on the bolt, but as you mention it may be better to put the rear o-ring in the breach assembly rather than on the bolt, but that would require a complete rebuild of everything downstream of the valve which is probably the best solution.

I've started work on a how-to for designing a HEAR valve launcher. Doing so made me realize that I would have dimensioned my launcher differently if I had thought more about all the variables before hand. Hopefully it won't be too long for me to complete the guide because I've forbidden myself from posting my more recent creations until I post the guide.

Copperboy: I don't know if your still around, but I must have missed your post. I don't remember exactly, but I believe it is something like a tenth of an inch bigger in diameter. I believe I sized it to produce about 20 lbs of force at 100 psi.