DEAD 43mm (GB) Semi-Auto Video 2!

jackssmirkingrevenge · Sat Apr 24, 2010 3:02 pm

Lovely! Especially towards the end. You know, you're a timer circuit away from having a golf ball autocannon... not to put any ideas into your head or anything

c11man · Sat Apr 24, 2010 3:15 pm

You know, you're a timer circuit away from having a golf ball autocannon... not to put any ideas into your head or anything

do you really think this hasnt crossed my mind? i am looking into it and if i do make a circut i will add things such as a digital pressure sensor that i have laying around( i have lots of goodies laying around dont it?) so that it wont attempt to fire if the chamber is under 50psi so that the valves properly accuate

Mr.Sandman · Sat Apr 24, 2010 4:02 pm

c11man wrote:
You know, you're a timer circuit away from having a golf ball autocannon... not to put any ideas into your head or anything
do you really think this hasnt crossed my mind? i am looking into it and if i do make a circut i will add things such as a digital pressure sensor that i have laying around( i have lots of goodies laying around dont it?) so that it wont attempt to fire if the chamber is under 50psi so that the valves properly accuate

Am I sensing a tone of hostility? Hehe. Looks good c11 The valves add a nice touch.

deathbyDWV · Sat Apr 24, 2010 6:05 pm

Looks really good. I must have missed this when you first posted it... Maybe drilling a hole in the back of the bolt is all I needed to do to make mine work...

Video is good too...

jackssmirkingrevenge · Sun Apr 25, 2010 4:31 am

c11man wrote:do you really think this hasnt crossed my mind? i am looking into it and if i do make a circut i will add things such as a digital pressure sensor that i have laying around( i have lots of goodies laying around dont it?) so that it wont attempt to fire if the chamber is under 50psi so that the valves properly accuate

Looking forward to it

You might consider adding a bypass with a check valve to fill the chamber quicker.

c11man · Sun Apr 25, 2010 3:36 pm

i am planning on reduing the piston with some highflow check valves built in for faster filling, a bypass is also a good idea but if the cracking pressure is too low the piston might have trouble seating

with the parts i have ordered i will be able to adjust the ROF from 25rpm al the way up to 70rpm. even with the new piston and a good compressor i dont see this cannon being able to handle over the 70rpm so i think i am good

c11man · Sun Apr 25, 2010 10:34 pm

due to the repeated slaming forward of the piston against the porting pipe it developed a crack and the pressure blew a chunk of that pipe out. of course the piston has a bit of trouble sealing on a pipe thats not all there.
so in other words this cannon is currently DEAD/BROKEN!
it will be fixed but that will take some time due to the fact that the entire valve section will need to be replaced since it is all glued together

suggestions for improvements/upgrades that i can do while fixing it?

Mr.Sandman · Sun Apr 25, 2010 11:07 pm

c11man wrote:due to the repeated slaming forward of the piston against the porting pipe it developed a crack and the pressure blew a chunk of that pipe out. of course the piston has a bit of trouble sealing on a pipe thats not all there.
so in other words this cannon is currently DEAD/BROKEN!
it will be fixed but that will take some time due to the fact that the entire valve section will need to be replaced since it is all glued together

suggestions for improvements/upgrades that i can do while fixing it?

I had a very strong feeling this was going to happen. A new part if you rebuild it should be a bumper. You have a knack for breaking pvc pipe with your creations eh?

c11man · Sun Apr 25, 2010 11:15 pm

there is a bumper behind the piston but thats not what broke, after firing the piston is back, valve is opened and the piston slams forward. this repetative slamming caused the smaller 1 1/2in pipe to break.

and i dont have a knack for it, they are just accidents. only twice has my pcv broke and once was dwv

Mr.Sandman · Sun Apr 25, 2010 11:29 pm

c11man wrote:there is a bumper behind the piston but thats not what broke, after firing the piston is back, valve is opened and the piston slams forward. this repetative slamming caused the smaller 1 1/2in pipe to break.

and i dont have a knack for it, they are just accidents. only twice has my pcv broke and once was dwv

Sigh I can never have a joke can I

No what I meant was a bumper on the bolt or maybe a stronger barrel and bolt made of metal. Pvc doesn't like being subjected to high impact for some reason.

Gun Freak · Mon Apr 26, 2010 4:01 pm

Oh dang that sucks, I know what its like to rebuild whole glued sections

Gaderelguitarist · Mon Apr 26, 2010 7:11 pm

Perhaps you could use a softer type of rubber for the sealing face of the piston. That might work.

30cal man · Mon Apr 26, 2010 8:50 pm

here is a quick drawing i drew up for a very simple full auto circut it works i tried it when i used something simular to make a c cell batterie launcher however i lost interest when i ran out of c batteries which was very quick let me know what you think

Uploaded with ImageShack.us

POLAND_SPUD · Mon Apr 26, 2010 9:08 pm

not a bad idea but it will be easier to use a timer relay

c11man · Mon Apr 26, 2010 9:45 pm

yeah im not gonna mess with screws and contacts on the bolt. but a very creative idea!

what i am going to do is place a spring behind the piston so that it is against the barrel before pressurization elimitateing the forward slam of the piston. also i will put a bypass hose from the pilot area to the chamber that will hasten filling and a check valve will prevent back flow.

so i gotta order some parts, go to the store and it should all be up and running in about 3 weeks

DEAD 43mm (GB) Semi-Auto Video 2!

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