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Posted: Fri Apr 17, 2009 6:52 pm
by SubsonicSpud
jackssmirkingrevenge wrote:
psycix wrote:Cant wait to see it! Dont dare to fail now! :wink:
Too late :(

Image

No pop-pop-pop, just a fish with no eyes.

Dammit.

Similar thing happened with my attempt at a pop-off piloted piston with a very small chamber - maybe it does need an expansion chamber after all, hmmm...
Thats a bummer :(

Is the new design seviceable? If so some trial an error with port and valve seat areas may be in order, might get it to work yet :?

SubsonicSpud

Posted: Fri Apr 17, 2009 7:20 pm
by jackssmirkingrevenge
SubsonicSpud wrote:If so some trial an error with port and valve seat areas may be in order, might get it to work yet :?
I'm quite happy with those parameters, I'm convinced it's the lack of chamber between the tank valve and pop-off that's not making enough energy available for the valve to actually pop. I've grafted a chamber to the valve, I'll see how it sets as soon as everything's cured. Not giving up on this one ;)

Posted: Fri Apr 17, 2009 7:37 pm
by SubsonicSpud
jackssmirkingrevenge wrote:
SubsonicSpud wrote:If so some trial an error with port and valve seat areas may be in order, might get it to work yet :?
I'm quite happy with those parameters, I'm convinced it's the lack of chamber between the tank valve and pop-off that's not making enough energy available for the valve to actually pop. I've grafted a chamber to the valve, I'll see how it sets as soon as everything's cured. Not giving up on this one ;)
Ok I see what you mean now, hopefully that works

Posted: Fri Apr 17, 2009 10:41 pm
by littlebro05
Hmm, now I want to make one... making this seems more easier than making a vortex BBMG. I love your damage XD.

I guess I'll work on both, see which one is more efficient and powerful (but I assume your one is way efficient if you get the volume ratio vs spring right).

Posted: Fri Apr 17, 2009 11:07 pm
by jackssmirkingrevenge
littlebro05 wrote:Hmm, now I want to make one... making this seems more easier than making a vortex BBMG. I love your damage XD.
The design of the valve is so simple it's not that hard, the complexity comes from having to make a feed system too.
I guess I'll work on both, see which one is more efficient and powerful (but I assume your one is way efficient if you get the volume ratio vs spring right)
.

This will always be more efficient than a vortex, it will shoot less shots per minute but each shot is more powerful.

In the meantime, here's what version 3 looks like. Ignore the awkward angles and dimensions, this is just a prototype to determine performance. In practice I could make it a lot more compact, and it would have to include a ball valve of some description to be included in a trigger mechanism. Originally it was just the grey valve portion but I've now added a section of stainless tubing as a chamber, to be tested later today :)

Posted: Sat Apr 18, 2009 12:46 am
by littlebro05
Haha, Now you've just convinced me to make you're design now XD... I think I'll work on a bolt system built into... I think it'll be easy... I hope LOL...

I'm just going to follow your full-auto system with your semi-automatic breech system in one... I think that should work...

Posted: Sat Apr 18, 2009 4:24 am
by SubsonicSpud
littlebro05 wrote:Haha, Now you've just convinced me to make you're design now XD... I think I'll work on a bolt system built into... I think it'll be easy... I hope LOL...

I'm just going to follow your full-auto system with your semi-automatic breech system in one... I think that should work...
The problem with using a blow forward or blowback breach at this sort of scale is it reduces the system performance significantly. If you do make one, keep the valve system and reloading system as seperate components, it will enable you to perfect or replace the reloader without affecting the valve.

Posted: Sat Apr 18, 2009 5:28 am
by littlebro05
SubsonicSpud wrote:
littlebro05 wrote:Haha, Now you've just convinced me to make you're design now XD... I think I'll work on a bolt system built into... I think it'll be easy... I hope LOL...

I'm just going to follow your full-auto system with your semi-automatic breech system in one... I think that should work...
The problem with using a blow forward or blowback breach at this sort of scale is it reduces the system performance significantly. If you do make one, keep the valve system and reloading system as seperate components, it will enable you to perfect or replace the reloader without affecting the valve.
Sorry if I seem like I'm hijacking the thread but, I was going to use the same concept just with different placement so yeah... but I'm just working on the small amount of machinery I have... i.e. hand held battery drill and hacksaw... it's pretty much all I have lol. Well I guess we'll find out soon.

Thanks for the idea JSR XD. I now can work with different variations.

Posted: Sat Apr 18, 2009 6:51 am
by jackssmirkingrevenge
I tested the HP valve with chamber added and still no popping, and I think I've figured it out. The fitting I used at the piston seat has a 3mm restriction, when the outlet is 4mm, so it's not going to work.

I've made a new one, 8mm seat, 6mm outlet to give maximum flow for 6mm barrels and below and a piston with an area just over 3 times that of the seat so it should pop quite healthily, results in 24 hours ;)

Posted: Sat Apr 18, 2009 7:07 am
by SubsonicSpud
Good to see the problem is found (hopefully) :D
jackssmirkingrevenge wrote:results in 24 hours ;)
JSR, With you're level of epoxy usage , I think you need to invest in an industrial composite curing oven :lol:

Posted: Sat Apr 18, 2009 7:10 am
by jackssmirkingrevenge
SubsonicSpud wrote:Good to see the problem is found (hopefully) :D
I also took the opportunity to make everything smaller and neater in an all-stainless body that can be used in a complete launcher if it works.
JSR, With your level of epoxy usage, I think you need to invest in an industrial composite curing oven :lol:
I've often though of using the kitchen oven to speed things up but it can't really be trusted to keep a reliable temperature and since I use a lot of plastics in my projects, it's better to err on the side of caution and be patient ;)

Posted: Sat Apr 18, 2009 7:30 am
by SubsonicSpud
jackssmirkingrevenge wrote: I've often though of using the kitchen oven to speed things up but it can't really be trusted to keep a reliable temperature and since I use a lot of plastics in my projects, it's better to err on the side of caution and be patient ;)
A heater lamp in an insulated box is a good way of doing it, the sort of thing they use for hatching eggs.

Posted: Sat Apr 18, 2009 2:12 pm
by SPG
Jack what's your flow like out of the HP tnak? And also your spring weight? Could it be the gas is expanding enough to overcome the spring and your flatulence? I wondered if turning your flow right down might make a difference. Also if your spring weight is such you're popping at a low pressure doesn't it defeat the object of HPA anyway?

Posted: Sat Apr 18, 2009 2:12 pm
by jackssmirkingrevenge
Some pictures of the latest version, can't wait to try it out:

Posted: Sat Apr 18, 2009 3:06 pm
by Lentamentalisk
Oh god that is beautiful. Honestly, that is looking amazingly close to professional now. Nothing says "well built" like a shiny piece of steel pipe :)