Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 79 users online :: 3 registered, 0 hidden and 76 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

self venting combustion

A place to ask general spud cannon related questions.
Sponsored 
  • Author
    Message

self venting combustion

Unread postAuthor: singularity » Thu Jul 05, 2007 6:15 pm

i had this idea a while ago but i didn't post it becuase it seemed like it would because i thought it would be to complicated to be worth it but i have some extra time so here we go...

<img src="http://i78.photobucket.com/albums/j85/irwinner_2006/combustion.jpg">

its a pretty basic concept build a combustion with in a coaxial and use the barre as a combustion camber. now the coaxial would be constructed like a normal pneumatic piston or diaphragm gun, and it would store air just like one to... accept there would be no pilot valve. the force of the combustion gases would force the piston back ward both giving the projectile a little extra speed and completely venting the camber. of course for this to work you would need a consistent combustion (metered propane) and would need to get the air pressure just right. im sure i forgot something so feel free to ask any questions...
  • 0

be sure to check out my <a href="http://www.spudfiles.com/forums/ak-style-airsoft-vortex-gun-t10959.html">AK Styled Vortex Gun</a> and my <a href="http://www.spudfiles.com/forums/at-4-t9627.html">AT-4 Rocket</a>

upcoming projects... finalized clip fed BBMG and ball point pen sniper
User avatar
singularity
Brigadier General
Brigadier General
 
Posts: 982
Joined: Mon Jun 26, 2006 10:53 pm
Location: someplace
Reputation: 0

Unread postAuthor: Jumpin Jehosaphat » Thu Jul 05, 2007 6:21 pm

You would transfer kinetic energy for moving the piston that could have been used to propel the projectile. Interesting idea though, it seems like it would work, but it would sacrifice some power I think.
  • 0

User avatar
Jumpin Jehosaphat
Sergeant Major
Sergeant Major
 
Posts: 188
Joined: Wed Jun 06, 2007 8:20 pm
Reputation: 0

Unread postAuthor: sandman » Thu Jul 05, 2007 7:53 pm

everything happens so fast that i doubt that this would help. But i am very intrigued by the thought :!:
  • 0


sandman
Colonel
Colonel
 
Posts: 672
Joined: Thu Mar 15, 2007 6:59 pm
Reputation: 0

Unread postAuthor: singularity » Thu Jul 05, 2007 8:32 pm

do you think the use of a burst disc would help?
  • 0

be sure to check out my <a href="http://www.spudfiles.com/forums/ak-style-airsoft-vortex-gun-t10959.html">AK Styled Vortex Gun</a> and my <a href="http://www.spudfiles.com/forums/at-4-t9627.html">AT-4 Rocket</a>

upcoming projects... finalized clip fed BBMG and ball point pen sniper
User avatar
singularity
Brigadier General
Brigadier General
 
Posts: 982
Joined: Mon Jun 26, 2006 10:53 pm
Location: someplace
Reputation: 0

Unread postAuthor: Jumpin Jehosaphat » Thu Jul 05, 2007 9:28 pm

I'm not sure... It seems like you would have to do some ridiculously accurate calculations for this to work without significant power loss. I also think the vent chamber would block off where you probably want your propane meter to go.
  • 0

Image
User avatar
Jumpin Jehosaphat
Sergeant Major
Sergeant Major
 
Posts: 188
Joined: Wed Jun 06, 2007 8:20 pm
Reputation: 0

Unread postAuthor: singularity » Thu Jul 05, 2007 10:53 pm

that is easy to fix, just move the ammo up and have the propane meter more towards the front of the gun... im thinking metered hydrogen would work better for this...
  • 0

be sure to check out my <a href="http://www.spudfiles.com/forums/ak-style-airsoft-vortex-gun-t10959.html">AK Styled Vortex Gun</a> and my <a href="http://www.spudfiles.com/forums/at-4-t9627.html">AT-4 Rocket</a>

upcoming projects... finalized clip fed BBMG and ball point pen sniper
User avatar
singularity
Brigadier General
Brigadier General
 
Posts: 982
Joined: Mon Jun 26, 2006 10:53 pm
Location: someplace
Reputation: 0

Unread postAuthor: Spedy » Thu Jul 05, 2007 11:39 pm

Heh, makes me think of a 2-stage hybrid. first combustion, then air pressure.
Very nice idea, I want to see this ina cannon some time.
  • 0


Spedy
Staff Sergeant
Staff Sergeant
 
Posts: 108
Joined: Thu Jun 21, 2007 4:15 pm
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: psycix » Fri Jul 06, 2007 3:49 am

This is a very interesting design wich makes me think of other things.

What about having 2 chambers.
Chamber A is connected to the barrel. (barrel may be bolt-action reloading)
Chamber B is larger and holds a fuel mix under some pressure. It is connected to A with a valve between.

-A is filled up -> fires projectile
-open valve for a short time -> Mixture flows from B to A
-Bolt action reload
-Fire again!
With a large clip for projectiles and a large tank B you would be able to do some repeated fire for a long time.
  • 0

User avatar
psycix
Donating Member
Donating Member
 
Posts: 3684
Joined: Mon Jun 25, 2007 7:12 am
Location: The Netherlands
Reputation: 0

Unread postAuthor: TechnoMancer » Fri Jul 06, 2007 6:15 am

but the mixture in B is more unstable than fuel on its own and air on its own and so you run the risk of tank B blowing up!!!
  • 0


TechnoMancer
Corporal
Corporal
 
Posts: 64
Joined: Mon Jul 02, 2007 4:58 am
Location: Christchurch New Zealand
Reputation: 0

Unread postAuthor: psycix » Fri Jul 06, 2007 2:06 pm

Tank B can be risky yes, but ive seen other topics with a bulk tank for quick loading.
A solution might be to put a huge (but weak) burst disk on tank B, if it blows, it will just send alot of hot air someway.
But a fuel mix will never ignite without any reason. Theres no ignitor in it and just make sure sparks are impossible.

Isnt that a good idea?
  • 0

User avatar
psycix
Donating Member
Donating Member
 
Posts: 3684
Joined: Mon Jun 25, 2007 7:12 am
Location: The Netherlands
Reputation: 0

Unread postAuthor: dongfang » Wed Jul 11, 2007 5:35 pm

Hi

How about a fast, big and light check valve in a chamber that is too small by the usual C:B rules: The projectile, and the inertia of the gases in the barrel will suck the valve open and draw fresh air into the chamber ....

Regards
Soren
  • 0

User avatar
dongfang
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 448
Joined: Sun Aug 27, 2006 8:02 am
Location: Switzerland
Reputation: 0

Unread postAuthor: psycix » Thu Jul 12, 2007 5:05 am

That will decrese performance ALOT
And sometimes it may be so much the projectile will be stopped in the barrel or even sucked back in the chamber then.
  • 0

User avatar
psycix
Donating Member
Donating Member
 
Posts: 3684
Joined: Mon Jun 25, 2007 7:12 am
Location: The Netherlands
Reputation: 0

Unread postAuthor: iknowmy3tables » Thu Jul 12, 2007 6:55 am

hey is the air part pressurized then that would be really cool
  • 0


iknowmy3tables
Major General
Major General
 
Posts: 1558
Joined: Fri Dec 15, 2006 3:57 pm
Location: maryland
Country: United States (us)
Reputation: 0

Unread postAuthor: boilingleadbath » Thu Jul 12, 2007 12:10 pm

psycix, depending on the amount of turbulence in the inlet stream, such a system may only require a B:C ratio of (1.25+1):1.
That's basically a .45:1 C:B ratio... which, even without the vent in the back, only decreases muzzle energy ~20%.

With a vent in the back, the 'negative' pressure will not be as great, and so the decrease in muzzle energy will be much less pronounced.

Of course:
1) The prior statements are for a best-case scenario.
2) This has been discussed before
3) It does not belong in this thread
  • 0

User avatar
boilingleadbath
Moderator
Moderator
 
Posts: 1642
Joined: Sat Mar 12, 2005 10:35 pm
Location: Pennsylvania, USA
Reputation: 0

Unread postAuthor: psycix » Fri Jul 13, 2007 6:11 am

boilingleadbath wrote:psycix, depending on the amount of turbulence in the inlet stream, such a system may only require a B:C ratio of (1.25+1):1.
That's basically a .45:1 C:B ratio... which, even without the vent in the back, only decreases muzzle energy ~20%.

With a vent in the back, the 'negative' pressure will not be as great, and so the decrease in muzzle energy will be much less pronounced.

Of course:
1) The prior statements are for a best-case scenario.
2) This has been discussed before
3) It does not belong in this thread


Oh yeah I fergot that the negative pressure would be removed a bit because of the venting in the back. :) Without that I would vacuum a bit.
  • 0

User avatar
psycix
Donating Member
Donating Member
 
Posts: 3684
Joined: Mon Jun 25, 2007 7:12 am
Location: The Netherlands
Reputation: 0

Next

Return to General Spud Cannon Related

Who is online

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot]

Reputation System ©'