combustion airsoft pistol

Miniature guns are novelty custom, unique, and sometime downright crude! Common construction materials often include pill bottles or pens. Show us your work!
blackhawk13
Private 3
Private 3
Posts: 41
Joined: Tue Sep 22, 2009 8:30 pm

Sun Sep 27, 2009 7:50 pm

i used a coke bottle as the chamber. it runs on hairspray and a standard sparker. the barrel unscrews to fuel and a 6mm airsoft bb can be breach loaded. i put a small notch in the barrel right in the breach so the bb will stay put. you can see a large blue flash when it fires but it doesnt fire reliably even when i use the same amount of fuel. it is so light that it has the same kick as a .22lr pistol
blackhawk13
Private 3
Private 3
Posts: 41
Joined: Tue Sep 22, 2009 8:30 pm

Sun Sep 27, 2009 7:54 pm

pics are not working. here is a link to my album on facebook

http://www.facebook.com/album.php?aid=2 ... 6097c886b5
User avatar
grock
Specialist 2
Specialist 2
Posts: 231
Joined: Mon Dec 29, 2008 2:59 pm

Sun Sep 27, 2009 9:10 pm

dude. your going way overkill on your chamber. a longer barrel would certainly help performance, not a bad first guy though. if you want to fix the reliability issue, try using your breath or a small fan to vent the chamber out between shots.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 25745
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 73 times
Been thanked: 48 times

Donating Members

Sun Sep 27, 2009 9:41 pm

User avatar
rcman50166
Corporal 2
Corporal 2
Posts: 697
Joined: Sat Jan 19, 2008 7:11 pm
Location: Bethel, CT
Contact:

Sun Sep 27, 2009 10:25 pm

maybe not as much as a .22 pistol. Using the law of conservation of energy it would be calculated the the muzzle velocity of the bb (@ .25g) must be 3045 ft/s :shock:
Image
User avatar
grock
Specialist 2
Specialist 2
Posts: 231
Joined: Mon Dec 29, 2008 2:59 pm

Sun Sep 27, 2009 10:40 pm

rcman50166 wrote:maybe not as much as a .22 pistol. Using the law of conservation of energy it would be calculated the the muzzle velocity of the bb (@ .25g) must be 3045 ft/s :shock:
but wouldn't that only be true if you assumed that the mass of the .22 weapon was the same as the mass of the airsoft gun?
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 25745
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 73 times
Been thanked: 48 times

Donating Members

Sun Sep 27, 2009 10:57 pm

grock wrote:but wouldn't that only be true if you assumed that the mass of the .22 weapon was the same as the mass of the airsoft gun?
Agreed, I could see how the perceived recoil could be seen as being equivalent to a 22lr.

How are you fuelling? On such a small launcher, lighter refil can + syringe would be ideal.

Image

Calculate 4% of your chamber volume and you should get proper ignition every time. Also, remember that you have to vent the chamber after each firing to allow the air to be replenished.
blackhawk13
Private 3
Private 3
Posts: 41
Joined: Tue Sep 22, 2009 8:30 pm

Mon Sep 28, 2009 5:47 am

the reason it kicks so much is that it is so light. the heaviest part is the 1 1/2 in pvc grip. i plan to switch to propane but i am still new to spudguns. this time last year the best i had was a 1 1/2 in tank and a 1/2 in ball valve. the bbs that i am using are .12g because thats all i have
User avatar
rcman50166
Corporal 2
Corporal 2
Posts: 697
Joined: Sat Jan 19, 2008 7:11 pm
Location: Bethel, CT
Contact:

Mon Sep 28, 2009 11:35 am

grock wrote:
rcman50166 wrote:maybe not as much as a .22 pistol. Using the law of conservation of energy it would be calculated the the muzzle velocity of the bb (@ .25g) must be 3045 ft/s :shock:
but wouldn't that only be true if you assumed that the mass of the .22 weapon was the same as the mass of the airsoft gun?
No the mass of the weapon itself determines how the kick feels, whether it accelerates or jerks. However the power of the kick is all determinant on the time it takes to recoil. Either way the same amount of energy is being absorbed.
Image
User avatar
VH_man
Staff Sergeant 4
Staff Sergeant 4
Posts: 1827
Joined: Sat Dec 09, 2006 6:00 pm
Location: New Hampshire

Mon Sep 28, 2009 7:06 pm

haha looks pretty good.

Like Said before, Definitely use a syringe. It will help ALOT.

That and In my experience, the kick felt with small-bore combustion like that is due to the constriction of the barrel. You will find that the kick is the same with and without the BB loaded, and if you had some way of doing High speed photography, You'd be able to see that the kick your getting is being achieved FAR after the BB has left.
blackhawk13
Private 3
Private 3
Posts: 41
Joined: Tue Sep 22, 2009 8:30 pm

Mon Sep 28, 2009 7:13 pm

thanks. my friend is getting me the stuff to run this off butane. i have some i use to refill lighters. what is stronger butane or propane? also the kick is fun. i tested this outside today. i shot a .12 bb at a shotgun clay point blank and it punched out the center. the only guns i have that can do that are over 350fps. when i shoot it i can see that it is faster than my 350fps pistol but not faster than my 430fps rifle. of 2 shots i saw 1 was about 350 and the other was about 380. i cant wait to get this running on butane
User avatar
maverik94
Corporal
Corporal
Posts: 558
Joined: Wed Jan 21, 2009 4:48 pm

Mon Sep 28, 2009 7:21 pm

very ghetto, Me-likes, lol, I like the pen as the barrel!
"You can't be friends with anyone if you aren't friends with yourself."
"I'd rather be hated for who I am, than loved for who I'm not." -André Gide
Give me a lever long enough, and a fulcrum on which to place it and I shall move the world.
–Archimedes
Defeat is always momentary.
–Carl Denham

Current Project: None, I'm in Spudremission.
blackhawk13
Private 3
Private 3
Posts: 41
Joined: Tue Sep 22, 2009 8:30 pm

Mon Sep 28, 2009 7:24 pm

it was the only thing i had that fit an airsoft pellet. but thanks. i plan to take some bottle caps and make some other barrels. i want to make a barrel for .177 bbs/pellets and a nerf dart barrel
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 25745
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 73 times
Been thanked: 48 times

Donating Members

Mon Sep 28, 2009 10:10 pm

propane is technically a little better than butane but you wouldn't notice the difference...
blackhawk13
Private 3
Private 3
Posts: 41
Joined: Tue Sep 22, 2009 8:30 pm

Tue Sep 29, 2009 6:17 pm

i just shot this and i finally figuredout my problem. the fuel was not mixing properly i waited a few minutes after loading it and it worked great. 400fps :D
Post Reply