.1835 C:B Ratio Acceptable for Pneumatics?
I'm working on a coaxial piston cannon with a 2.5 inch barrel and 3 inch chamber, at 48 inches long I calculated the volume of the chamber to be 43.25 square inches and the barrel to be 235.6, giving a B:C ratio of .1835. Is this within acceptable range? The reason I'm using 2.5 inch for the barrel is, first, so I can shoot tennis balls (obvious) but more importantly so that I can have a changeable barrel system.
Thanks,
Jabingo19
Thanks,
Jabingo19
- inonickname
- First Sergeant 4
- Posts: 2606
- Joined: Sun Dec 07, 2008 3:27 am
What pressures and valve are you using, and what kind of performance are you looking for
PimpAssasinG wrote:no im strong but you are a fat gay mother sucker that gets raped by black man for fun
- Technician1002
- Captain
- Posts: 5189
- Joined: Sat Apr 04, 2009 11:10 am
Please correct the units of measure and maybe we can understand the problem. Volume is a cubic measurement. Area is a square units measurement. Don't send me to the store for 3 square inches of milk.
Haha yeah... Thanks Technician, sorry 43.25 and 235.6 cubic inches. As far as performance, I'm looking for, well, good performance. I certainly don't want to be limited by the lack of air to push it. I was looking on spudwiki and it said that according to GGDT the ideal was between .2 and .3, with changeable barrels as well I know that with a golf ball barrel and others it would be fine, I just want to know if it will do well with the tennis ball also.
Thanks
Thanks
- jackssmirkingrevenge
- Five Star General
- Posts: 26179
- Joined: Thu Mar 15, 2007 11:28 pm
- Has thanked: 543 times
- Been thanked: 319 times
How do you plan changing barrels in a co-ax?
I would suggest you play with GGDT, it will let you know if the power range is acceptable for your requirements for the pressure you intend to work with.
I would suggest you play with GGDT, it will let you know if the power range is acceptable for your requirements for the pressure you intend to work with.
hectmarr wrote:You have to make many weapons, because this field is long and short life
- Gun Freak
- Lieutenant 5
- Posts: 4971
- Joined: Mon Jan 25, 2010 4:38 pm
- Location: Florida
- Been thanked: 7 times
.2 and .3 make no sense for a PVC pneumatic... You must have read it wrong... Performance probably wont be great in my opinion.
OG Anti-Hybrid
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna" ■ M16 BBMG ■ Pengun ■ Hammer Valve Airsoft Sniper ■ High Pressure .22 Coax
Holy Shat!
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna" ■ M16 BBMG ■ Pengun ■ Hammer Valve Airsoft Sniper ■ High Pressure .22 Coax
Holy Shat!
- jackssmirkingrevenge
- Five Star General
- Posts: 26179
- Joined: Thu Mar 15, 2007 11:28 pm
- Has thanked: 543 times
- Been thanked: 319 times
It depends on the other launcher parameters - if you have a burst disk, long barrel and high pressure, performance will be quite impressive even with a 0.2 C:B ratio.Gun Freak wrote:You must have read it wrong... Performance probably wont be great in my opinion.
Por ejemplo:
- Attachments
-
- lowcbggdt.PNG (34.14 KiB) Viewed 2828 times
hectmarr wrote:You have to make many weapons, because this field is long and short life
Thanks Jack, I would play with GGDT but I have no idea how to... And Gun Freak I am capable of reading, and it said "Suggestively, the optimal C:B ratio for pneumatic guns, as predicted by GGDT are in the vicinity of 0.2~0.3" Also Jack, once I get some rough plans drawn up I'll post a pic.
- jackssmirkingrevenge
- Five Star General
- Posts: 26179
- Joined: Thu Mar 15, 2007 11:28 pm
- Has thanked: 543 times
- Been thanked: 319 times
Download it and learn, it's worth the effort.Jabingo19 wrote:Thanks Jack, I would play with GGDT but I have no idea how to...
Here's a more realistic model of your coaxial, about as much power a 3 round burst from a 9mm submachinegun
- Attachments
-
- 150psicoaxggdt.PNG (35.41 KiB) Viewed 2814 times
hectmarr wrote:You have to make many weapons, because this field is long and short life
Also, I don't know if you have any experience or whatnot, but is some sort of barrel support at the bottom of the coax necessary? At the end of the barrel is it necessary to have that supported so it doesn't wobble when sealing against the piston?
- jackssmirkingrevenge
- Five Star General
- Posts: 26179
- Joined: Thu Mar 15, 2007 11:28 pm
- Has thanked: 543 times
- Been thanked: 319 times
Depends on how rigid the barrel is and how rigidly it is mounted, how long it is, how well centred it is, what pressure you're using...
hectmarr wrote:You have to make many weapons, because this field is long and short life
- jackssmirkingrevenge
- Five Star General
- Posts: 26179
- Joined: Thu Mar 15, 2007 11:28 pm
- Has thanked: 543 times
- Been thanked: 319 times
4 feet is a bit much, I would put spacers. Could be as simple as three bolts each at 120 degrees from eachother at the breech, will also make a useful stop you prevent you from pushing ammunition into the chamber.
hectmarr wrote:You have to make many weapons, because this field is long and short life
- Gun Freak
- Lieutenant 5
- Posts: 4971
- Joined: Mon Jan 25, 2010 4:38 pm
- Location: Florida
- Been thanked: 7 times
The bolts have to be sealed though, or else air will leak out the barrel.
OG Anti-Hybrid
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna" ■ M16 BBMG ■ Pengun ■ Hammer Valve Airsoft Sniper ■ High Pressure .22 Coax
Holy Shat!
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna" ■ M16 BBMG ■ Pengun ■ Hammer Valve Airsoft Sniper ■ High Pressure .22 Coax
Holy Shat!