Right now am I better of ditching the design I have (using a pressurized chamber and shooting 'squirts' of air from a blowgun valve to launch the darts) or starting again with a whole new design.

I think the blowgun design will serve you well.

Try modelling with the following parameters ...

Ok so I've tried longer barrels (70 cm, do I need longer?) and Upped the pressure to 45 psi (30 psig in the program) but it seems that the projectile simply travels the length of the barrel with some strangely fluctuating velocity
Right now am I better of ditching the design I have (using a ...

Well I'm pissed off at google now, I've heard the term GIGO before, but had forgotten it.

Google decides I must be looking up "gigolo".

Everything JSR said I second, play around with GGDT, try a few things, you'll soon find out it's flaws.

Just had to post a rage against google.
Garbage in ...

jackssmirkingrevenge wrote:Some comments...

Just plain stupid actually. The thing said that the barrel was unnecessarily long too.

shiny455 wrote:with a bit of stuffing around i got it to reach 1.8m/s maybe the program isnt made for such low pressures and velocities

The GGDT site says is has trouble with low pressure guns.

Oh the 28 was an error but it still says it won't leave the barrel.
By dead space you mean dead volume right.

P.s. your profile says your an aussie, high five.

I dunno I'm noob to it so I think you think I'm stupid.
But here goes nothing.


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So i'm still gonna need some designs/help with a tank.
I'm now going for a 75-100 psi tank on recommendations from Jackssmirkingrevenge. I'm only getting messages saying that the projectile has not left the muzzle so i'm hoping with more experimentation with the program I can get success.

No not really you gave me an excellent springboard.

yea but then if you lop off to much you need to buy a new one. you should use GGDT read the instruction on the sit on how to use it and if your using vista run as admin or it wont work.

set the valve to generic, seat dia about 0.5 cm, opening time 15ms and dwell about the same(guessing but should ...

Labtecpower wrote:

Stormling wrote:Thanks for the help.
Do a need a barrel that big though.

depends on when you're satisfied. more barrel = more power (to a certain degree)

So I can just keep cutting of bits till Ii'm at a happy medium with length and power?

Thanks for the help.
Do a need a barrel that big though.

Btw if you could give me some info about the valve in that pic that would be great.

I'll see if a can post up some diagrams of my original design as well.

I'll actually use it but I sorta need the trigger not inline with the tank so I can mount it, thats why I was going with the modified valve.

A diagram of your intended configuration would help us help you ;)

So I'm correct in thinking that if I get a blowgun with a good flow, i pump up the tank ...