http://i813.photobucket.com/albums/zz59/ONKinetics/Colourful%20Fluid%20Dynamics/CFD.png Ooh, pretty pictures. I think I speak for just about everyone here when I say that I'd like the design of launcher systems to be less of a crapshoot. We have a few narrowly applicable tools like GGDT, HGDT, and ...

That's actually a pretty neat little toy. Is the mechanism still easy to trigger at 850psi? Also, despite my aversion to pneumatics of any kind, I feel an inexplicable urge to build one :lol: Given my current supply situation though, I would have a choice of pressurizing it with either hydrogen or o...

Well, this thread turned into a total cluster**** while I was gone... Just about everything said since my previous post is in some way wrong or ambiguous, including JSR's advice on the ideal mix ratio (using the mix ratio he proposed will lead to low performance and high risk of detonation, and his ...

Firstly, if you don't already have HGDT and GasEq, get them - they should be considered the bare minimum for designing any kind of combustion launcher, and they're both free and very easy to use. Using oxygen/propylene (MAPP isn't actually made any more) will actually produce nearly identical pressu...

As pointed out by other posters, needle valves are flow regulators, probably not what you're looking for. Most general purpose gas pressure regulators actually are inline, which is why your searches for "inline" regulators are turning up many results :wink: . If you're in the USA, Mcmaster-Carr is a...

Here's the video for the first shot, where I fired a 1/4" bearing ball through a 3/8" mild steel plate: http://i813.photobucket.com/albums/zz59/ONKinetics/Stage1/th_Stage1S2.mp4 I decided to do a better job on the barrel end assembly after breaking the first one, and came up with this: http://i813.p...

What does a loose fitting barrel mean? Also, thoughts on flow coefficient, results seem constant at all percentages. Thanks The projectile is loose in the barrel. In this case, about 7.5% of the barrel cross section is unoccupied by the projectile, resulting in significant blowby, thereby reducing ...

Unless this gun is a coaxial design, the "inner diameter" field should be set to zero - that's the outer diameter of an inner pipe running through the chamber (and thus the inner diameter of the air volume in the chamber). Five grams seems a high mass for a "BB" of 0.173" diameter (not actually achi...

Any dead space in between the piston and projectile has a effect but how much...who knows Ooh, I know the answer to that question: Me, because I can model it with a high degree of accuracy. It's not a hugely complicated problem, as gas dynamics goes, and admits an (approximate) analytical solution,...

Excuse my lack of knowledge but how does this compare to conventional weapons as far as penetration? For example if an Ak47 or US equivalent was fired at the steel plate what would the result be? Or what weapon does this sort of penetration compare to? This plate was mild steel, and thus not direct...

what is the target made of?

The target is 3/8" steel plate.

Do you think the new sabot had something to do with it or that you just underestimated its penetrative capabilities? The WARTL shot I was basing my estimate on must have been slower than I initially thought. It wasn't measured directly (it also, obviously, didn't need a sabot, as WARTL is 1/4" bore...

I've done a lot of work on this launcher over the break, on seals, burst disks, sabot catching, and the vacuum system for the barrel (which now works perfectly). The first shot of the break was fired today, using an optimized UHMWPE sabot weighing 3.66g to carry a 1/4" hardened steel ball (the mass ...

You know, if you're bound and determined to never learn how to use ANSYS, you could use Solidworks' built in FEA to do a stress analysis of the darts. Find the maximum acceleration of the dart in the barrel, then model the dart upright (nose pointing up) under gravity equivalent to that acceleration...

Is that 0.760" exactly? I have some 7.5mm dia round HSS blanks knocking about, could make a couple of aluminum finned darts if you want. What's the inner diameter of your sabot catcher? That is 0.760"±0.0005". I find that making the projectile body to 0.759" gives a nice smooth slide. I'd probably ...