Any one could tell me whats these holes on the baffle are for? Like why isn't the hole/cut mirrored? Wouldn't' it cause non uniform turbulence? My understanding is that the turbulence increases the effect. These ports are commonly known as "mouse holes" and introduce what is essentially an angled j...

The purist in me loves the idea of a port that is actually larger than the bore, with the breech tapering down such that flow into the bore is smoooooth and maximized. But yeah, the realist in me realizes that for the vast majority of cases this is beyond overkill. Hmmm... Let's see if I can come up...

Fantastic replies. Thanks for the interesting thought experiment, D_Hall. That gives me something to mentally chew on. I feel 1 3/8" is where it will probably end up for this one. An interesting thing I noticed is that giant (2 5/8" dia) potatoes break apart at 4X and I'm wondering if the 1" port is...

I don't know what the percentage is. I think It depends on the opening pressure of the piston. Since the work is being done with pressurized gas to open the piston, as soon as it opens all of that working gas suddenly goes to work on the projectile and sends it into orbit. So, it may seem as though ...

I feel that such losses are probably not that significant. Pistons typically have a large surface so they do not require a high pressure to move. Added to that, their travel is usually very limited so the increase in chamber volume relative to the total is minimal.

I wonder if the shape of the B version could also have something to do with it. At least you can solve it by making up for it with more fuel and air. The A version is more like a burst disc configuration. I'd like to have two identical cannons, one using a burst disc and the other using a piston, an...

Some more thoughts on the thought experiment.... It assumes constant density, but this is obviously incorrect. But what DOES density do? In the first moments after the valve opens, not much. Constant density probably isn't a bad approximation. But as the projectile accelerates we know that pressure ...

I was having a bit of a think about this idea and it seems it could be greatly simplified and also made more efficient:



The piston itself becomes the hammer that opens an inline balanced valve.

I was having a bit of a think about this idea and it seems it could be greatly simplified and also made more efficient: https://i.imgur.com/Csm81PX.gif The piston itself becomes the hammer that opens an inline balanced valve. Sorta thinking out loud. Piston be generating air infront of it, as heade...

The trigger you actually draw is the initiator of the recharge of the repeat hybrid. It is the mechanical locking of the piston, which allows it to move to the right, by the action of the spring, and then, to the left by the action of compressed air. To fire, the trigger is the piezoelectric. What ...

His explanation of how it works is dead wrong, the pressure in the two chambers will always equalise. The principle at work is exactly the same as that of a QEV, the force exerted on the piston at the "bulb" end is gas pressure * piston cross sectional area, and at the strut end it's gas pressure * ...

I just finished building a wheeled potato "howitzer" out of spare parts. It works pretty well, although I need to take it somewhere a bit more rural for testing once it's legit to travel around again. 1.jpg 2.jpg Youtube vid: https://youtu.be/ocxYe_j6nOw It's got the standard 2" barrel & 4" chamber ...

Made new piston from long 6mm bolt with head cut off and piece of 10mm thick nylon, works really good. Semi auto is now built in to my old single shot.

Alright guys, at a new host - still sorting a few small things out for transitioning server/settings/etc but our white pages seemed to have immediately disappeared!