Search found 75 matches

by sharpshooter
Thu Jun 22, 2017 4:21 pm
Forum: Pneumatic Cannons
Topic: Rotation mechanism Revolver pneumatic
Replies: 7
Views: 1200

Re: Rotation mechanism Revolver pneumatic

Are you dead set on pnuematics? You could set an Arduino to rotate a stepper or servo X number of degrees Y number of milliseconds after firing. Would only be a few more steps to make it continuous fire after that...
by sharpshooter
Fri Dec 16, 2016 2:22 pm
Forum: Combustion Cannons
Topic: The idea of the dispenser potato gun
Replies: 11
Views: 1978

Re: The idea of the dispenser potato gun

Why not just measure the correct amount of fuel with the syringe, and squirt that into the chamber? Would of course have to find a syringe of appropriate size for your fuel density (ie tiny fractions of an mL for liquids, something larger for gases)
by sharpshooter
Mon Nov 14, 2016 11:33 am
Forum: Pneumatic Cannons
Topic: Shock Pump Recommendations?
Replies: 4
Views: 1088

Re: Shock Pump Recommendations?

I don't there is much of a consensus of one specific pump being the cat's meow. Pumps are pretty much a commodity - some are built a little better, or may last longer, but it basically is a game of 'you get what you pay for'
by sharpshooter
Tue Nov 01, 2016 2:21 pm
Forum: Ammo & Parts
Topic: Is a Non-rated Pipe Safe if I Pressure Tested It?
Replies: 7
Views: 1616

Re: Is a Non-rated Pipe Safe if I Pressure Tested It?

Probably. But maybe not. Depends on what sort of risks you like to take.
by sharpshooter
Mon Oct 31, 2016 1:51 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: BFG #7
Replies: 57
Views: 7926

Re: Semi automatic ideas?

I assume the pneumatic piston on the right side will cycle the bolt automatically?
by sharpshooter
Mon Oct 31, 2016 10:17 am
Forum: Pneumatic Cannons
Topic: Wacky Breechloading Launcher
Replies: 10
Views: 1658

Re: Wacky Breechloading Launcher

Holy cow!! SO many animations! You guys are not helping me avoid buying a lathe.
by sharpshooter
Thu Oct 27, 2016 1:11 pm
Forum: Hybrid Cannons
Topic: A question about pilot pressure.
Replies: 14
Views: 1742

Re: A question about pilot pressure.

You might do some searching on burst disk pressure. Back in the day, I know that there was some testing done when layered tin foil disks were the cats meow. But basically what was discovered is that if the opening pressure is too high, the pressure spike would already be starting to diminish before ...
by sharpshooter
Mon Oct 24, 2016 4:09 pm
Forum: Pneumatic Cannons
Topic: Arrow gun: Barrel length vs fps question.
Replies: 18
Views: 2335

Re: Arrow gun: Barrel length vs fps question.

Still trying to make heads or tails of that first drawing... Where is the chamber? Is it that little area behind the arrow? Or does it not technically have a chamber, and instead the valve is essentially dumping just the air in the line between the tank and valve? And then your 'barrel' actually fit...
by sharpshooter
Fri Oct 21, 2016 3:39 pm
Forum: Pneumatic Cannons
Topic: Piston with off-center barrel?
Replies: 1
Views: 441

Piston with off-center barrel?

Has anyone ever built a piston valve with an off-center valve seat? I am going for a twin barrel configuration, and I want them as close together as possible. But i don't want to use elbows, as that will increase dead volume, and introduce turbulence to the flow. My gut says this should be a non iss...
by sharpshooter
Wed Oct 19, 2016 12:46 pm
Forum: Ammo & Parts
Topic: 3/4" or larger QEV without breaking the bank?
Replies: 4
Views: 1252

Re: 3/4" or larger QEV without breaking the bank?

There's no doubt that I can build the valves, but time is such a limited resource.
by sharpshooter
Tue Oct 18, 2016 10:17 am
Forum: Ammo & Parts
Topic: 3/4" or larger QEV without breaking the bank?
Replies: 4
Views: 1252

3/4" or larger QEV without breaking the bank?

I'm looking for a pair of 3/4" or 1" (20-25mm) QEV valves for a double barrel build. Everything I see that can handle ~200 PSI is over $100 per valve. I was hoping to spend more like $75-100 for the pair. Is this possible? Or am I better off just building some nice pistons?
by sharpshooter
Tue Mar 29, 2016 11:28 pm
Forum: Ammo & Parts
Topic: Calculate projectile data?
Replies: 5
Views: 1683

Re: Calculate projectile data?

:oops: Oh duh
by sharpshooter
Tue Mar 29, 2016 10:42 pm
Forum: Ammo & Parts
Topic: Calculate projectile data?
Replies: 5
Views: 1683

Re: Calculate projectile data?

Well I'll be. I had no idea. But it doesn't have any energy output - just distance/height. Although... I could probably work out the final velocity from distance/time. While I was hoping for something much more automated, that may have to do. I did see that NASA page before, and frankly I am too spo...
by sharpshooter
Mon Mar 28, 2016 12:21 pm
Forum: Ammo & Parts
Topic: Calculate projectile data?
Replies: 5
Views: 1683

Calculate projectile data?

GGDT/HGDT have made the calculations up to the point of leaving the barrel a dream. But what about after? High school physics was a loooonggg time ago. I found this write up http://www.dummies.com/how-to/content/calculate-the-range-of-a-projectile-fired-at-an-an.html , but it appears to be rather si...
by sharpshooter
Wed Mar 09, 2016 10:45 am
Forum: Ammo & Parts
Topic: Need CNC parts?
Replies: 1
Views: 810

Need CNC parts?

Due to life being life, I have found myself with too much free time, and need to fill it with something productive. I want more practice in my new 3D modeling program (Fusion360 - its awesome so far), as well as tweaking my CNC workflow. My machine can handle parts up to 30" x 18", with a Z travel o...