Search found 294 matches

by FighterAce
Sun Nov 28, 2021 12:31 pm
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1336

Re: Designing a inline piston pressure regulator - Fluid statics math model

I just finished making the v3 based on hectmarr's design. This is the final arrangement: Regulator nacrt-Model01-00.png The body is 2011 Aluminum, just so it would be easier to machine. Both ports are threaded for G1/8 RegV3AlCuBiPb.jpg Piston is 5,8mm steel rod with 3x1,5mm (6mm OD) O rings RegV3As...
by FighterAce
Wed Nov 17, 2021 2:08 pm
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1336

Re: Designing a inline piston pressure regulator - Fluid statics math model

It would just involve adding a friction component to the equilibrium a freeze frame in time, one when it's fully open one when it's closed but it also involves an arbitrary increase in spring compression when it's open. That's how I've been trying to do it, just to get an idea at what pressure the ...
by FighterAce
Wed Nov 17, 2021 12:26 pm
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1336

Re: Designing a inline piston pressure regulator - Fluid statics math model

It is not so difficult to make the air passage channel. Thanks for posting the pictures. Machining it from a solid block requires a different solution though, this is what I'm working on right now: Regulator nacrt-Model01-00.png I agree with your assumption of friction doubling for a piston of doub...
by FighterAce
Mon Nov 15, 2021 3:26 pm
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1336

Re: Designing a inline piston pressure regulator - Fluid statics math model

This last picture with the 2 O ring piston would be rather hard to fabricate... Brass could be drilled and then soldered shut, leaving the 0,75mm diameter path for the air. I plan on making the regulator body out of AlMgSi0,5 stock (6060 Al) so this is not an option. Note that friction increases a l...
by FighterAce
Sun Nov 14, 2021 3:15 am
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1336

Re: Designing a inline piston pressure regulator - Fluid statics math model

This little pressure regulator, I made it. That looks really nice! I like how the piston is acting like a spool valve, making the output pressure depend only on the spring force. The spring must be very light for 3bar output. Does the input HP pressure actually have no effect on the output LP press...
by FighterAce
Thu Nov 11, 2021 7:11 am
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1336

Re: Designing a inline piston pressure regulator - Fluid statics math model

The issue here (for me at least) is why are you designing a pressure regulator? I’ll be going off topic here, but will give you an answer. You could ask the same why I designed and made my last airgun, the M98b. It was a very complex project involving a QEV design using a piston with a built in che...
by FighterAce
Wed Nov 10, 2021 6:52 am
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1336

Re: Designing a inline piston pressure regulator - Fluid statics math model

I think these are really simple equations, it's not like I'm writing out Navier-Stokes here :D I just don't trust myself in correctly assuming the surfaces on which pressures are acting upon, because I literally have no experience with solving this kind of problems. My major deals with incompressibl...
by FighterAce
Sun Nov 07, 2021 8:55 am
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1336

Designing a inline piston pressure regulator - Fluid statics math model

Hello everyone! I finally found some free time after finishing my undergraduate degree and I'm starting to get back into this hobby. One thing I always wanted to make is a pressure regulator to fill my creations from a external tank. Currently I have a 2l fire extinguisher to use for this purpose. M...
by FighterAce
Fri Mar 25, 2016 11:05 am
Forum: General How-To & Discussion
Topic: AT89S8253 based chronograph
Replies: 10
Views: 4164

Re: AT89S8253 based chronograph

Hey if you think you can reproduce this, go ahead. I couldn't find my last code with m/s to km/h and fps conversion so I'm posting the original one I submitted in paper. Dim A As Byte , Brojac As Word , Broj As Long , Ukup As Long , Time As Single , V As Single , Targ As Iram String * 6 $crystal = 2...
by FighterAce
Tue Jul 22, 2014 7:23 am
Forum: Pneumatic Cannons
Topic: Air Rifle Stock Help
Replies: 6
Views: 1300

Re: Air Rifle Stock Help

I highly recommend carving a stock out of a block of wood. Just make sure you're not using the lowest quality wood. Don't repeat my mistake of putting a lot of work into a wooden stock and then have the wood deteriorate after a few years ;) The best way of carving out the cavities would be with a ro...
by FighterAce
Thu Jul 03, 2014 1:09 pm
Forum: General How-To & Discussion
Topic: AT89S8253 based chronograph
Replies: 10
Views: 4164

Re: AT89S8253 based chronograph

Jack that really reminds me of the first ballistic chronograph designed by Kiryako Arvanetakis. I've had an entire segment about him in my presentation ;) Nice to see the design hasn't been forgotten, or perhaps reinvented? Jimmy, the whole point of my graduation project was using the things I was t...
by FighterAce
Tue Jun 10, 2014 9:20 am
Forum: General How-To & Discussion
Topic: AT89S8253 based chronograph
Replies: 10
Views: 4164

AT89S8253 based chronograph

Last week I've defended my graduation project and got an excellent mark so I guess now I can finally share this project with you. It all started 6 months ago with me choosing the project "Microcontroller based projectile speed measurement". The first thing on the list was designing a frame that woul...
by FighterAce
Tue Jun 11, 2013 5:32 pm
Forum: Pneumatic Cannons
Topic: want to build but plans suck
Replies: 8
Views: 2482

Nice list, I like your style :D The only one I didn't make is the M107. If you're going for a replica straight off the bat, I have to recommend the L96. It has a wide chunky stock you can fit a large air tank into and there is a lot of room in the front for a working magazine feed system. The rifle ...
by FighterAce
Thu Feb 21, 2013 2:07 pm
Forum: Pneumatic Cannons
Topic: Piston design with a built in check valve
Replies: 55
Views: 7225

To answer both of your questions... my mill is actually a hand router. Bosch POF 1200 AE to be precise. I can "mill" stuff only because I've built a special table for it :D I'm currently looking into replacing the paper cones with shrink tubing. However with the ever restricting gun laws in this cou...
by FighterAce
Thu Feb 21, 2013 5:45 am
Forum: Pneumatic Cannons
Topic: Piston design with a built in check valve
Replies: 55
Views: 7225

Thanks JSR :D

I didn't post it here because its still incomplete.