Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 51 users online :: 2 registered, 0 hidden and 49 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: farcticox1, Google Adsense [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Semi-auto airsoft gun - pneumatic cylinder as air chamber

This area is for the discussion of BB or airsoft sub machine guns, and or other small arms such as pellets.
Sponsored 
  • Author
    Message

Semi-auto airsoft gun - pneumatic cylinder as air chamber

Unread postAuthor: piotrekwyso » Tue Oct 23, 2018 2:51 pm

Hi! I am Piotr and this is my first post on SpudFiles.
I am building semi-auto magazine-fed airsoft rifle with hop-up. I have recently came up with an idea of using pneumatic cylinder for reloading and as an air chamber.
I have question, whether will it work good or not? and what is recommended air chamber volume. I am using 10 bar air supply and 6mm BBs.

Here are some videos that may help you understand what I mean:
https://www.youtube.com/watch?v=t6ja7UMEkyo (Around 4:15)
https://www.youtube.com/watch?v=SLtjQd2 ... 3Q&index=5
  • 1

Attachments
Diagram.png
Diagram.png (32.25 KiB) Viewed 179 times

piotrekwyso
Private
Private
 
Posts: 2
Joined: Tue Oct 23, 2018 12:58 pm
Country: Poland (pl)
Reputation: 2

Re: Semi-auto airsoft gun - pneumatic cylinder as air chambe

Unread postAuthor: jackssmirkingrevenge » Thu Oct 25, 2018 7:03 am

Welcome to the forum!

What is it with Poland and pneumatic cylinders...

pneumatic-cannon-database/topic20259.html

:D

what is recommended air chamber volume


GGDT is the best tool available to determine such parameters. I suggest you download it and don't hesitate to inquire on the forum if you need help using it.

I have question, whether will it work good or not?


Assuming the "Trigger valve" is a three-way valve that cuts off the air supply and simultaneously vents the QEV pilot chamber, it should work well.

How are you actuating the cylinder? It would be interesting if you could tie the cylinder with the pilot volume, for example the pilot pressure keeps the cylinder in the "closed" position, so that venting the pilot simultaneously opens the QEV while also opening the bolt. The trick would be timing it so that the bolt is not open before the BB has left the barrel...
  • 0

hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 25113
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 137

Re: Semi-auto airsoft gun - pneumatic cylinder as air chambe

Unread postAuthor: piotrekwyso » Thu Oct 25, 2018 11:04 am

Well It may be not quite visible on my drawing, but bolt is open and cylinder is retracted (no pressure) the other end of cylinder is sealed, so it acts as natural spring retracting cylinder. When it is connected to air supply, it will extend pushing qev and nozzle with bb into barrel and nozzle will be pushed into bucking sealing bb ready to shot.

I do not worry about cylinder retracting too soon, because from what i have calculated, bb will exit the barrel in around 0,03 s (550-600 fps estimated). I will maybe put some spring physically retarding bolt opening.

Many thanks for advice and reccomending me this program. As soon as I get home, I will try to calculate this volume, if it happens to be too small, I will have to redesign a little bit my model.

I will make an update around tuesday when all my parts are shipped
  • 1


piotrekwyso
Private
Private
 
Posts: 2
Joined: Tue Oct 23, 2018 12:58 pm
Country: Poland (pl)
Reputation: 2

Re: Semi-auto airsoft gun - pneumatic cylinder as air chambe

Unread postAuthor: jackssmirkingrevenge » Fri Oct 26, 2018 5:18 am

piotrekwyso wrote:Well It may be not quite visible on my drawing, but bolt is open and cylinder is retracted (no pressure) the other end of cylinder is sealed, so it acts as natural spring retracting cylinder. When it is connected to air supply, it will extend pushing qev and nozzle with bb into barrel and nozzle will be pushed into bucking sealing bb ready to shot.


Ahhh I understand it now, the air cylinder is also the firing chamber! It was your post title and I didn't catch that, apologies!

That's very clever, given the relative weight of the chamber assembly vis a vis the BB I think it will be out of the barrel long before the nozzle disengages the bucking.
  • 0

hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 25113
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 137

Return to BB/Airsoft/Pellet Gun Discussion

Who is online

Registered users: farcticox1, Google Adsense [Bot]

Reputation System ©'