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 90 users online :: 5 registered, 0 hidden and 85 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

My (hopefully easy and viable) piston design

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

My (hopefully easy and viable) piston design

Unread postAuthor: Pilgrimman » Thu Jul 19, 2007 1:51 pm

Image

If the image doesn't work, forgive me. I've never hosted one on a forum before... :oops: I added a link to the host site... although I've never linked on a forum either...

Anyway, the piston is made almost entirely of PVC, except the barrel sealing rubber, and the fill valve. To get a better tolerance between the 1" and 1 1/4", I might wrap it in electrician's tape. The reservoir will be bigger, I just made it small in the image for simplicity. Also, I omitted the pilot valve from the image, as it should be obvious where IT goes... :lol:

Thoughts and feedback are appreciated!

Edit: **** neither one worked... Could someone help me???

[/url]http://img403.imageshack.us/my.php?image=pistondesignkn9.png[url][/url]
  • 0

User avatar
Pilgrimman
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 481
Joined: Thu Jun 28, 2007 1:10 pm
Location: Grants Pass, OR
Reputation: 0

Unread postAuthor: paaiyan » Thu Jul 19, 2007 1:54 pm

<a href="http://img403.imageshack.us/my.php?image=pistondesignkn9.png" target="_blank">Link to picture.</a>

I don't really know how all the bbcode stuff works, I use oldschool HTML.

EDIT: I'm not sure I completely understand how it's supposed to work, can you clarify a bit?
  • 0

Last edited by paaiyan on Thu Jul 19, 2007 2:04 pm, edited 1 time in total.
"Who ever said the pen was mightier than the sword, obviously, never encountered automatic weapons."
-General Douglass MacArthur

Read my dog's blog - Life of Kilo
User avatar
paaiyan
Major General
Major General
 
Posts: 2140
Joined: Wed Dec 27, 2006 10:03 pm
Location: Central Oklahoma
Country: United States (us)
Reputation: 1

Unread postAuthor: iknowmy3tables » Thu Jul 19, 2007 2:04 pm

that may not open cause the sufacearea of presure behind he piston is equal to the barrel size well almost, but the vacum of the barrel in holding it on and their in almost no presure ablible to push the piston back, you have to mesure the forces on both sides based on how much of the area is exposed to presure, the barrel has no presure inside so its side has less
  • 0


iknowmy3tables
Major General
Major General
 
Posts: 1558
Joined: Fri Dec 15, 2006 3:57 pm
Location: maryland
Country: United States (us)
Reputation: 0

Unread postAuthor: Gepard » Thu Jul 19, 2007 2:04 pm

Code: Select all
 [url]http://url[/url] or [url=http://url]URL text[/url]


Michael
  • 0


Gepard
Captain
Captain
 
Posts: 342
Joined: Mon Jun 18, 2007 11:12 am
Reputation: 0

Unread postAuthor: spudthug » Thu Jul 19, 2007 2:15 pm

so uhh...wheres the chamber going to be :wink:
  • 0

4" piston valved cannon-half done..( i spilt my cement...)

Hybrid- 75% done. need to build propane holder and drill/tap sparkplug hole..
User avatar
spudthug
Brigadier General
Brigadier General
 
Posts: 936
Joined: Mon Feb 26, 2007 9:02 pm
Location: johnsonburg, Pa USA
Reputation: 0

Unread postAuthor: Pilgrimman » Thu Jul 19, 2007 2:25 pm

Everyone look at Paaiyan's link for my image, as I'm too much of an ignoramus to link to it properly :oops:

@Paaiyan
Fill it up through the valve, the air pushes the orange foreward, which is the piston. The air bleeds around the orange tube into the blue. Since the endcap on the orange pipe is wider than the pipe itself, in terms of surface area, it SHOULD open when the area behind the piston is piloted. This design is meant for simplicity of construction and low cost, as I have no access to a lathe or other tools.

@iknowmy3tables
The drawing of the endcap on the piston does not really convey it's surface area. The endcaps for the brand of PVC I use are significantly thicker than most. Example: The outside diameter on a 1 1/4" cap of this brand is too much for it to fit down a 2" pipe! That's at least 1/2" inch thick at it's widest point! For this reason, the surface area SHOULD be great enough to overcome the back of the piston.

Thanks to all who responded! I'm going to read more on piston valves, and potentially update my design!
  • 0

User avatar
Pilgrimman
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 481
Joined: Thu Jun 28, 2007 1:10 pm
Location: Grants Pass, OR
Reputation: 0

Unread postAuthor: iknowmy3tables » Thu Jul 19, 2007 2:34 pm

its still not big enough unless the endcap is lightly sealed against the 2" pipe, and the 1" in the 1 1/4" is just to guide it then thhere is not enough suface area diffrence from the barrel suface area to operate
  • 0


iknowmy3tables
Major General
Major General
 
Posts: 1558
Joined: Fri Dec 15, 2006 3:57 pm
Location: maryland
Country: United States (us)
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: spudthug » Thu Jul 19, 2007 2:41 pm

i still want to know where your chamber is going to be and you cant build a gun without a chamber so you should stop asking questions until u figure out where your chamber is...
  • 0

4" piston valved cannon-half done..( i spilt my cement...)

Hybrid- 75% done. need to build propane holder and drill/tap sparkplug hole..
User avatar
spudthug
Brigadier General
Brigadier General
 
Posts: 936
Joined: Mon Feb 26, 2007 9:02 pm
Location: johnsonburg, Pa USA
Reputation: 0

Unread postAuthor: lukemc » Thu Jul 19, 2007 2:46 pm

i think this should be stickied somewhere Forum code
  • 0

"Those who are different change the world. Those who are the same keep it that way"
User avatar
lukemc
Colonel
Colonel
 
Posts: 565
Joined: Sun Feb 25, 2007 8:48 am
Location: NY
Reputation: 0

Unread postAuthor: Pilgrimman » Thu Jul 19, 2007 7:22 pm

@spudthug
The 2" part will probably be longer, and have a reservoir connected to it. I only showed the piston housing and design for simplicity, and the fact that I lack any ability to animate well. :cry:

Edit: Thanks to whoever posted the forum code link! Here's my next attempt...

http://img403.imageshack.us/my.php?image=pistondesignkn9.png
  • 0

User avatar
Pilgrimman
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 481
Joined: Thu Jun 28, 2007 1:10 pm
Location: Grants Pass, OR
Reputation: 0

Return to Pneumatic Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'