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 38 users online :: 4 registered, 0 hidden and 34 guests


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

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

The Team
Administrators
Global Moderators
global_moderators.png CS

Hybrid Piston Valve Design

Post questions and info about hybrid (compressed gas with fuel) powered cannons here. This includes discussion about fuels, ratios, ignition systems, build types, safety, and anything else relevant.
Sponsored 
  • Author
    Message

Hybrid Piston Valve Design

Unread postAuthor: frocksie » Mon Nov 30, 2009 10:14 pm

I am designing a hybrid piston cannon and I would like to attain 8x mixes.

The design is an improvement of this design. I am wondering what material I should use for the chamber of the cannon.

I either want to use 6061 aluminum or steel. Both have pros and cons.

6061 aluminum will not rust and is lightweight, but it loses strength when welded.

Steel on the other hand is heavy and rusts, but is easy to weld and does not lose significant strength when welded.

Thoughts?

Note: The scale of the drawing is noted in the picture comments
  • 0

Attachments
SCAN0029.JPG
The chamber diameter at its widest is 2.5" and ~5" long.
SCAN0029.JPG (20.32 KiB) Viewed 1257 times
“He who controls the present, controls the past. He who controls the past, controls the future.”
-George Orwell
User avatar
frocksie
Sergeant
Sergeant
 
Posts: 91
Joined: Fri Mar 23, 2007 2:05 pm
Location: Maine
Reputation: 0

Unread postAuthor: Moonbogg » Tue Dec 01, 2009 3:58 am

Use aluminum and employ bolted connections. You can build it entirely yourself this way by drilling and tapping holes. I say base the design off of this assembly method. I have learned first hand that welding aluminum is very expensive and a stronger, cheaper and more repeatable design can be achieved with bolted connections. The stress calculations are more straight forward when you don't have to take into account the weld characteristics.
  • 0

User avatar
Moonbogg
Major General
Major General
 
Posts: 1375
Joined: Mon Oct 13, 2008 10:20 pm
Location: whittier, CA USA
Reputation: 0

Unread postAuthor: Technician1002 » Tue Dec 01, 2009 4:26 am

If you reverse the locations of the barrel and chamber on the valve, it may produce a more rapid opening when the prssure builds past the balance point. A little larger pilot area is a good idea so the piston can move all the way open without too much sudden rise in pilot pressure from compression.

Disclaimer.. Never built a combustion, or hybrid. I may be wrong on this.
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: kenbo0422 » Tue Dec 01, 2009 6:45 am

Technician1002: Your observations are for piston pneumatic. In a combustion, the quick high pressure from the burn is what will force the valve open, as opposed to releasing the pressure from the pilot side. The configuration is correct. But, your suggestion to increase the pilot size is also correct. That valve needs to blast wide open.
  • 0

User avatar
kenbo0422
2nd Lieutenant
2nd Lieutenant
 
Posts: 201
Joined: Mon Oct 06, 2008 7:33 am
Location: East Tennessee
Reputation: 0

Unread postAuthor: frocksie » Tue Dec 01, 2009 5:23 pm

Moonbogg, how would I seal the chamber? O-rings? I am not exactly sure if a bolted construction would work for this particular launcher. Would you mind clarifying?

Technician, I think that this configuration is easier to built and should be fine in terms of performance, but I agree that a larger pilot volume is a good idea. Also, would you suggest using a UMHWPE piston on this gun?
  • 0

“He who controls the present, controls the past. He who controls the past, controls the future.”
-George Orwell
User avatar
frocksie
Sergeant
Sergeant
 
Posts: 91
Joined: Fri Mar 23, 2007 2:05 pm
Location: Maine
Reputation: 0

Unread postAuthor: Moonbogg » Tue Dec 01, 2009 6:14 pm

I was thinking it would need redesigning. If you want to weld then this looks like a good launcher. I was just thinking of ways to make it cheaper. Make sure they have room to work around all the joints.
  • 0

User avatar
Moonbogg
Major General
Major General
 
Posts: 1375
Joined: Mon Oct 13, 2008 10:20 pm
Location: whittier, CA USA
Reputation: 0

Unread postAuthor: frocksie » Tue Dec 01, 2009 7:01 pm

How might you propose to redesign it? I would like to keep the general design, but I am open to some changes.
  • 0

“He who controls the present, controls the past. He who controls the past, controls the future.”
-George Orwell
User avatar
frocksie
Sergeant
Sergeant
 
Posts: 91
Joined: Fri Mar 23, 2007 2:05 pm
Location: Maine
Reputation: 0

Sponsored

Sponsor
 


Return to Hybrid Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], MCRKilljoy, Yahoo [Bot]

Reputation System ©'