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 45 users online :: 4 registered, 0 hidden and 41 guests


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

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

The Team
Administrators
Global Moderators
global_moderators.png CS

Basic design for launcher

Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
Sponsored 
  • Author
    Message

Basic design for launcher

Unread postAuthor: niglch » Sun Aug 05, 2007 10:45 am

I was bored over the last couple days so I decided to model a quick plan for my second cannon. I thought it was a little interesting because of the trigger and handle placement. I'm going for a 1.2:1 C:B ratio with the monster 72" barrel. Any comments are appreciated (like if it's going to blow up, please tell me).

Edit: Blender was used to create the models.
  • 0

Attachments
diagram.png
Diagram
diagram.png (36.73 KiB) Viewed 1009 times
entire.png
Side View
entire.png (10.56 KiB) Viewed 1009 times
front.png
Front view
front.png (27.53 KiB) Viewed 1009 times
back.png
Back view
Last edited by niglch on Sun Aug 05, 2007 11:06 am, edited 1 time in total.

niglch
Staff Sergeant
Staff Sergeant
 
Posts: 116
Joined: Sat Jul 07, 2007 8:14 pm
Reputation: 0

Unread postAuthor: spud yeti » Sun Aug 05, 2007 11:02 am

That looks pretty good. What program do you use?
  • 0

really good quote/phrase here
User avatar
spud yeti
Brigadier General
Brigadier General
 
Posts: 1030
Joined: Tue May 08, 2007 1:41 pm
Location: Cape town south africa
Reputation: 0

Unread postAuthor: iPaintball » Sun Aug 05, 2007 11:05 am

Your rendering looks great! What program did you use?

Anyway, this looks good, but a few things I suggest that should be incorporated in your design are:

1. Add a chamber an to allow more cosistent fueling and firing
2. Wire multiple spark gaps in your chamber
3. If you can, build a propane metering system.

Propane burns much cleaner the aerosol sprays, and you will get mor power and more efficient coumbustion if you do build a meter.

Overall, I really like your design. I hope to see it when it is constructed.
  • 0

Summer Projects:
CO2 tank hybrid: Gotta fix the meter :(
Cane gun: Needs a pilot/fill setup
1.5" piston valve gun: Almost done
User avatar
iPaintball
Colonel
Colonel
 
Posts: 695
Joined: Sun Mar 04, 2007 8:37 pm
Reputation: 0

Unread postAuthor: psycix » Sun Aug 05, 2007 11:22 am

iPaintball wrote:Your rendering looks great! What program did you use?

Anyway, this looks good, but a few things I suggest that should be incorporated in your design are:

1. Add a chamber an to allow more cosistent fueling and firing
2. Wire multiple spark gaps in your chamber
3. If you can, build a propane metering system.

Propane burns much cleaner the aerosol sprays, and you will get mor power and more efficient coumbustion if you do build a meter.

Overall, I really like your design. I hope to see it when it is constructed.


then it wont be a basic design anymore, but an advanced one! ;)
  • 0

User avatar
psycix
Donating Member
Donating Member
 
Posts: 3684
Joined: Mon Jun 25, 2007 7:12 am
Location: The Netherlands
Reputation: 0

Unread postAuthor: SpudBlaster15 » Sun Aug 05, 2007 12:13 pm

With the setup you describe, your ratio will be closer to 0.9:1. It amazes me how so many people cannot even do basic cylindrical volume calculations.

If you want to maintain the same (roughly) chamber volume and increase performance, use a 4" x 10" chamber instead. This will drastically decrease combustion time, and performance will skyrocket.

If you want a 1.2:1 ratio, go with a 4" x 14" chamber.
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Unread postAuthor: niglch » Sun Aug 05, 2007 4:12 pm

SpudBlaster15 wrote:With the setup you describe, your ratio will be closer to 0.9:1. It amazes me how so many people cannot even do basic cylindrical volume calculations.

If you want to maintain the same (roughly) chamber volume and increase performance, use a 4" x 10" chamber instead. This will drastically decrease combustion time, and performance will skyrocket.

If you want a 1.2:1 ratio, go with a 4" x 14" chamber.


I was taking into account the pipe connecting the chamber to the barrel as part of the chamber volume (although I did not list it). I was only being approximate and subtracted some length from the chamber to compensate.
I will take into account what you have said about using a 4" diameter chamber, but I was planning on using dual ignition which may make a 3" chamber perform similar to a 4" chamber. The only other thing I'm wondering about is what I'm going to use for a sight or scope. I know potato guns aren't that accurate, but what the heck, everyone loves scopes.

EDIT: Oops, I happened to be looking at the "smart guess" thing on RatCalc which is where I made my error in chamber volume calculation (I guess the cut piece of chamber pipe will be about 18"). I guess I should have been less lazy and used good old pi*r^2*h.
  • 0


niglch
Staff Sergeant
Staff Sergeant
 
Posts: 116
Joined: Sat Jul 07, 2007 8:14 pm
Reputation: 0

Unread postAuthor: jimmy101 » Sun Aug 05, 2007 4:42 pm

Nice design.

You'll probably want more bracing between the barrel and the chamber, there'll be a heck of a lot of force on the U-bend from chamber to barrel.
  • 0

Image

jimmy101
Lieutenant General
Lieutenant General
 
Posts: 3130
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Country: United States (us)
Reputation: 7

Sponsored

Sponsor
 


Unread postAuthor: niglch » Mon Aug 06, 2007 10:52 am

I was thinking for a bit on this gun and I'm wondering what I would do if a spud was accidentally loaded down the barrel too far and got stuck halfway down the connector. This would probably cause the potato to jam and make the gun unsafe to fire (I'm guessing the chamber would burst if no gas was allowed out). There are plenty of over-under designs like mine though, so how do you prevent this kind of problem?

Thanks
  • 0


niglch
Staff Sergeant
Staff Sergeant
 
Posts: 116
Joined: Sat Jul 07, 2007 8:14 pm
Reputation: 0

Unread postAuthor: pyrogeek » Mon Aug 06, 2007 11:11 am

I use a ramrod long enough to push my spuds or golfballs down to where I want, and that's where they end up. That's good enough for me. Screwing a screw into the end of the barrel through the fitting would act as a stop though, if you want something more definitive.
  • 0

I'm weird, I know it, you don't need to tell me.

pyrogeek
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 457
Joined: Sat May 13, 2006 7:43 pm
Location: moline Illinios
Reputation: 0

Unread postAuthor: SpudBlaster15 » Mon Aug 06, 2007 11:43 am

You can also breech load to prevent this problem.
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Unread postAuthor: jimmy101 » Mon Aug 06, 2007 12:23 pm

niglch wrote:I was thinking for a bit on this gun and I'm wondering what I would do if a spud was accidentally loaded down the barrel too far and got stuck halfway down the connector. This would probably cause the potato to jam and make the gun unsafe to fire (I'm guessing the chamber would burst if no gas was allowed out). There are plenty of over-under designs like mine though, so how do you prevent this kind of problem?

Thanks

I don't hink it is possible to jam a spud tightly enough to cause a problem. The spud will start to move, perhaps by fragmenting, when the pressure gets high enough. So I wouldn't worry about it too much.
  • 0

Image

jimmy101
Lieutenant General
Lieutenant General
 
Posts: 3130
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Country: United States (us)
Reputation: 7

Unread postAuthor: sandman » Mon Aug 06, 2007 3:18 pm

as long as you use pressure rated parts i dont see this being a problem, the fittings should be able to take the pressrue
  • 0


sandman
Colonel
Colonel
 
Posts: 672
Joined: Thu Mar 15, 2007 6:59 pm
Reputation: 0

Unread postAuthor: niglch » Mon Aug 06, 2007 9:33 pm

Agh, ok I was just thinking for a while about how I should go about that whole crazy BBQ trigger system I came up with. As already stated, the chamber will need to be sufficiently braced to the barrel with the design I have. Admittedly, I'm still quite a n00b and I'm not sure what to use to secure the trigger part between the barrel and chamber and have it play the double role of serving as a good bracing, too.

Sorry I'm asking so many questions but I've searched the forums a lot and haven't found much. At least I'm trying to keep my noobiness confined to this one topic :D

note: i'm now planning on using a shorter 4" chamber instead of a long 3" one.

Thanks again!
  • 0


niglch
Staff Sergeant
Staff Sergeant
 
Posts: 116
Joined: Sat Jul 07, 2007 8:14 pm
Reputation: 0

Unread postAuthor: Modderxtrordanare » Tue Aug 07, 2007 2:30 am

niglch wrote:Agh, ok I was just thinking for a while about how I should go about that whole crazy BBQ trigger system I came up with. As already stated, the chamber will need to be sufficiently braced to the barrel with the design I have. Admittedly, I'm still quite a n00b and I'm not sure what to use to secure the trigger part between the barrel and chamber and have it play the double role of serving as a good bracing, too.

Sorry I'm asking so many questions but I've searched the forums a lot and haven't found much. At least I'm trying to keep my noobiness confined to this one topic :D

note: i'm now planning on using a shorter 4" chamber instead of a long 3" one.

Thanks again!


Take two pipe saddles (or tees you saw in half) and connect them (you'll need reducing bushings in them, since the barrel and chamber are different sizes) and use hose clamps to hold them to the barrel and chamber. That will be a sufficient brace to support the barrel and chamber. You could then attach your bbq ignitor to that and have one of your handles done. :)
  • 0

Spudding since '05. Proud waster of plumbing and plumbing accessories.

-Wiki
-How-To: Modding a Sprinkler Valve
User avatar
Modderxtrordanare
Donating Member
Donating Member
 
Posts: 686
Joined: Mon Nov 20, 2006 1:22 pm
Location: Texas
Reputation: 0

Unread postAuthor: Redcoat » Tue Aug 07, 2007 4:57 am

thats a good clean design and would would work.

Post it when your done.If you are building it at all.

Happy Spuddin'
  • 0

Poo.
User avatar
Redcoat
Brigadier General
Brigadier General
 
Posts: 836
Joined: Tue Feb 13, 2007 1:07 am
Location: Sydney ,Australia
Reputation: 0

Next

Return to Combustion Cannon Discussion

Who is online

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

Reputation System ©'