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 77 users online :: 3 registered, 1 hidden and 73 guests


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

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

The Team
Administrators
Global Moderators
global_moderators.png CS

Plans / designs for a 75mm diameter can firing gun / cannon

A place to ask general spud cannon related questions.
Sponsored 
  • Author
    Message

Plans / designs for a 75mm diameter can firing gun / cannon

Unread postAuthor: bat666 » Thu Jun 01, 2006 2:01 pm

Hi,

I've been given the task of building a pneumatic gun / cannon capable of firing a 75mm diameter tin (weight roughly 450g) and hitting a target with some degree of accuracy 50m away. The pressure will be limited to 147 psi.

Rather than trying to re-invent the wheel, I was wondering if anyone has built something similar and is willing to share their designs, successes and pitfalls to help me on the way. e.g. what length of barrel to use, capacity of air tank reservoir required ?? etc..

Any information would be greatly received.

Cheers,

Andy
  • 0


bat666
Private
Private
 
Posts: 2
Joined: Thu Jun 01, 2006 1:43 pm
Reputation: 0

Unread postAuthor: Benny » Fri Jun 02, 2006 12:44 am

wiki.
  • 0


Benny
Brigadier General
Brigadier General
 
Posts: 844
Joined: Wed Apr 19, 2006 8:21 pm
Location: Tasmania, Australia.
Reputation: 0

Unread postAuthor: rna_duelers » Fri Jun 02, 2006 5:47 am

People dont like giving away plans for things make your own deisgn.But i'd say a sprinkler valve wouldnt go 2 bad for only 50m away.
  • 0

Image
User avatar
rna_duelers
Major General
Major General
 
Posts: 1740
Joined: Mon Sep 26, 2005 7:07 am
Location: G-land Australia
Country: Australia (au)
Reputation: 1

Unread postAuthor: jrrdw » Fri Jun 02, 2006 6:37 am

Wiki stands for Spud Wiki, and there you can find basicly all the info your looking for. There is also the GGDT= Gas Gun Design Tool, it is a program that gives you basic avereges on volicity/distances of the projectile your useing, but you have to know the sizes of your cannon to run the program, and have some good computer skills to install it.

A better discription of the GGDT: http://www.spudfiles.com/spud_wiki/inde ... esign_Tool

Here is were to get it: http://www.thehalls-in-bfe.com/GGDT/
  • 0

When life gives you lemons...throw them back they suck!
User avatar
jrrdw
Donating Moderator
Donating Moderator
 
Posts: 6538
Joined: Wed Nov 16, 2005 5:11 pm
Location: Maryland
Country: United States (us)
Reputation: 25

Unread postAuthor: The Haymaker » Fri Jun 02, 2006 6:50 am

You can do it pretty simply with a hand operated valve. I'm doing that with a 2" barrel, 3" rezzies, and only a 1.5" brass ball valve. The trick to accuracy at distance is barrel length (I'm running 17'!) and proper projectile weighting.

I'm having temenodous luck with 2" aluminum caulking tubes weighted out with 2" of concrete in the tip. These puppies fly like an arrow, are almost unlimited in supply, and very easy to make. Key is to use the aluminum ones. Cardboard ones tumble almost every time, plastic usually flutters before settling on track. Either greatly reduces range/ accuracy. At 700' I'm hitting a target only 4' wide and 8' tall. When I get around to using screwdrives to aim, instead of doing it freehand, I expect things to get much better. It's VERY hard to judges elevation when you're dealing with slightly differing weights and air pressures each shot.

I have no plans, though I know how to share and have posted vids at:
http://www.xr650r.us/video
and
http://www.xr650r.us/cannon

Unfortunately I have had no time to make newer videos, so these older ones don't show the current long barreled setup.

These things are so forgiving that there's really just no need for plans. I built one from my head after perusing the net, and then modified it through stages up to this point. Next in line is 4" steel rezzies and a piston valve. Then I start on the 3" barreled monster!

Just keep in mind, you need air (rezzie) enough to supply air until the projectile has left the barrel, barrel enough to allow the projectile to reach max acceleration before leaving it, and large enough piping/valve to supply max air flow. The last element can be eliminated by goingto a coaxial style valve, which I have planned in the future.

For instance, I ended up with a 17' barrel, because at 10' I was getting a ver loud "pop" and whoosh of escaping air when the projectile cleared the barrel. After going to 17', which greatly increased range, I get more of a "crack" report with much less whoosh. To me, translated, means the projectile has come closer to the speed of escaping air, lowering the pressures behind it when it escapes the barrel.

Phew, my fingers are tired!

E

E
  • 0

The Haymaker
Corporal
Corporal
 
Posts: 74
Joined: Thu Sep 22, 2005 4:52 am
Location: Cowtipping, Maine
Reputation: 0

Unread postAuthor: sgort87 » Fri Jun 02, 2006 4:15 pm

You know what, I can see why people asking for plans can piss people off but cases like this where he politely asks and supplies us with a specific goal there is no reason to turn him away and tell him to "go do some research". He probably has some sort of deadline as well. So how about we suggest a few things to him like Haymaker eh?

I'd suggest a pneumatic cannon using a sprinkler valve because they will be consistent. By that I mean it will always react the same with each shot and you can carefully line it up with the target. Combustions have a chance to mix poorly etc.

If you do not have access to a compressor or bike pump then Say so and we will help you with a combustion.

Minions, educate this gentelman on the topic of modified sprinkler valved basic pneumatic launchers. I have other threads to post in...
  • 0

<a href="http://www.launchpotatoes.com"><img src="http://www.launchpotatoes.com/images/uploads/logo2.PNG"></a>
http://www.LaunchPotatoes.com
User avatar
sgort87
Donating Member
Donating Member
 
Posts: 1038
Joined: Sun Sep 18, 2005 10:32 am
Location: Lockport, Illinois
Country: United States (us)
Reputation: 1

Unread postAuthor: bat666 » Mon Jun 05, 2006 4:20 pm

Cheers,

Thanks for all the info; you've certainly given me food for thought.

I forgot to mention that the first part of the task is to build a tracked vehicle to carry the gun on and so we'll be using some form of engine driven compressor to feed the gun; combustion is not permitted.

The gun / cannon has to be detachable, ideally have the ability to rotate and the overall vehicle length is only going to be roughly 3-4m long. Therefore to try and keep the gun in perspective with the overall size and style of the vehicle I was trying to achieve a balance between the length of the barrel needed and the accuracy required (i.e the shorter the barrel the better - if that makes any sense!).

I've looked at the use of sprinkler valves and hopefully a work colleague of mine will bring a couple back from the USA when they return from holiday. If not, I'll probably have to opt for using a ball valve as sprinkler valves seem to be either an extortionate price or very hard to come by in the UK.

I've also tried out a few of the programs you've recommended to calculate the barrel length required and noticed that the capacity of the reservoirs makes quite an impact on the calculations. Is there a minimum / maximum size of air reservoir you would recommend? For example, I'm considering using either 1 or 2 4" tanks (if I manage to get the sprinkler valves). Any suggestions on the size the tanks should be??

Thanks once again,

Andy

PS - very impressed with the videos!
  • 0


bat666
Private
Private
 
Posts: 2
Joined: Thu Jun 01, 2006 1:43 pm
Reputation: 0

Sponsored

Sponsor
 


Return to General Spud Cannon Related

Who is online

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

Reputation System ©'