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-   -   Optimizing Air Cannon Range (http://www.chiefdelphi.com/forums/showthread.php?t=49224)

Tytus Gerrish 02-10-2006 01:10

Re: Optimizing Air Cannon Range
 
I have found in my vast experience and long history of projectile launchers. the more kenetic energy you can put into a mass before it leaves your grip the faster and further it will go. i have completely given up on Compressed air and almost only use CO2. its cheap, available anywhere with paintball. and as long as there is Liquid CO2 present in the tank the gas maintains a pressure around 1100 PSI. the more pressure you have the smaller you can make your device and the more energy you can put into your projectile's mass. i have stop referring to my CO2 potato launchers as launchers and rather as potato sniper rifles. the vegetables come out of the barrel so quickly that at a range of about 30 feet potato's atomize upon impact of a hard surface. If you relay want to throw a t-shirt up into a crowd with compressed air alone you are going to need allot and I mean allot of it! and a very long barrel to transfer that energy to a shirt. if you want a device you can hold in your hand and shoot out into a crowd an long distances of 150 feet and beyond you simply need more pressure. But please be carefull and remember how Maude Flanders Died.

Gdeaver 02-10-2006 08:24

Re: Optimizing Air Cannon Range
 
A sabot casing will greatly increase performance. There's allot on the web for water balloons. Co2 is much better than air, however it's high pressure and needs allot more care. Co2 has it's limits when when large volumes are released. The drop in pressure limits the flash rate. That's why nitrogen has taken over for serious paint ballers.

Tytus Gerrish 02-10-2006 09:05

Re: Optimizing Air Cannon Range
 
Quote:

Originally Posted by Gdeaver
A sabot casing will greatly increase performance. There's allot on the web for water balloons. Co2 is much better than air, however it's high pressure and needs allot more care. Co2 has it's limits when when large volumes are released. The drop in pressure limits the flash rate. That's why nitrogen has taken over for serious paint ballers.

i agree a sabot case would allow you to increace the surface area that the compressed gas pushes on witch will transfer energy to it more quickley. however I don't think there's much sabot casing you can do with a rolled t-shirt. witch by itself can be used as a sabot casr for another object.

Andrew Schuetze 02-10-2006 13:26

Re: Optimizing Air Cannon Range
 
We performed the test of a manual ball valve today during class. We doubled our range and added to the altitude achieved. The diaphragm based sprinkler valve opens too slowly and limits air flow as suspected. To make this a remote device on the robot we'll use a short throw pneumatic cylinder activated by a festo solenoid. I've got video of the test but no place to upload at the moment that the school filters will allow me access. :ahh:

Quote:

Originally Posted by Andrew Schuetze
Thinking along the same lines, I traded in a Rainbird valve this evening for a 1 inch ball valve with a three inch lever handle, rotates 90 degrees.

The plan is to test this manually as a comparison to the sprinkler valve and if it yields a better performance, the we will have to build in a festo solenoid activated pneumatic piston to open and close this valve remotely.

Performance is limited by a slow opening valve. We discovered this when we added a second valve to our set up and were testing the timing of the two opening together. We decided the mechanical operation of the pressure diaphram was not going to yeild consistant and tunable results for a simultaneous opening.

APS


Donut 06-10-2006 01:36

Re: Optimizing Air Cannon Range
 
Finally got our cannon mounted, finished, and tested today. ~40 feet at 80 psi. We hope to extend the range later, but it will be more than good enough for Homecoming tommorow.

John Gutmann 16-10-2006 00:51

Re: Optimizing Air Cannon Range
 
It may or may not be relavent now, but if you use CO2 it will be up around 800 psi.

EDIT: oops didn't see the second page of the thread.

And aren't paintball gun tanks at around 800 psi?

Tytus Gerrish 16-10-2006 10:02

Re: Optimizing Air Cannon Range
 
Quote:

Originally Posted by sparksandtabs
It may or may not be relavent now, but if you use CO2 it will be up around 800 psi.

EDIT: oops didn't see the second page of the thread.

And aren't paintball gun tanks at around 800 psi?

yes, you're right. i have to correct myself from before.

wikipedia: "at room temperature it becomes a liquid at a pressure of 60 bar. A tank of liquid carbon dioxide provides a constant 60 bar pressure until the tank is close to being empty."

60 bar = 870.226 psi

Tatsu 23-10-2006 12:35

Re: Optimizing Air Cannon Range
 
We just built an air cannon to fire confetti.. with a delrin projectile we got something like 80-90 ft of range..

I agree that the biggest problem is the valve.. We got a manual-open spinkler valve which seems to work better than the solenoids (which seems to "honk" as others have said) to be honest, the best solution is to use a large valve but those are hard to find, and diaphram types seem to open faster (from what I've read)

we'll be improving our cannons (we have 2) so I'll keep posting.

Andrew Schuetze 26-10-2006 16:17

Re: Optimizing Air Cannon Range
 
Quote:

Originally Posted by Tatsu
I agree that the biggest problem is the valve.

Our solution was to use a manual ball valve. This is mechanically operated via a pnuematic piston. Take a look here.
http://www.chiefdelphi.com/media/photos/25728

:D

Andrew Schuetze 21-05-2007 17:52

Re: Optimizing Air Cannon Range
 
Hope to have the robot robot reprogrammed during school tommorrow but this valve just came in today. The local area Parker sales representative was willing to help our our team so that we can take our tee shirt cannon modified robot to a minor league baseball game.:yikes:
Quote:

I will be glad to donate an N series valve to your project.

The part number I come up with is a N3157104545. This is a 2 way NC
(Normally non passing) 12VDC coil with 1" ports.
I plumbed it in this afternoon and a manual test sounds impressive with an immediate blast of air at the full 100 psi. Will post some video as soon as the programming is done and we can capture the new and improved version of the cannon in action.

APS

Molten 23-05-2007 20:59

Re: Optimizing Air Cannon Range
 
Thanks to all of you on this thread and those who helped inspire it. Team 1766 is now looking into making a shirt cannon and then shooting it at sports events. We are hoping to use this as some sort of fund raiser for the team and hopefully even get the team a little attention from the public.

cbale2000 23-05-2007 22:56

Re: Optimizing Air Cannon Range
 
Quote:

Originally Posted by Matt H. (Post 526080)
Thank you all very much for your advice. Tonight I tested the cannon with 80PSI and shot a well rolled and rubber banded tee-shirt lubricated with talcum powder 25 yards. This is a significant improvement over last nights performance it is still lacking.

I hope you don't plan on using talcum for any use at an actual event... for the sake of any asthmatics in the crowd.

And Talc itself has some heath problems as well, take a look at this bit from Wikipedia:

Quote:

Originally Posted by Wikipedia- Talc
Several studies have established preliminary links between talc and pulmonary issues, lung cancer, skin cancer and ovarian cancer. This is a major concern considering talc's widespread commercial and household use. However, no conclusive study has yet been made to determine either the toxicity and/or carcinogenic nature of talc and the long history of safe use suggests that these concerns are unfounded. The U.S. Food and Drug Administration (FDA) considers non-asbestiform talc, that is talc which does not contain potentially carcinogenic asbestiform amphibole fibers, to be Generally recognized as safe (GRAS) for use in cosmetics. In 1993, a US National Toxicology Program report found that cosmetic grade talc caused tumours in animals, even though it contained no asbestos-like fibres. Scientists have been aware of the toxicity of talc since the late 1960s, and in 1971 researchers found particles of talc embedded in 75 percent of the ovarian tumors studied.


I know, not really related to the subject of Air Cannons, but I thought it was important to point out anyways, especially seeing as my mother almost died from an asthma attack after someone thought it would be a neat idea to put talcum powder in her sleeping bag on a camping trip she went on once. Just wouldn't want anyone grabbing a T-shirt thats been launched at them, only to put it on and stop breathing. ;)

Travis Hoffman 24-05-2007 13:43

Re: Optimizing Air Cannon Range
 
Quote:

Originally Posted by cbale2000 (Post 628919)
I hope you don't plan on using talcum for any use at an actual event... for the sake of any asthmatics in the crowd.

Use cornstarch based powder instead.

dtengineering 24-05-2007 18:01

Re: Optimizing Air Cannon Range
 
We had luck using water as a lubricant in the water balloon cannon we built several years ago. It might not be ideal for a t-shirt cannon unless the t-shirt is wrapped in saran wrap or something similar, but it does enhance the cool condensation cloud you get misting out of the barrel afterwards.

Jason

EricRobodox 26-05-2007 22:33

Re: Optimizing Air Cannon Range
 
well, we made one, just did not get the valve working the way we wanted. Pressure was ok, just the valve we used didnt fire fast enough. We scrapped it.
Folding the shirt was technique though. Fold like a normal t-shirt going into your drawer; thats the both sleeves in and then fold over so colar is showing on one side. Then after this, fold in half so that the colar is not showig at all, as in it folded the colar in half and its on the inside of the fold. Take that and roll it, it should be perfect for a 3" diameter pvc tube.


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