Go to Post There is no MILSPEC standard for pool noodles. - Rick TYler [more]
Home
Go Back   Chief Delphi > Technical > Pneumatics
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Closed Thread
 
Thread Tools Rating: Thread Rating: 3 votes, 3.67 average. Display Modes
  #1   Spotlight this post!  
Unread 30-09-2006, 00:23
Matt H. Matt H. is offline
Long Distance Mentor
FRC #1726 (N.E.R.D.S.)
Team Role: Alumni
 
Join Date: May 2006
Rookie Year: 2007
Location: Sierra Vista, AZ
Posts: 238
Matt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond repute
Optimizing Air Cannon Range

At around 8:00 tonight my team (1726) tested a pneumatic tee-shirt cannon. We were overjoyed that the tee-shirt was launched, but found distance to be lacking. I am wondering if some of the members more experienced with tee-shirt cannons might be able to give us some advice on how to optimize our performance. Advice on how to fold the tee-shirts as well as any optimizations in our pneumatics systems would be accepted gratefully; we used the following pneumatics system.

KOP Compressor-standard tubing-7gal steel air tank-1/2in brass fitting-10' 1" braided nylon tubing-inline rain bird valve-2in fitting-3in cannon.

When the cannon fires it makes a sound resembling a large air horn.

On our test shot we fired at a 45 degree angle and simply stuffed the tee-shirt into the cannon barrel. We are unsure of the PSI because much of our stored air had been wasted in a previous shot and no one bothered to check the valve; however it is estimated to have been between 40-50.

Thanks in Advance for the help.
  #2   Spotlight this post!  
Unread 30-09-2006, 12:31
Cody Carey's Avatar
Cody Carey Cody Carey is offline
,':-)
AKA: C. Carey
FRC #0306 (CRT)
Team Role: Alumni
 
Join Date: Feb 2005
Rookie Year: 2004
Location: Corry, PA
Posts: 1,137
Cody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond repute
Send a message via AIM to Cody Carey Send a message via Yahoo to Cody Carey
Re: Optimizing Air Cannon Range

OK, we get our farthest shots when we shoot with the arm elevated to about 40*. 50psi does mid-range shots with footballs and short range shots with the t-shirts. In order to get our t-shirts to travel mid to long range when we shoot them, we have to have at least 80 psi in our cannon, and even up to 110psi to get them to really go.
One thing you have to remember, though, is that when you are at football games, you are shooting into a sea of people, and because of that, you generally want to have your angle be more than 45-50*, so everyone has more time to react, even shooting in large arcs, we have still managed to hit a couple of people in the head. Another good Idea is to have the announcer tell the crowd when you are going to shoot, so they are all looking your way and can't be caught off guard, we do this when we are shooting Shirts, but a simple honk of our horn does well while we are shooting foam footballs and nobody really stands any chance at getting hurt.


We fold our tee-shirts by folding them in half height wise, and then rolling them up tightly lengthwise, we also wrap the shirts in plastic bags with a bit of tape on the outside so they don't unroll in flight, because if we let them unroll, they don't end up flying more than 10 feet.
__________________
  #3   Spotlight this post!  
Unread 30-09-2006, 12:41
Doug G's Avatar
Doug G Doug G is offline
Coach / Teacher
FRC #0701 (Robovikes)
Team Role: Coach
 
Join Date: Dec 2002
Rookie Year: 2001
Location: Fairfield, CA
Posts: 879
Doug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond repute
Re: Optimizing Air Cannon Range

It sounds like a similar setup to ours. We just make sure that all tubing, pipe diam's are at least 3/4" or more. We operate ours at about 80-90 psi and we get 3 or 4 good shots off with it. However we haven't launched any t-shirts with it yet, just foam soccer balls and footballs. We get 50 to 100 feet reliably. I highly suggest placing a pressure indicator on it so you can better tune your shots. We hooked up the old analog pressure sensor (TI) that was in the kit a few years ago (2004 ?) and hooked it into the analog port of the robot controller. Next we'll modify the program so that the operator interface will indicate with the Feedback LEDs if it's too low of a pressure or something along those lines.

Good luck
__________________
Work Hard, Have Fun, Make a Difference!

  #4   Spotlight this post!  
Unread 30-09-2006, 12:48
Cody Carey's Avatar
Cody Carey Cody Carey is offline
,':-)
AKA: C. Carey
FRC #0306 (CRT)
Team Role: Alumni
 
Join Date: Feb 2005
Rookie Year: 2004
Location: Corry, PA
Posts: 1,137
Cody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond repute
Send a message via AIM to Cody Carey Send a message via Yahoo to Cody Carey
Re: Optimizing Air Cannon Range

Quote:
Originally Posted by Doug G
I highly suggest placing a pressure indicator on it so you can better tune your shots. We hooked up the old analog pressure sensor (TI) that was in the kit a few years ago (2004 ?) and hooked it into the analog port of the robot controller. Next we'll modify the program so that the operator interface will indicate with the Feedback LEDs if it's too low of a pressure or something along those lines.

Good luck

We did the same thing, except we get a pressure readout in numbers on the OI, It really helps us tune the shots. We also have it set up so that a pot controls how much pressure is put into the tank. When we set the pot to what we made 60psi, it will charge to 60, and regardless of any minor leaks will stay at 60 by sporadically charging when the pressure drops.
__________________
  #5   Spotlight this post!  
Unread 30-09-2006, 14:31
GMKlenklen's Avatar
GMKlenklen GMKlenklen is offline
The "Masonater"
AKA: George Mason Klenklen
FRC #2167 (MASMabots)
Team Role: Leadership
 
Join Date: Sep 2006
Rookie Year: 2006
Location: Maryville, MO
Posts: 120
GMKlenklen is a name known to allGMKlenklen is a name known to allGMKlenklen is a name known to allGMKlenklen is a name known to allGMKlenklen is a name known to allGMKlenklen is a name known to all
Send a message via AIM to GMKlenklen Send a message via MSN to GMKlenklen Send a message via Yahoo to GMKlenklen
Re: Optimizing Air Cannon Range

has anyone tried shooting stuff with a wheel? like lots of teams did for the '06 game. I think that would be a little more efficient than the pneumatic gun, plus one would make it self-loading!
__________________
Thank you,
formerGrand Master Klenklen
-of the MASMabots-
  #6   Spotlight this post!  
Unread 30-09-2006, 16:41
Kevin Sevcik's Avatar
Kevin Sevcik Kevin Sevcik is offline
(Insert witty comment here)
FRC #0057 (The Leopards)
Team Role: Mentor
 
Join Date: Jun 2001
Rookie Year: 1998
Location: Houston, Texas
Posts: 3,701
Kevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond repute
Send a message via AIM to Kevin Sevcik Send a message via Yahoo to Kevin Sevcik
Re: Optimizing Air Cannon Range

Your cannon is honking when you fire it? If so, I suspect your fancy rainbird valve isn't working as well as you think. I'm actually surprised it's even sealing particulary well, since the one I used for my ping-pong ball cannon refused to seal with air without heavy modifications.

At any rate, you probably need to make the whole air system more efficient. 10' of 1" tubing is going to restrict a lot of your air flow. Chances are that your t-shirt will be mostly down your barrel before any of the air from te storage tank gets to the valve. Secondly, your valve needs to open rapidly and completely. Right now, it sounds like it's mostly opening, and the are rusing past the membrane inside is making it vibrate and disrupt the airflow. You can either switch to a butterfly valve actuated with a pneumatic piston, or modify your solenoid valve. I sealed up the hole in the membrane, and pressurized the top chamber seperately. I also put a spring inside the valve to push the membrane up and out of the way more completely.

That's all assuming you want to improve your design. Your other option is to simply throw more PSI at everything, and hope nothing explodes and injures you. Seriously. Your tubing and valve there are only meant to work with water, which is fairly incompressible. Filling up that 1" tube with compressed air is an accident waiting to happen. Especially since it sounds like the only pressure control in your system is the 120 psi relief valve on the compressor.

At any rate, efficiency is more fun. My ping-pong cannon was about 1' long, total. The air chamber was 4" of 1.5" PVC, and the barrel was about 3" long. It still launched balls farther than the huge monstrosities other teams built with 2 foot long barrels and 2'x3" air chambers. Unfortunately, the goal was accuracy, and that's a bit hard with a cannon that shoots things 30' on 20 psi.
__________________
The difficult we do today; the impossible we do tomorrow. Miracles by appointment only.

Lone Star Regional Troubleshooter
  #7   Spotlight this post!  
Unread 30-09-2006, 16:54
Andrew Blair's Avatar
Andrew Blair Andrew Blair is offline
SAE Formula is FIRST with Gasoline.
FRC #0306 (CRT)
Team Role: Alumni
 
Join Date: Feb 2005
Rookie Year: 2004
Location: Corry
Posts: 1,193
Andrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond repute
Send a message via AIM to Andrew Blair Send a message via Yahoo to Andrew Blair
Re: Optimizing Air Cannon Range

Three things: like Cody said, rolling the t-shirt and taping it will significantly improve your range. Secondly, the valve has an ID of like 3/4", so your tank with the 1/2" fitting may be a bottleneck, but thirdly, t-shirts are not really the best projectiles for perfomance. If you really want to see capability, find a ball that more or less perfectly fit's the ID of your barrel. Shirts, unless rolled in a very tight, almost bullet like shape with a perfect mate to your barrel, will not fly extremely well, no matter what you do.
__________________
Reading makes a full man, conference a ready man, and writing an exact man.
-Sir Francis Bacon

"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius -- and a lot of courage -- to move in the opposite direction."
-Albert Einstein
  #8   Spotlight this post!  
Unread 30-09-2006, 21:54
Alex698's Avatar
Alex698 Alex698 is offline
Sparky
FRC #2449 (Out of Orbit Robotics)
Team Role: Mentor
 
Join Date: Jan 2005
Rookie Year: 2005
Location: Arizona
Posts: 114
Alex698 is a jewel in the roughAlex698 is a jewel in the roughAlex698 is a jewel in the rough
Send a message via AIM to Alex698
Re: Optimizing Air Cannon Range

Quote:
Originally Posted by GMKlenklen
has anyone tried shooting stuff with a wheel? like lots of teams did for the '06 game. I think that would be a little more efficient than the pneumatic gun, plus one would make it self-loading!
I'm with Team 698. We shot shirts using a modified assembly from the 2006 game. I should have a video on our website soon. (www.hamiltonrobotics.org)
__________________
Eat, Sleep, Build Robots
  #9   Spotlight this post!  
Unread 30-09-2006, 23:42
Matt H. Matt H. is offline
Long Distance Mentor
FRC #1726 (N.E.R.D.S.)
Team Role: Alumni
 
Join Date: May 2006
Rookie Year: 2007
Location: Sierra Vista, AZ
Posts: 238
Matt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond repute
Re: Optimizing Air Cannon Range

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'm not sure why the tubing would restrict our airflow. The opening from the tank to the tubing is 1/2 opening and I don't believe that can be modified with out significant structural changes to the tank itself. Since the tubing is a large diameter than this opening the tubing should not at all restrict the airflow no matter how long.

I will however look into a butterfly valve. I am slightly worried about time however because the robot must be finished before 10/20 which is our homecoming game.

Also does anyone know at a glance how fast could a butterfly valve open when actuated with a KOP pneumatic system?

Also should be make a chamber of say 5" steel piping directly attached to the valve (which is directly attached to the cannon) to improve airflow; that is definitely an option. I believe (however I am often wrong) that because our cannon is 3 1/2' long (3" diameter) a chamber of 5" diameter piping 1'4" long would allow for complete expansion into the barrel. Would this have any significant effect on our efficiency?

Thanks again, sorry for having so many questions.
  #10   Spotlight this post!  
Unread 30-09-2006, 23:55
Matt H. Matt H. is offline
Long Distance Mentor
FRC #1726 (N.E.R.D.S.)
Team Role: Alumni
 
Join Date: May 2006
Rookie Year: 2007
Location: Sierra Vista, AZ
Posts: 238
Matt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond repute
Re: Optimizing Air Cannon Range

In addition to the questions above; Does anyone know a reliable supplier of butterfly valves?
  #11   Spotlight this post!  
Unread 01-10-2006, 03:04
Cody Carey's Avatar
Cody Carey Cody Carey is offline
,':-)
AKA: C. Carey
FRC #0306 (CRT)
Team Role: Alumni
 
Join Date: Feb 2005
Rookie Year: 2004
Location: Corry, PA
Posts: 1,137
Cody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond reputeCody Carey has a reputation beyond repute
Send a message via AIM to Cody Carey Send a message via Yahoo to Cody Carey
Re: Optimizing Air Cannon Range

Your valve is probably not that big of a problem right now, and our robot makes the horn sound as well, but functions just fine... What will definitely improve your performance would be finding a tank with an opening the diameter of the pipe you are using, as that is the only (major) bottleneck in your system right now.



(Just included the gif for interest's sake )
__________________
  #12   Spotlight this post!  
Unread 01-10-2006, 12:45
Donut Donut is offline
The Arizona Mentor
AKA: Andrew
FRC #2662 (RoboKrew)
Team Role: Engineer
 
Join Date: Mar 2005
Rookie Year: 2004
Location: Goodyear, AZ
Posts: 1,302
Donut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond repute
Re: Optimizing Air Cannon Range

If you're using a tank with a 1/2" hole, why not move most of your system down to about that?

We decided to go with a 3/4" Rain Bird Valve and 5/8" ID tubing since we knew the tank was a bottleneck. The advantage is we now have a higher psi rating on them all, and I'm not so afraid to take it up to 120 when the time comes anymore.

Of course we're actually testing it today, we'll see how it goes.
__________________
FRC Team 498 (Peoria, AZ), Student: 2004 - 2007
FRC Team 498 (Peoria, AZ), Mentor: 2008 - 2011
FRC Team 167 (Iowa City, IA), Mentor: 2012 - 2014
FRC Team 2662 (Tolleson, AZ), Mentor: 2014 - Present
  #13   Spotlight this post!  
Unread 01-10-2006, 21:39
Andy B's Avatar
Andy B Andy B is offline
College Student, Mentor
FRC #1259 (Paradigm Shift)
Team Role: Mentor
 
Join Date: Jan 2005
Rookie Year: 2004
Location: Pewaukee, WI
Posts: 33
Andy B will become famous soon enough
Send a message via AIM to Andy B
Re: Optimizing Air Cannon Range

There are several things here:

*You want your air to move as easily as possible = use the biggest valve you can, and the biggest pipe/tubbing from the chamber to the valve to the barrel. In a perfect world, if you were using a 2" barrel, a 2" valve and 2" pipe from the chamber to the valve would be great. That may not be possible though.

So, your 10 feet of 1" tubing is costing you a lot of power.

*You want to release all of your air at once+ get the fasting acting valve you can find. A good solution is a sprinkler valve. These are electrically controlled, so you could use them with the FRC robot components.

In a perfect world, you might use a large chamber, have a pipe come out of one end the same size as your valve, have that pipe turn 180 degrees, go into the valve which then goes right into the barrel.

Really, you want as little extra pipe as possible.

These t-shirt launchers are a lot like pneumatic potato guns. I suggest you explore this site for some quality information:

This is a god example of an efficient gun that you might consider.

http://spudtech.com/detail.asp?id=52

You may want to peruse the rest of the site for more information, especially the "links" tab.

If you want more information about optimal chamber to barrel size ratios, PM me, there is much more info out there.
__________________
Andy B: College Student, Mentor
Paradigm Shift, 1259 http://www.team1259.org
2004 Midwest Regional: Team Spirit Award Winner, Highest Seeded Rookie Team Award Winner, 4th Seed, 7-1-0 Record , Lost in Quarter Finals
2005 Midwest Regional: Imagery Award Winners, 16th Seed, 5-5-0 Record, Unpicked
2005 Championships, Newton Division: 5th seed, 6-1-0 Record, Advanced to semifinals
2006 Wisconsin Regional: Judges Award, 23th seed, 5-7-0 Record, Unpicked
2007 Wisconsin Regional: 33rd seed, 3-4-1 Record, Lost in Quarterfinals
Closed Thread


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
potato cannon northendchopper Chit-Chat 14 16-12-2009 12:19
pic: Toltech Air Cannon Prototype Andrew Schuetze Extra Discussion 2 29-05-2007 15:29
FIRST air cannon robots PVC?? Andrew Schuetze Pneumatics 40 03-01-2007 15:16
Air Cannon Michael223 Technical Discussion 13 14-06-2006 10:23
Are we allowed to use a Bimba air-to-air booster? Alex Minot Pneumatics 1 20-02-2005 22:32


All times are GMT -5. The time now is 06:23.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi