Page 41 of 58

Re: Air Trajectory B/C

Posted: February 24th, 2015, 5:40 pm
by bernard
ImNotSmart wrote:I think mine's about 0.75 meters when fully extended. How wide is your pump? I think that my pump may not be producing enough air pressure because it is not wide enough. I dont think I feel any air leaking, so the width may be the problem. Howyou change how far your device fires? What "setting"you use to have it launch 8 meters? Also, sorry if this is too much to ask, but I'm still not sure if I understand how your trigger works. Could you possibly upload a picture of the trigger on your device? Thanks for everything! You've given me a lot more insight on the project!
Try using a shorter barrel to get more distance. If your pump is shorter it is compressing less air into the barrel so you want a shorter barrel to get a er increase in pressure. I vary the angle of my barrel to hit different distances. My device originally didn't launch to 8 meters but with adjustments in how tightly the ball fit in the barrel, it started launching 8 meters. I don't have my device on me right now, so I'll take a picture of it when I get home.

Re: Air Trajectory B/C

Posted: February 25th, 2015, 12:52 am
by bernard
bernard wrote:
ImNotSmart wrote:I think mine's about 0.75 meters when fully extended. How wide is your pump? I think that my pump may not be producing enough air pressure because it is not wide enough. I dont think I feel any air leaking, so the width may be the problem. Howyou change how far your device fires? What "setting"you use to have it launch 8 meters? Also, sorry if this is too much to ask, but I'm still not sure if I understand how your trigger works. Could you possibly upload a picture of the trigger on your device? Thanks for everything! You've given me a lot more insight on the project!
Try using a shorter barrel to get more distance. If your pump is shorter it is compressing less air into the barrel so you want a shorter barrel to get a er increase in pressure. I vary the angle of my barrel to hit different distances. My device originally didn't launch to 8 meters but with adjustments in how tightly the ball fit in the barrel, it started launching 8 meters. I don't have my device on me right now, so I'll take a picture of it when I get home.
Here is a photograph of my release mechanism for Scrambler. It's the same design for Air Trajectory, but with a long string attached to it.

Re: Air Trajectory B/C

Posted: February 25th, 2015, 8:16 am
by ImNotSmart
bernard wrote:
bernard wrote: Try using a shorter barrel to get more distance. If your pump is shorter it is compressing less air into the barrel so you want a shorter barrel to get a er increase in pressure. I vary the angle of my barrel to hit different distances. My device originally didn't launch to 8 meters but with adjustments in how tightly the ball fit in the barrel, it started launching 8 meters. I don't have my device on me right now, so I'll take a picture of it when I get home.
Here is a photograph of my release mechanism for Scrambler. It's the same design for Air Trajectory, but with a long string attached to it.
Again, I really appreciate you taking the time to help me out. Are you using a pulley for Air Trajectory as well? I was able to get a trigger involving a pulley system to work pretty well. Also, in order to change how far your device launches, do you change the height from which the weight drops or the angle of the barrel?

Re: Air Trajectory B/C

Posted: February 25th, 2015, 9:28 am
by bernard
ImNotSmart wrote:
bernard wrote:
bernard wrote: Try using a shorter barrel to get more distance. If your pump is shorter it is compressing less air into the barrel so you want a shorter barrel to get a er increase in pressure. I vary the angle of my barrel to hit different distances. My device originally didn't launch to 8 meters but with adjustments in how tightly the ball fit in the barrel, it started launching 8 meters. I don't have my device on me right now, so I'll take a picture of it when I get home.
Here is a photograph of my release mechanism for Scrambler. It's the same design for Air Trajectory, but with a long string attached to it.
Again, I really appreciate you taking the time to help me out. Are you using a pulley for Air Trajectory as well? I was able to get a trigger involving a pulley system to work pretty well. Also, in order to change how far your device launches, do you change the height from which the weight drops or the angle of the barrel?
The pulley is only on my Scrambler, Air Trajectory doesn't have one. I only adjust the angle of the barrel to adjust launch distance since my ball launches when the pump is fully compressed once so a partial compression would not have enough air pressure to launch the ball. You could adjust both drop height of the mass and angle of the barrel or just one of them.

Re: Air Trajectory B/C

Posted: February 25th, 2015, 5:43 pm
by TheGatesofLogic
chalker wrote:
TheGatesofLogic wrote:People asked for hints regarding my elegantly simple solution to the problem of mismatched ball/pipe sizes. Here are two hints:

1. The French

2. Rocket Propelled Grenades

(I am not, however, implying that using rocket propelled grenades or French people in your device is either legal or safe in competition)


And in response to whomever mentioned the FAQ, I am fully aware of the total legality of HDPE golf balls. That's kinda why I use them?
I assume you are referring to a 'sabot' (a french term used in anti-tank rounds): https://en.wikipedia.org/wiki/Sabot

A couple things I'd like to point out:
-Rule 3.f. explicitly says the projectiles must be unmodified. You can't glue or attach anything to them.
-Rule 4.c. explicitly says device parts must automatically return to or stay within the launch area. You can't have a 'fall away' sabot leave the barrel and fly outside of the launch area.

As always though, this is not the place for official comments or clarifications.
You got me, but neither of your clarifications make it illegal, so long as you do it properly. Also, getting the idea and implementing it are two vastly different things. Though I have solved it for myself, I imagine others implementing it will run into other troubles in the process.

Re: Air Trajectory B/C

Posted: February 26th, 2015, 12:13 pm
by ImNotSmart
bernard wrote: The pulley is only on my Scrambler, Air Trajectory doesn't have one. I only adjust the angle of the barrel to adjust launch distance since my ball launches when the pump is fully compressed once so a partial compression would not have enough air pressure to launch the ball. You could adjust both drop height of the mass and angle of the barrel or just one of them.
How are you adjusting your barrel? I can move mine from completely horizontal to about a 65 degree angle with respect to the ground. Would that be enough to cover all distances? Also, what are you using for your weight, and where did you get your materials from? Thanks again!

Re: Air Trajectory B/C

Posted: February 26th, 2015, 1:43 pm
by bernard
ImNotSmart wrote:
bernard wrote: The pulley is only on my Scrambler, Air Trajectory doesn't have one. I only adjust the angle of the barrel to adjust launch distance since my ball launches when the pump is fully compressed once so a partial compression would not have enough air pressure to launch the ball. You could adjust both drop height of the mass and angle of the barrel or just one of them.
How are you adjusting your barrel? I can move mine from completely horizontal to about a 65 degree angle with respect to the ground. Would that be enough to cover all distances? Also, what are you using for your weight, and where did you get your materials from? Thanks again!
By adjusting the barrel, are you asking how I am changing the angle? I think 65 degrees is a good range. My barrel is only around 45 degrees for the 8 meter mark.

I was originally using a dumbbell but that wasn't enough so I've made my own weight from PVC and sand. My PVC-sand weight is quite large and if you take this approach, you could make it much smaller by putting metal inside (though that could be expensive depending on what you use and where you look).

I get almost all of my materials from Home Depot.

Re: Air Trajectory B/C

Posted: February 26th, 2015, 2:39 pm
by ImNotSmart
bernard wrote:
ImNotSmart wrote:
bernard wrote: The pulley is only on my Scrambler, Air Trajectory doesn't have one. I only adjust the angle of the barrel to adjust launch distance since my ball launches when the pump is fully compressed once so a partial compression would not have enough air pressure to launch the ball. You could adjust both drop height of the mass and angle of the barrel or just one of them.
How are you adjusting your barrel? I can move mine from completely horizontal to about a 65 degree angle with respect to the ground. Would that be enough to cover all distances? Also, what are you using for your weight, and where did you get your materials from? Thanks again!
By adjusting the barrel, are you asking how I am changing the angle? I think 65 degrees is a good range. My barrel is only around 45 degrees for the 8 meter mark.

I was originally using a dumbbell but that wasn't enough so I've made my own weight from PVC and sand. My PVC-sand weight is quite large and if you take this approach, you could make it much smaller by putting metal inside (though that could be expensive depending on what you use and where you look).

I get almost all of my materials from Home Depot.
Thank you so much for all of your help! If I need any more advice is it ok if i just pm you?

Re: Air Trajectory B/C

Posted: February 26th, 2015, 3:03 pm
by sjwon3789
I'm trying to get a piston design to work, but I can't find the right materials for it. Like a rubber stopper, can someone suggest something that's more cylindrical, and where I can find it? The cylinder object that I will have to force down, therefore lead to air pressure. It could be soft in object, I just need the right size.

Thanks!

Re: Air Trajectory B/C

Posted: February 26th, 2015, 5:41 pm
by hogger
sjwon3789 wrote:I'm trying to get a piston design to work, but I can't find the right materials for it. Like a rubber stopper, can someone suggest something that's more cylindrical, and where I can find it? The cylinder object that I will have to force down, therefore lead to air pressure. It could be soft in object, I just need the right size.

Thanks!
PVC pipes are probably the material of choice for most people.

http://m.instructables.com/id/Easy-PVC- ... le-Airgun/