Air Trajectory B/C
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Re: Air Trajectory B/C
Ok so I'm trying a piston design. It's pretty simple - I have a 4 inch PVC pipe which connects to a thin plastic tube which connects to the barrel where the ball is launched from. My piston is a 3 inch PVC pipe with 2 caps on the ends which are just the right size so when I put my piston PVC in the bigger PVC, it's relatively airtight. My weight is also inside my piston. However, when I drop the piston, it goes about 1/3 of the way down when the ball launches barely a foot. Any tips to make sure this doesn't happen? I could partially prevent this by making my piston drop faster - is there a way to do this? Are there better ways to make my piston more airtight than using a plastic cap which coincidentally is a similar size to the inside of my compression chamber?
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Re: Air Trajectory B/C
Why not try making the piston and weight two separate things. You could start by positioning the piston about 6 inches up the pipe and then drop the weight from a much higher height . Hope this makes sense.ImNotSmart wrote:Ok so I'm trying a piston design. It's pretty simple - I have a 4 inch PVC pipe which connects to a thin plastic tube which connects to the barrel where the ball is launched from. My piston is a 3 inch PVC pipe with 2 caps on the ends which are just the right size so when I put my piston PVC in the bigger PVC, it's relatively airtight. My weight is also inside my piston. However, when I drop the piston, it goes about 1/3 of the way down when the ball launches barely a foot. Any tips to make sure this doesn't happen? I could partially prevent this by making my piston drop faster - is there a way to do this? Are there better ways to make my piston more airtight than using a plastic cap which coincidentally is a similar size to the inside of my compression chamber?
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Re: Air Trajectory B/C
Would that allow the weight to slam into the piston with more force to launch the ball further?Xystus wrote:Why not try making the piston and weight two separate things. You could start by positioning the piston about 6 inches up the pipe and then drop the weight from a much higher height . Hope this makes sense.ImNotSmart wrote:Ok so I'm trying a piston design. It's pretty simple - I have a 4 inch PVC pipe which connects to a thin plastic tube which connects to the barrel where the ball is launched from. My piston is a 3 inch PVC pipe with 2 caps on the ends which are just the right size so when I put my piston PVC in the bigger PVC, it's relatively airtight. My weight is also inside my piston. However, when I drop the piston, it goes about 1/3 of the way down when the ball launches barely a foot. Any tips to make sure this doesn't happen? I could partially prevent this by making my piston drop faster - is there a way to do this? Are there better ways to make my piston more airtight than using a plastic cap which coincidentally is a similar size to the inside of my compression chamber?
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Re: Air Trajectory B/C
Yes it would!. At fist I had both combined and had a very similar problem to the one you have. But now I am able to reach the required distance.ImNotSmart wrote:Would that allow the weight to slam into the piston with more force to launch the ball further?Xystus wrote:Why not try making the piston and weight two separate things. You could start by positioning the piston about 6 inches up the air chamber and then drop the weight from a much higher height . Hope this makes sense.ImNotSmart wrote:Ok so I'm trying a piston design. It's pretty simple - I have a 4 inch PVC pipe which connects to a thin plastic tube which connects to the barrel where the ball is launched from. My piston is a 3 inch PVC pipe with 2 caps on the ends which are just the right size so when I put my piston PVC in the bigger PVC, it's relatively airtight. My weight is also inside my piston. However, when I drop the piston, it goes about 1/3 of the way down when the ball launches barely a foot. Any tips to make sure this doesn't happen? I could partially prevent this by making my piston drop faster - is there a way to do this? Are there better ways to make my piston more airtight than using a plastic cap which coincidentally is a similar size to the inside of my compression chamber?
Last edited by Xystus on March 1st, 2015, 4:42 pm, edited 1 time in total.
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Re: Air Trajectory B/C
Are you using a device similar to mine? How did you keep the piston suspended 6 inches above the bottom of the compression chamber? But thanks for the help, I'll be sure to try it out.Xystus wrote:Yes it would!. At fist I had both combined and had a very similar problem to the one you have. But now I am able to reach the required distance.ImNotSmart wrote:
Would that allow the weight to slam into the piston with more force to launch the ball further?
Re: Air Trajectory B/C
Hello all,
We are not having much luck with the triggering device. So far for testing, kids have been holding a string tied to a weight from a meter away and just letting go of the string. Based on the rules this might be a violation.
Is it okay to place the weight on a ledge and push it with a meter stick from a distance, is that a valid triggering without violating the rules. Or is there anything better to do. Weight being used is "dumbbell".
Any help will be highly appreciated.
Thank you
We are not having much luck with the triggering device. So far for testing, kids have been holding a string tied to a weight from a meter away and just letting go of the string. Based on the rules this might be a violation.
Is it okay to place the weight on a ledge and push it with a meter stick from a distance, is that a valid triggering without violating the rules. Or is there anything better to do. Weight being used is "dumbbell".
Any help will be highly appreciated.
Thank you
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Re: Air Trajectory B/C
actionpotential wrote:But goodcheer I see that you're putting the 1.5 inch metal pipe inside a PVC pipe, so that may minimize temperature sensitivity. Definitely test your device if the cold will matter. You could just bring your device outside for a few minutes, bring it back inside, and test it again.
Yes, what you have said matches what we have experienced. We have had issues with consistency and the metal pipe might very well be the problem. We realized the longer we practiced, the more we were blowing into the device to inflate the bottle and warming it up by our breath. We actually were not thinking about the pipe, but the warm air in the bottle. However, our regional is Sat. and we are going with what we have and hope we can make good adjustments for our second shots if the first shots are not very accurate. Thanks for the pointers.
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Re: Air Trajectory B/C
The stick might work, but it might need to be longer than 1 meter since the rule is you cannot be within 1 meter of the launch area. The device sits within the launch area and the triggering device must extend at least 1 meter outside of the launch area, not 1 meter away from the device. There are better solutions. Bernard submitted a photo earlier of a trigger and another suggestion mentioned was to use an archery release. Basically, attach one end of a string to the mass and the other end to the release which is located somewhere on the device. Then attach a second string to the trigger and that string extends out of the launch area. The trigger can sit directly above the mass or you can run the string through a pulley or eyebolt and locate the trigger at the base of the device. Hope this is not too confusing.vid_123 wrote:Hello all,
We are not having much luck with the triggering device. So far for testing, kids have been holding a string tied to a weight from a meter away and just letting go of the string. Based on the rules this might be a violation.
Is it okay to place the weight on a ledge and push it with a meter stick from a distance, is that a valid triggering without violating the rules. Or is there anything better to do. Weight being used is "dumbbell".
Any help will be highly appreciated.
Thank you
Re: Air Trajectory B/C
Thanks goodcheer. This is pretty helpful. I will look into the "archery release" in a sporting good store.
The weight being a dumbbell it is hard to keep it steady when tied to a string, it seems to lean towards one end causing the weight to fall a little to the side on the throw ball causing inconsistence in the distance the ping pong ball is launched.
We had better luck with pushing with the meter scale, maybe if I attach another foot ruler to the meter stick which would mean it is over a meter. If this complies with the rules then I would like to pursue this option.
Please let me know your thoughts.
Thank you again for your help.
The weight being a dumbbell it is hard to keep it steady when tied to a string, it seems to lean towards one end causing the weight to fall a little to the side on the throw ball causing inconsistence in the distance the ping pong ball is launched.
We had better luck with pushing with the meter scale, maybe if I attach another foot ruler to the meter stick which would mean it is over a meter. If this complies with the rules then I would like to pursue this option.
Please let me know your thoughts.
Thank you again for your help.
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Re: Air Trajectory B/C
Glad to offer suggestions. I might be missing something, which is easy for me to do, but it seems the stick would need to be somewhere around 1.5 meters long; since the competitor must be 1 meter away from the launch area and the device sits within that area about 0.5 meter (if it is placed in the middle). If you need a longer stick, might try a broom handle or cane pole, etc. If anyone else sees anything wrong with this approach, please jump in.vid_123 wrote:Thanks goodcheer. This is pretty helpful. I will look into the "archery release" in a sporting good store.
The weight being a dumbbell it is hard to keep it steady when tied to a string, it seems to lean towards one end causing the weight to fall a little to the side on the throw ball causing inconsistence in the distance the ping pong ball is launched.
We had better luck with pushing with the meter scale, maybe if I attach another foot ruler to the meter stick which would mean it is over a meter. If this complies with the rules then I would like to pursue this option.
Please let me know your thoughts.
Thank you again for your help.
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