# Ping pong ball launcher

Hi there. I'm at bath uni. Our group is building a ping pong ball launcher. Here are some issues we encountered.

If the ball is to drop vertically into a 40mm tube with air flowing at 6bar(does this mean anything?) will it drop in or will it blow back out.

Also I'm not to sure how to calculate the drag force on the TT ball through the air. I need to calculate its range and trajectory. Obviously this will change when spinning. Is it possible to take spinning into account on paper?

Is there a standard integral i need to calculate the drag at each velocity?

Any help will do.

Thanks

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brewnog
Gold Member
They won't thank you here for cross-posting.

However, you will be forgiven, since you're from Worksop.

FredGarvin
chris_tams said:
If the ball is to drop vertically into a 40mm tube with air flowing at 6bar(does this mean anything?) will it drop in or will it blow back out.
Think about how an airbrush works...

I dont know much about that kind of stuff but I know alittle. Concerning the loading question, the balls should actually be sucked into the barrel as long as the hopper tube is perpendicular to the barrel. As for the drag and trajectory this site should help http://lennon.csufresno.edu/~nas31/nsa/pballCalc.html it's for paintball but it's similar to your question.

Well i know that if you make it as a orange gun, and you fired a orange the orange would get to speeds of about 300km/h and travel 1km there abouts, but that is using a internal combustion. Any way would'nt the line of fire be fairly linear? so you could just graph it.

brewnog
Gold Member
Sowhatalot said:
Well i know that if you make it as a orange gun, and you fired a orange the orange would get to speeds of about 300km/h and travel 1km there abouts, but that is using a internal combustion.
What, at 6 bar like the OP stated? Don't think so!

Any way would'nt the line of fire be fairly linear? so you could just graph it.
No, gravity would ensure that the path isn't linear.

Chris, is this a first year group build project? Unless you're on an AE course, I'd probably expect them to be looking for you just to use kinematics and some basic aerodynamics (drag) to determine the flight details. You're right in stating that spin will affect your trajectory, but I don't think there's any way you'll be able to take this into account, since you have little idea of how the ball will emerge from the launcher. Anyway, you haven't posted for a while so I guess you've got exams on at the moment...