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So far we have only calibrated for the ground target but we should be able to hit the raised target with no problem

Raised target can be practically anywhere, you know...

zyzzyva98 wrote:Raised target can be practically anywhere, you know...

Actually not, I can name quite a few places it can't be...

It's pretty straight forward really, once you know the physics of the event that is.

Kinematics I choose you!

could you elaborate on how we could use kinematics because so far we have been testing extensively however it seems impractical to calibrate for all the points that are possible.

NIXINATOR wrote:my catapult has so much force behind it that when using a pin it pulls the whole catapult with it
any ideas for another release mechanism?

Our release mechanism is a little hard to explain... it doubles as our tension adjustment.
Essentially, we have our catapult arm, which has a little metal tab sticking out at the end; it pulls back, and slots under the rim of a large washer that's held on a threaded rod (which stands vertically at the back of the device) by two wingnuts. This threaded rod is attached at the bottom to an axle, and to launch, you just pull back the threaded rod like a lever, pulling the washer out of the way of the tab and letting the arm swing forward. To adjust tension, you move the washer up or down the rod. There's a small bungee cord behind the rod, so when you let go of it after launch, it springs back into place to avoid being out of specs.

i don't know if this has ever happened to any of you, but we were testing the other day and we happened to try another tennis ball and the distance achieved was way off. So we looked into it trying many different tennis balls and they all got different distances. These balls were almost the same mass and same brand but they launch really different. Why do you think this is? When we use the same tennis ball it is really consistent.
So now we have to stick with one ball and hope nothing happens to it

I don't know the reason why similar balls from the same pack preform differently, but I have observed the same phenomenon.

Does anyone have a good explanation?

anon y mouse wrote:I don't know the reason why similar balls from the same pack preform differently, but I have observed the same phenomenon.

Does anyone have a good explanation?

If you are using any sort of lubrication on the area where the ball is then the ball you use a lot might have some residue on it that causes it to move a little freer

You could also in the tennis ball case have more or less fuzz on the ball.

I guess the ball making process isn't perfect :/ if all else fails

We've noticed the same thing with our tennis balls. We labeled them to avoid confusion. There's not much you can really do about it, unless you know someone in the tennis ball-making industry.