Scioly.org

Flavorflav wrote:

starpug wrote:well the drag could be in any direction, this event can come down to cm and the drag could cause the ball to curl just a cm too far left.

Drag is the force that opposes motion through a fluid. By definition, it can only act in the opposite direction of the motion of the projectile. If you are curling to the left, it is because your launcher is imparting a spin, not because of the type of ball.

Clearly the type of ball would have an effect on the motion of the ball. Each ball type will have it's own characteristics. A tennis ball will surely behave differently than a ping pong ball or hackie Sack (whatever that is?), but not necessarilly better or worse. I think the original poster was essentially saying the same thing as you, which is that a combination of spin and wind would cause aerodynamic forces that would unpredictably effect the trajectory of the ball. Which of these forces we call drag (would you call the force of wind pushing the ball sideways drag or lift?) and which is lift, from the spin or relative wind speed, makes little difference, what does matter is that different types of balls will be have different aerodynamic forces. What really matters is that you can consistently predict how these aerodynamic forces will effect the trajectory. If the catapult puts a spin on the ball that could be fine (even good) so long as the spin is the same every time. My biggest concern is what happens if the event is held outdoors (our regional and state trajectory and storm the castle is usually outdoors) and it is really windy. I can see no practical way to build charts that would allow you to accurately predict the impact point in an erratic wind (or even in a constant wind). A really great trajectory device, with great calibration, could still lose to a piece of junk if the competition is on a windy day.

It is true that a tennis ball might curve more (or less, I really don't know) than another type of ball with the same amount of spin. What is definitely true is that the tennis ball will have more friction with the air and therefore lose speed more quickly. This could be an advantage indoors, in that it will fall more vertically which would improve precision indoors, but would make it more vulnerable to the wind effect Capt. Billy is talking about.

Right I guess the projectile is up to the kind of device. If you're using a device that has a tube like a cannon, like ours last year, you need a ball that fits the tube pretty tightly.

i think you guys take this a little too seriously

How strong are torsion springs for a ballista-type device? I've never tried them before (too much work ).
Would you have to de-strengthen your catapult for that to work. Just wondering.

Anonymous T-Bag 69 wrote:i think you guys take this a little too seriously

Scioly is some of our lives ok

starpug wrote:

Anonymous T-Bag 69 wrote:i think you guys take this a little too seriously

Scioly is some of our lives ok

exactly

Anonymous T-Bag 69 wrote:

starpug wrote:

Anonymous T-Bag 69 wrote:i think you guys take this a little too seriously

Scioly is some of our lives ok

exactly

maybe you don't take it serious enough

binary010101 wrote:How strong are torsion springs for a ballista-type device? I've never tried them before (too much work ).
Would you have to de-strengthen your catapult for that to work. Just wondering.

I think it depends on a number of things. Thickness of rope, number of wraps, number of twists etc. I don't think it would be easy to just add torsion bundles to an existing catapult, if that is what you are thinking of.

Anonymous T-Bag 69 wrote:

starpug wrote:

Anonymous T-Bag 69 wrote:i think you guys take this a little too seriously

Scioly is some of our lives ok

exactly

So tell me, what do you do with your time that is so much more important? Troll message boards?

about how long does this event take and is it impounded