Quote:
|
Originally Posted by Lil' Lavery
Im trying to think of an effective way to rifle the ball in a mechanism similar to the softball laucher.
|
Simple: Use two wheels (not just one like the softball launcher), but put them at a slight angle to the direction of travel - for example, the top one is canted 15 degrees to the left (CCW) and the bottom one 15 to the right (also CCW). This is how football launchers work.
Quote:
|
Originally Posted by iCurtis
With the spin the ball expeiriences being launched, and with the lightness of the ball, those balls will be going every which way immediately after they go through the launcher.
|
I disagree, and I see no need for a 'barrel'. In a protoype I built today (see photo), the balls went very very repeatably to the same spot. The biggest variable will be the supply voltage (= motor speed), but the astute student will figure out how to compensate for that ;-)
Quote:
|
Originally Posted by I'mwithstupid^
I think that it would be easy to do a pneumatic system that would be fast.
|
Umm, using what energy source? A tennis ball launcher uses what is essentially a vacuum cleaner, blowing instead of pulling, and shoots the ball out of a 'barrel'. Longer barrels shoot further and flatter, and a screw-thingie on one side imparts spin. But, a 7 ball needs a LOT of air volume. Do the math with a 2' long barrel - what is the volume of the barrel in cubic feet, and how many cubic feet per minute at (60?) PSI can that KOP compressor supply? That gives you your best firing rate, BUT there is no place to store that volume of air at 60 PSI on a legal robot.
The way I see it, the only viable options are wheel-based and spring-based launchers. (A trebuchet is spring-based
[EDIT: No, it is powered by a falling mass[/EDIT], and I agree, it would be soooo cool).
In the photo, that is an 8" wheel. At about 1300 RPM it launches a 7" soccer ball about 10 feet (from a table 40" from the floor), and in ten tries they all landed within an inch of each other.
The biggest issues are balance of the wheel - it wobbles a lot at 1300 RPM, it's not made for that - and the huge black marks the rubber leaves on the ball.
Don