2 new ball launcher designs

I honestly don’t know if these designs have been made before, but I have yet to encounter them in my 2 years of vex.
I was brainstorming ball launcher ideas, and I’ve come across these 2.

  1. rotary puncher (unless it already has a name)

so for this design I was thinking you’d have a c channel, that rotates around a still point. when the c-channel is pointing down, it would be touching a place for the balls to rest. you would use motor power to rotate the c-channel back, and have elastics pulling it back to the downwards position. this way, when you released motor power, the channel would swing back and sort of kick the ball out of the little resting place, and you could have another ball take its place.

pros:
good for v5 because there is only one spot being powered on the launcher, and you’d need a good amount of torque.
it seems like this design could operate fairly quickly, probably about the same rate as a linear puncher.
cons:
I doubt it would be too accurate
could take up a lot of space if you make the c-channel long.

now for the second design:

Slingshot

for this idea, you would have a slingshot-type thing going on. There would be a c-channel bit that goes behind the ball, that can move freely on some low-friction liner tracks. then, you would need 2 posts on a linear device that when pulled back, stretches out elastics from between the posts and the back bit. then, there would be a catch or something holding back the back part, so that when the catch is released, the back part slides forward across the linear tracks to meet the posts, upon which the ball flies out. to reload, the linear device would be retracted, and the back part would be re-attached to the catch.

pros:
-with the linear tracks, could potentially be very accurate
-you could possibly even attach this shooter at an angle, and program in 2 distances that you would pull the linear device out to, so that
you can control where the ball goes without moving around.
-seems like you would get a lot of force on the ball from this.
cons:
-probably very motor consuming. I wouldn’t use this design for v5, however I have no idea whether or not I’ll be using v5 next year, so…
-probably also space-consuming.
-a slow fire rate I would imagine.

All in all, I still think a flywheel will be the way to go, but I want to see if anyone can improve upon these designs. I hope to make prototypes of each when I get the chance.

We started to build a “rotary puncher” around the end of our Nothing But Net season. It had promise, but it was never completed as we didn’t qualify for worlds that year. The structure was complete, but we never got around to getting any elastic on it, nor motors.

ah too bad. =\ was it better than a flywheel?

Might have been, but our robot was janky. The initial dual flywheel that I built with rubber shaft collars was supposed to be prototype. It ended up being the main launcher the entire season. Our linear puncher was installed in the days leading up to states. I am not very qualified to answer that question. :stuck_out_tongue:

ah. well I wasn’t even part of nbn so… =P

We thaught a rotary puncher could be a good idea for this season, it would be more compact than a linear puncher which would be useful this season with so many subsystems. However, we decided to dismiss the idea as we didn’t feel it would launch the ball as straight or as reliably as a linear puncher or flywheel, however, we have never tested this so I would be interested to see if it could work.

It sounds to me like your slingshot design functions the same as a regular slipgear puncher, with some unnecessary complications. Could you elaborate a bit on how it differs and why it could be a better alternative?

The difference is in the length of the applied impulse. A puncher could have less than half a second of contact, where the slingshot described would very likely be significantly longer.

Ah, okay. That makes sense.

That doesn’t make any sense at all. First, what do you mean by the length of the applied impulse? I’m guessing you don’t mean “impulse” when you say “impulse.” Second, consider the following example: which touches a tennis ball for longer and which can make it go faster, a tennis racket while serving the ball or a hand while throwing the ball? When comparing the effects of two different forces, you cannot only look at the times involved.

Regardless, if you put all the energy from the same stretch of elastics into a puncher and the puncher hits the ball elastically and stops, both the energy and the impulse given to the ball are the same as if they had been given directly to the ball. Now, that collision won’t be elastic, some energy is lost there, and that might make a difference.

An impulse is an applied force over a period of time.

Correct, but I never solidly indicated that it was for the better or for the worse.

I know quite well what impulse is, have dealt with it both relativistically and not, understand what Newton’s second law actually is, etc. Knowing all that, your statement doesn’t make sense. Impulse doesn’t have a length either in the physical sense or in the time sense. Noting you seem to have a sense of what impulse is, you probably meant to say “duration over which the force is applied” or similar. OK. But that’s not necessarily changing the impulse at all. Changing the amount or direction of the impulse would change the impulse.

and you could adjust the trajectory of the ball.

@callen, I think my wording has obviously been confusing. You are interpreting my point correctly.

My original statement made a few assumptions:
1. The impulse was constant, resulting in an inverse relationship between force and time.
2. The efficiency of the launcher may be different when the acceleration is drawn out over different periods of time.

I do appreciate your criticism, but I feel this is separating from the thread’s topic.