what was the best shooting mechanism for 2016?

[Amit3339]

During the build season we had a discussion about our way to shoot the boulders into the high goal. The main two mechanisms were(of course) a catapult and a wheeled shooter. Throughout the season I've seen some amazing teams that used both methods and reached an amazing consistency, but somehow I always thought that the catapult is much more consistent because it didn't had nothing to do with the condition of the boulder.
I was wondering if someone on CD have some data about the type of shooting mechanism that teams that were on Einstein had?
I would be happy to hear what other people think? was the catapult more effective or was it the wheeled shooter?

[Sperkowsky]

The best shooting mechanism was the optimized one. Whether it had wheels, or a catapult wasn't the point.

I have seen extremely successful wheeled shooters and catapults as well as extremely unsuccessful wheeled and catapults.

Its all in the execution.

[TechWaffle]

This is just guessing, but the catapult could probably be unreliable sometimes if the springs got stretched out. The wheeled shooter is effective, but as you said it has much to do with the condition of the boulder. Also if the wheels don't spin fast enough (be a programming or mechanical issue) it won't shoot out as expected. "Its is all in the execution"

[carpedav000]

I still say the linear puncher is the best mechanism (if done well). However, hooded flywheel shooters seemed to be the most successful.

[scott.smith]

Both wheeled shooters and catapults were equal I feel, but the best wheeled shooter was the turret-style from 254, 179, and 5172. The best catapult was between 148 and 118. (Texans know catapults, I guess) The best "Other" shooter was from 3360 and their "mini catapult" inside their arm.

[Amit3339]

Originally Posted by scott.smith

Both wheeled shooters and catapults were equal I feel, but the best wheeled shooter was the turret-style from 254, 179, and 5172. The best catapult was between 148 and 118. (Texans know catapults, I guess) The best "Other" shooter was from 3360 and their "mini catapult" inside their arm.

You have to include 1501 and their turret I think. They been really successful with it. I dont really know what mechanism did 330 used but they also had a solid shooter that scored well, probably gets them to the category of the best "Other" shooters.

[Aidan Cox]

Originally Posted by scott.smith

Both wheeled shooters and catapults were equal I feel, but the best wheeled shooter was the turret-style from 254, 179, and 5172. The best catapult was between 148 and 118. (Texans know catapults, I guess) The best "Other" shooter was from 3360 and their "mini catapult" inside their arm.

When it comes to "other" shooters, I'd throw 1519 into the mix for one of the best linear punchers.

[scott.smith]

Originally Posted by Amit3339

You have to include 1501 and their turret I think. They been really successful with it. I dont really know what mechanism did 330 used but they also had a solid shooter that scored well, probably gets them to the category of the best "Other" shooters.

330 had a good linear punch mechanism (A piston hit the ball), but I feel it had to be a bit to close to the goal. I think that 3360 had a shooter that could shoot from farther away, and the batter, which made them more flexible. As for 1501, they had a great turret shooter, but my list wasn't definitive, it was just some robots with good turrets.

[Chris is me]

Originally Posted by Sperkowsky

The best shooting mechanism was the optimized one. Whether it had wheels, or a catapult wasn't the point.

I have seen extremely successful wheeled shooters and catapults as well as extremely unsuccessful wheeled and catapults.

Its all in the execution.

Now the real lesson is to see that this applies to nearly every year. Great execution can make a wide variety of concepts work at the highest levels. The "right" mechanism depends on a variety of factors - you have to weigh what your team has experience with, what your team can prototype the best, what your team can optimize most easily, what has the right tradeoff between performance ceiling and simplicity, etc.

I think my team should have done a catapult, and that more teams should have done catapults than wheeled shooters. It seems like double wheeled shooters were the easiest to get range and repeatability out of, and they did not suffer as many problems with the goal chains as backspin (one wheel) shooters seemed to, but both could be optimized.

[jijiglobe]

Although there were many different successful shooter designs this year, I think the best ROI was in the hooded flywheel shooter, which was why it was so prevalent. Here's why:

1) Hooded flywheel shooters are space efficient over other wheeled shooters because they use less wheels, and if you design for it, the hood can pop down under the low bar (saw a few teams do this).

2) Hooded flywheel shooters are relatively easy to test/tune. Most catapult designs require mechanical tweaks to adjust power and speed. As long as your shooter wheels are overpowered, you can tune them down with encoders until you get the desired effect.

3) Hooded flywheel shooters put a backspin on your ball. Due to aerodynamics that I don't exactly understand, this means that the ball goes further, but it also means that if you hit the top of the goal, the ball has a high probability of rolling in. (hitting the top of the goal is far more common than the bottom because the robots are shooting up at the goal from below.

4) Hooded flywheel shooters are relatively easy to design. The only moving components are a single axle with wheels on it. No potential energy storing devices are necessary. Most teams have also tried this kind of shooter at some point in their history.

5) While both catapults and wheeled shooters can get worn down. Wheel wear is clearly visible, while springs or surgical tubing getting stretched is not as easy to spot.

I'm not saying necessarily that hooded flywheel shooter is objectively the best (because each design has its own merits). I am saying that the hooded flywheel shooter gives the best ratio of time spent (designing, building, tuning) to effectiveness.

[Chris is me]

Originally Posted by jijiglobe

3) Hooded flywheel shooters put a backspin on your ball. Due to aerodynamics that I don't exactly understand, this means that the ball goes further, but it also means that if you hit the top of the goal, the ball has a high probability of rolling in. (hitting the top of the goal is far more common than the bottom because the robots are shooting up at the goal from below.

All other things equal (specifically, tip speed / torque of the flywheel, and energy transfer between the wheel and the ball), a hooded shooter will throw a ball half as fast as a double wheel shooter.

For my team this was the biggest challenge with our shooter - actually getting it to shoot far enough to make a shot from the outer works was difficult with just one mini-CIM on the shooter. We probably could have done it with two, but then packaging became an issue.

[jijiglobe]

Originally Posted by Chris is me

All other things equal (specifically, tip speed / torque of the flywheel, and energy transfer between the wheel and the ball), a hooded shooter will throw a ball half as fast as a double wheel shooter.

And this is why 775Pros are a godsend.

Crazy power output? check

Fast as heck so I don't have to gear up? check

I would also argue that the main reason that the two wheeled shooter is faster is because it has twice as many motors. If you really need the extra power Vex has you covered

[jajabinx124]

I just realized the entire Carson division winning alliance had catapults.. Go catapults!

Anyway, I agree with most of the posts on this thread. It depends on the execution and implementation behind it. Whichever method of shooting you go with, find a way to implement it well and make it flexible. (for example, the ability to shoot from multiple positions from the field, outerworks, batter, etc.)

[Chris is me]

Originally Posted by jijiglobe

I would also argue that the main reason that the two wheeled shooter is faster is because it has twice as many motors.

It's not an argument or random postulation, it's physics. It's the difference between a ball being "rolled" or "tossed" out of a shooter. Let's make some assumptions - zero slip between the wheel and the ball, zero slip between the ball and the hood of the shooter, perfect energy transfer, wheels don't even slow down, whatever.

A two wheeled shooter contacts both sides of the ball at a certain tip speed, V. Both edges of the ball are being moved at the same speed, so the ball does not rotate at all, it is fired straight out of the shooter. The center of the ball therefore also moves at V.

Now consider a hooded shooter. The flywheel rolls one edge of the ball forward at V, and the other side of the ball is rolling along the flywheel. Instantaneously, the tip velocity of the other side of the rolling ball is zero (or is it the other way around...) - so the velocity of the center of the ball is V/2. When the ball exits the shooter (is released from the constraints placed on each end of the ball) it'll travel at the speed the center of the ball is moving.

Real world factors will make your result vary, but in general, all other things equal, hooded shooters do move balls half as fast (and half as far) as two wheeled shooters. This is not due to having fewer motors - tons of teams put more than one motor on a ball. This is just due to the dynamics of a ball rolling through a shooter.

A 775pro's power is greater than a mini-CIM, yes, but there are also good reasons not to spin your flywheel at 19,000 RPM, and tip speed is far from the only factor that determines how far your ball will fly. You probably end up gearing the 775 down to a speed closer to the mini-CIM, but with more power, which would probably reach a greater distance yeah. Too bad you can't buy those right now...

[serenagh]

Originally Posted by scott.smith

Both wheeled shooters and catapults were equal I feel, but the best wheeled shooter was the turret-style from 254, 179, and 5172. The best catapult was between 148 and 118. (Texans know catapults, I guess) The best "Other" shooter was from 3360 and their "mini catapult" inside their arm.

For a non-turret style shooter which was beautiful optimized - see 971. I'd definitely say they were one of the best shooters at worlds, coupled with a beautiful two ball auto. Also, 1678.

Between 148 and 118, I'd have to say 148 - they scored 12 balls in one match (with 1678 putting up ten more) for the "most balls scored" in the 270 point match during Hoppers divisional eliminations. But kudos to both Texas teams for showing us how catapults should be done.