Boulder inconsistency issue

[quillford]

Throughout most of build season we tested with only one boulder and tuned everything based off that one boulder, but as soon as we got a new one we noticed that it shot completely differently. We resolved to simply be a low goal shooter for our first regional, but now I want to look at the high goal again. I was thinking of increasing the compression (we're at 1.5" IIRC), but we were using bags for most of our testing and more compression would stall the motors on intake. Since switching to 775pros, we have not tried more compression. Does anyone have any other suggestions?

[Arhowk]

Gearbox? I think we're running 30:1s (don't quote me on that) on single bag motors with a ton of compression and we have no pickup issues at all

[quillford]

Originally Posted by Arhowk

Gearbox? I think we're running 30:1s (don't quote me on that) on single bag motors with a ton of compression and we have no pickup issues at all

We're running them with versaplanetaries 1:1 just for the ease of mounting. Are you shooting in the high goal with that much reduction?

[Monochron]

Originally Posted by quillford

We're running them with versaplanetaries 1:1 just for the ease of mounting. Are you shooting in the high goal with that much reduction?

Just for reference, two 775Pros at 3:1 reduction is more than enough to make high goal shots. Tuning your compression, ball feeding, and geometry is often the harder problem. A lot of teams are doing well with 3 inches of compression.

[quillford]

Originally Posted by Monochron

Just for reference, two 775Pros at 3:1 reduction is more than enough to make high goal shots. Tuning your compression, ball feeding, and geometry is often the harder problem. A lot of teams are doing well with 3 inches of compression.

I don't think we have any 3:1 stages. Would a 775pro with a CIM-ile on each side work?

[Andrew Schreiber]

Originally Posted by quillford

I don't think we have any 3:1 stages. Would a 775pro with a CIM-ile on each side work?

Try it. Welcome to prototyping.

[george.tan]

We had some luck using mini CIMs. I think you'll have the ball inconsistence issue regard less of which motor you're using. I know a used ball have a different trajectory compare to a brand new ball. I think you really need to take some time to find the sweet spot for your shooter. Don't go for the long shot. Dial in your shot at the base of the castle, that should give you a few more points per cycle. Good luck prototyping and enjoy the process.

[wilsonmw04]

Originally Posted by quillford

Throughout most of build season we tested with only one boulder and tuned everything based off that one boulder, but as soon as we got a new one we noticed that it shot completely differently.

Welcome to the lessons of Rebound Rumble. After playing with the scoring pieces for a few minutes, we ruled wheeled shooters out. The balls were just too wonky. It really doesn't matter what motors you use. The inconsistencies will persist.

[Deke]

There are ways to shoot the ball where the inconsistencies from ball to ball don't affect the trajectory. Keep playing with grip, speed, ball centering, and compression and I'm sure you'll find success with a wheeled shooter.

[orangemoore]

Reduction and gearbox choice offers no help when talking about this unless you include wheels sizes as well.

How am I going to know if you use 20" wheels for 2" wheels.

The only information I have is RPM

[Hitchhiker 42]

Just as another approach (instead of the mechanical side), here's a programming side:

Tune a PID control with a feedforward on the shooter motors. For us, this significantly decreased ball consistency problems with high shots. Although the ball is shot out really fast, there is enough time to somewhat correct the RPM back to your set RPM as the shooter is slowed by the ball going through it.

[Max Boord]

Originally Posted by quillford

I don't think we have any 3:1 stages. Would a 775pro with a CIM-ile on each side work?

Thats what 4592 is running. we found 2 inches of compression was enough to shoot high goals from the low bar although I would not be surprised if 3-4 inches of compression would be more ideal. We currently run 3 4x7/8 colson wheels per side at 3370 RPM for most ranges. Also, the mechanism pushing the ball into the shooter wheels had a large effect on accuracy. Switching from pushing the ball by hand to a pneumatic indexer altered our RPM by about 200 to get the same shot.

[Cash4587]

there's still time to join #TeamPneumatapult

[wilsonmw04]

#TeamPneumatapult for life.

[carpedav000]

Originally Posted by wilsonmw04

#TeamPneumatapult for life.

#SpringPunchers for the win!