Team 67's incredible shooter

[Bstep]

Thank you for the responses Mr. Freeman, I appreciate your openness. We've been very inspired by your team in the past and this year is certainly no different.

[JamesTerm]

Originally Posted by Adam Freeman

Thanks for the compliments. Our shooter is pretty good. I wouldn't say it's the best (I personally love 2169's shooter), but it will hold it's own with the best of them.

Shooter Details:
We are using the 3.875" banebot wheels with the orange rubber compound - - http://banebots.com/pc/WHB-HS4-398/T80P-394BO-HS4

It's set up for about a 1/2" of compression on the disk.

For speeds we are running a AM-9015 on the first wheel with a pulley setup at 42T:12T ratio (~4500RPM). The next wheel is a Banebot 550, setup on a 30T:12T ratio (~7700RPM). The third wheel is also a 550 with a 22T:12T ratio (~10500RPM).

-Adam

Thanks for sharing this information... I hope when the season is over other teams will share these numbers as well and what methods they used to work out how to come to these decisions.

[Aren Siekmeier]

Originally Posted by Adam Freeman

Thanks!

The idea to use banebot wheels came from Allen Gregory and 3847's blog. We were originally trying to use colson wheels, but those transferred too much of the frisbee to the wheel quickly and shot very inaccurately. I emailed Allen and asked about how well their banebot wheels were holding up. He sent back pics of all three different compounds (green, orange, and blue). The green seemed to be worn down really bad, the orange and blue not so much. So we purchased both orange and blue.

...

-Adam

Good to know.... We've been using the green wheels all year (not sure if there was any particular reason), and we did see a LOT of wear after our first event Northern Lights - even having to replace all 3 mid North Star. We may get a hold of the orange and blue ones to try them at champs (or at least have them on hand).

[jdaming]

Originally Posted by Adam Freeman

Thanks for the compliments. Our shooter is pretty good. I wouldn't say it's the best (I personally love 2169's shooter), but it will hold it's own with the best of them.

What do you like best about 2169's shooter? I couldn't seem to find a picture of it anywhere.

[Adam Freeman]

Originally Posted by jdaming

What do you like best about 2169's shooter? I couldn't seem to find a picture of it anywhere.

I just liked the way it shot. It had a very high release point, that was very hard to block.

I'm not sure I saw it miss in any of the matches that I watched from the Colorado Regional eliminations.

I haven't really seen pictures of it....just videos from the webcast. I will definitely have to check it out in St. Louis.

[Kevin Leonard]

I think it's interesting how differently the two long-range shooter whose shooters I've seen approached the FCS concept. While 67 is using three banebots, 195 has a GIGANTIC wheel on a circular shooter. It's awesome.

[Adam Freeman]

Originally Posted by Thunder910

I think it's interesting how differently the two long-range shooter whose shooters I've seen approached the FCS concept. While 67 is using three banebots, 195 has a GIGANTIC wheel on a circular shooter. It's awesome.

I can only talk to what we did. In our case, we were trying to keep the weight of the shooter down as much as we could, since we were going to be tipping the robot back to climb up the corner.

I'm not really sure how much weight savings we actually achieved, since I believe the shooter assembly (shooter, plate, frame, etc..) ended up weighing about 15lbs. So when you add up all the bearings, bearing blocks, wheels, and other parts the weight went up pretty quickly.

We prototyped multiple shooter configurations, but the linear style offered the best performance for us, given the packaging configuration we had to fit for the climber.

Once we added the third wheel, we really started to get the FC distance we needed. Without it (double banebot wheels) we were only getting about 40'.

[joelg236]

Originally Posted by Adam Freeman

Once we added the third wheel, we really started to get the FC distance we needed. Without it (double banebot wheels) we were only getting about 40'.

Might be a strange question, but why only three wheels as opposed to 4, 5,6, etc? Weight, practicality? Was there something that made 3 the "sweet spot"?

[Adam Freeman]

Originally Posted by joelg236

Might be a strange question, but why only three wheels as opposed to 4, 5,6, etc? Weight, practicality? Was there something that made 3 the "sweet spot"?

That's just what we needed to get the distance. I can't say we thought about adding any more than 3.

We did experiment with a wheel on the opposite side of the main shooter wheels, to eliminate curve. But, it didn't do much and kinda got forgotten about.

[JamesTerm]

Originally Posted by Adam Freeman

That's just what we needed to get the distance. I can't say we thought about adding any more than 3.

We did experiment with a wheel on the opposite side of the main shooter wheels, to eliminate curve. But, it didn't do much and kinda got forgotten about.

That is an interesting reason to try the wheel on the opposite side... we thought about that for the reason to trade less angular velocity for more linear.

Originally Posted by Thunder910

I think it's interesting how differently the two long-range shooter whose shooters I've seen approached the FCS concept. While 67 is using three banebots, 195 has a GIGANTIC wheel on a circular shooter. It's awesome.

The 3997 screaming chickens have a circular shooter that I believe could have been long range, because man that thing had some serious power at close range, low to ground feed drive, steep angle... when it scored the 3 point... it went in about 45 degrees with no hint of even coming close to leveling out... it slammed into the goal. I personally like this.

[Chris is me]

I think 67's curve really seems to help their FCS ability and I wouldn't make an effort to eliminate it. However, for those of you reading this thread looking to copy 67's shooter but without the curve, I thought I'd share a tip. We built a somewhat similar shooter this year (multiple orange Banebots on a linear shooter, hitting about 40-45 feet with two of them) and had a similar curve to 67 near the end of our trajectory. We found that for us, the best solution was to constrain the frisbee as much as possible in the shooter. While a 2" opening would often result in a frisbee that veered in one direction after about the 25 foot mark, a smaller opening constrained with smooth plastic (especially on the side with the wheels) would always go perfectly straight.

I really admire the 67 robot this year. I think it's a design strategy a lot of teams attempted in various ways, but few could execute so well. I wish we were smart enough to come up with some of their design details in season, but I highly doubt we could have executed like they have.

[Bennett548]

Originally Posted by Adam Freeman

Thanks!

...
I think the shooter accuracy is actually falling off from what it was at Troy and early MSC, so we might replace all the wheels when we get to Champs

I wonder if that might have had more to do with disc wear than wheel wear? We were seeing some pretty nasty discs by the end of quals at MSC.

Are the game pieces at CMP usually brand new?

[Peyton Yeung]

Originally Posted by launchloop17

I wonder if that might have had more to do with disc wear than wheel wear? We were seeing some pretty nasty discs by the end of quals at MSC.

Are the game pieces at CMP usually brand new?

For a couple of rounds. Then they usually use new ones for elims.

Peyton

[Bstep]

Originally Posted by Chris is me

While a 2" opening would often result in a frisbee that veered in one direction after about the 25 foot mark, a smaller opening constrained with smooth plastic (especially on the side with the wheels) would always go perfectly straight.

How constrained did you make it? You said that a 2" opening didn't go straight enough so that you made it a smaller opening. Did you make it as small as 1.5" or closer to 1.75"?

[Chris is me]

Originally Posted by Bstep

How constrained did you make it? You said that a 2" opening didn't go straight enough so that you made it a smaller opening. Did you make it as small as 1.5" or closer to 1.75"?

I'd have to measure to be sure, but it was pretty close to 1.625. We machined 1/2" delrin stock down, adding a taper to the loading end, and placed it on the top wall of our shooter. One stick close to the wheel side, one stick close to the wall side. The main effect was getting rid of our height variation but the curve disappeared too.