Plaction wheel shooter?

Hello,

My team is a bit behind schedule, and we have not finished our shooter yet.

We meant to use 8" AM pneumatic wheels directly driven from cim motors, but that caused very strong vibrations, which we didn’t like.

We tested the same setup with 8" AM Plaction wheels and the vibration was considerably lower.

We would like to use the plaction wheels, but I’m afraid that they won’t work as well as pneumatic wheels, and we won’t be able to test for a few more days.

So… has anyone seen, used, tested or heard of an 8" plaction wheel shooter?
I’d like to try and gain some 2nd hand experience here in order to make the better decision early on.

Thanks,
-Leav

We are running 6" performance wheels from am and are having good results with it (not half court shots, but we can score reliably). I’d assume that you’d see similar results with 8’’ plactions.

we used an 8 in plaction in our first round shooter test and it worked really well. we could make shoots consistently from the sides of the pyramid and behind it.

You could try balancing the wheel as Andy talked about. And spin them a little slower, with both ends of the shaft supported.

My team has done extensive prototyping in shooters this year. Although we haven’t prototyped an 8 inch plaction wheel shooter we have messed around with other 6-8 inch “hard” (non-pneumatic) wheels. Through our observations it seems that you have to have some sort of give in the system (other than in the frisbee). When using pneumatic wheels the give is in the wheel. When using harder wheels you have to have give in the wall opposite your shooter. My team achieved this using a strip of pool noodle cut to a rectanglar cross-section of about 3/8 x 2 inches.

Our team was using a Plaction wheel until the tread separated at the stapled connection and gave one of the mentors a pretty nasty “rug burn”. We went to the pneumatic wheels and balanced them initially by adding 0.75 oz of automotive stick-on weights (Harbor Freight has them) to the opening in the hub directly across from the valve. That seemed to work much more smoothly, but we will probably try to fine tune the balance before competition.

We are using 8" FIRST rubber wheels with added on belting, and these work great. It was not much different than the pneumatic wheels as far as distance goes. We also mount them low on the frisbee.

Alex,
What belting are you using, and how did you mount it to the wheel? We might want to do something similar, but I’m wondering about the safety issues that others have mentioned (tread tearing off at high speed). What is the highest RPM you have tested with this belting?

just make sure the plaction tread is on correctly if not the tread can fly off and hit you like it happened to me and leave a nice mark

Luke,
Did you find a way to install the plaction tread “correctly”?

Correct == Safe && Effective

We’re using AndyMark’s pneumatic wheel and found it works well without the innertube and it doesn’t require balancing.

We’re using 8" plactions and are doing quite well with them. Our controls group has been using our prototype to gather some data as we haven’t received our machined shooter parts yet. We’ve been shooting pretty accurately and distance wise, they’re good.

We are using a 6" performance wheel with the wedgetop tread and its pretty good. we can shoot half court reliably. also we riveted the tread on. there’s no vibrations, and its super quiet.

We made a prototype shooter using an 8 inch plaction wheel a few weeks ago.

We have slow-mo video available here: http://www.youtube.com/user/EagleForce2073/videos?view=0

We have changed our shooter design, but the plaction wheel worked fairly well.

Where exactly did you add the weights?

When you say opening across from the valve stem, does that mean on top of the hub, or in between the spokes?

My team made our prototype shooter with plaction wheels, and then switched over to the AM pneumatic wheels. The plactions work fine for short to mid range shooting, depending on how you use them.

Cal,

We use the wedgetop from AndyMark (as it’s already cut into a straight 1" strip) and drill and rivet to the wheel over a 3" interval. We normally use these on our drivetrain.

We are currently spinning them at roughly 4000 rpm, without any separation.

Thanks for the answer, Alex. Our shooter has a top speed of 6000 rpm. [Not sure we need to go quite that fast, but if the motors can, we’d better make sure it’s safe.] If we change to plaction and use your riveting method, we’ll make sure to carefully test up to full speed. I’d be worried about the centrifugal force focused on the relatively small area of rivets.

Has anyone tried some kind of glue for holding the tread on the wheel at high speeds? Then all the centrifugal force is spread along the entire circumference of the wheel. Repair and replacement might be difficult, and I’d still be a little concerned about the disc contacting the ends of the tread (that may focus a little more shear force there). If anyone has experience (good or bad) with that, I’d like to hear about it and learn from you.

We placed them between the plastic spokes. The opening was fairly generous for the size of the weights. The weights I had were about 0.75" x 1.0 " and weighed 0.5 oz each. I cut one in half, stuck it to the top of another full 0.5 oz weight, then put them between the spokes.

To determine how far out of balance they were initially, we put an 8 mm shaft through our hub and supported it with two metal 12 inch rulers on edge. If we rotated the tire so that the valve was ‘up’, it quickly spun so that the valve was ‘down’. We added one 0.5 oz weight, which made it spin much more slowly, but still settled into a valve ‘down’ position. We played with the amount of weight to find a point where the wheel could be placed in virtually any rotational position and it would stay there. That weight came out to be a total of 0.75 oz in our case, but could differ depending on what wheel/tire combination you are using.

The decrease in vibration was dramatic when we were done.

Be careful with some adhesives on the plaction wheels as they could break the wheels with the wrong chemical combination. In particular, Loctite will crack plactions fairly quickly.