Re: Plaction wheel shooter?
 

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.

Re: Plaction wheel shooter?
 

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.

Re: Plaction wheel shooter?
 

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.

Re: Plaction wheel shooter?
 

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.

Re: Plaction wheel shooter?
 

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.

Re: Plaction wheel shooter?
 

Our team has always used double stick tape, instead of adhesive and then revit the tread to the wheel. Have never lost a tread, even when all the side wall of the plaction was all broke off.