Andymark Pneumatic wheel problems

[PizzaBoxZombie]

As several other teams and IR3 have shown in various youtube videos, the pneumatic wheels from andymark are pretty decent shooting wheels. after recieving ours, however, we found that ours are out of balance/round. spinning at 5-6500 rpm they shake around a lot and can not achieve full potential speed.
we have since changed wheels for some more consistent and faster, but we were wondering if anyone else had tried to use them and found the same problems? and if anyone has, have you found a solution?

[Mk.32]

We definitely have had the same issues, we haven't found a solution and moved on to other options.

[GUI]

Is the tire bead seated correctly?

[ehochstein]

Originally Posted by GUI

Is the tire bead seated correctly?

That's the problem. We can't get it to seat correctly. Any tips/tricks to do so?

[PizzaBoxZombie]

Originally Posted by GUI

Is the tire bead seated correctly?

yeah, ours were, to the best we could figure out, ill double check. thanks. the other problem was we still had to balance the valve stem.

[Tyfighter98]

I believe I was experiencing that same problem today when we were testing a prototype. The pneumatic wheels appeared to have a lot of free movement. I don't know if this is just our prototype or wether the wheel isn't seated properly.

[wilsonmw04]

I believe the problem is with your speed and not the wheels. If I remember correctly, IR3 only used a cim at ~55% power.

[bEdhEd]

Originally Posted by PizzaBoxZombie

yeah, ours were, to the best we could figure out, ill double check. thanks. the other problem was we still had to balance the valve stem.

Is there a special method in order to seat the wheel?

[Ether]

Originally Posted by wilsonmw04

If I remember correctly, IR3 only used a cim at ~55% power.

I'm trying to hunt down the source for this. Do you remember where you got it?

[Ian Curtis]

Originally Posted by PizzaBoxZombie

As several other teams and IR3 have shown in various youtube videos, the pneumatic wheels from andymark are pretty decent shooting wheels. after recieving ours, however, we found that ours are out of balance/round. spinning at 5-6500 rpm they shake around a lot and can not achieve full potential speed.

I doubt Andy & Mark expected teams to try and go 125 mph with those wheels. As others have said slowing down or switching is probably the least work per performance.

[ehochstein]

Originally Posted by Ether

I'm trying to hunt down the source for this. Do you remember where you got it?

We tested our pneumatic wheel at 60% speed today, launching between the wheel and our wood prototype base. We experienced approximately the same range/speed as the Robot in Three Days robot.

[Andrew Zeller]

Originally Posted by Wiifi

We tested our pneumatic wheel at 60% speed today, launching between the wheel and our wood prototype base. We experienced approximately the same range/speed as the Robot in Three Days robot.

60% of CIM free speed?

[Oldbikerider]

On a related question, does anyone know what the safe working speed is with the AndyMark wheels? I've searched but can't find anything. I'm thinking that some bursting strength calculations are necessary here.

We've been testing with some 10 inch OD "highway" treaded mobility scooter tires mounted on 4 inch go-kart wheels. At 1600rpm there is significant tread growth and they start to get unstable in balance. The two wheels also appear to feed vibrations to each other in complex ways.

I wonder what actually fails first. Would the tire tread just catastrophically fail, or would bits start shedding more gently? I suspect the former.

Graham.

[Kyle Love]

Just to bring up a couple of other possible issues...

Are the bearings installed properly (with flanges and such extremely level and tightly in place)?

Are you using a cantilevered or secured method for the wheel?

I would guess that if you could have a bearing or some other type of "reciever" for the end of the shaft, you may take some of the wiggle out of it. I do agree with some posts above that I doubt these wheels are really meant to spin as fast as many teams are spinning them. More then likely, that is the main issue, but I wanted to just bring up a couple of other possible issues.

[ehochstein]

Originally Posted by boarder3512

60% of CIM free speed?

I can't promise that, we coded eleven buttons to control the speed. Button 1 was 10%, 2 -> 20% etc. We ran it on buttons 6 and 7.

I uploaded a video of our shooter at 1000 frames/sec http://youtu.be/7dN1thFqr7k