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-   -   Team 3992 Launcher - Help w/ Vibration? (http://www.chiefdelphi.com/forums/showthread.php?t=111655)

ksafin 20-01-2013 00:24

Team 3992 Launcher - Help w/ Vibration?
 
Hello all.

We just recently got our launcher working to the distance and height we'd like:
http://www.youtube.com/watch?v=RWVur...ature=youtu.be

However, as you can see, there's IMMENSE vibration which is moving the frame and keeping us from being consistent.

Any suggestions? Some issues we think may be causing this:

1) Pneumatic wheels aren't true (even) they have some kind of wobble to them.
2) No bearing/support at the top of the shafts for the wheels

Thoughts? Suggestions?

Alan Anderson 20-01-2013 00:43

Re: Team 3992 Launcher - Help w/ Vibration?
 
Quote:

Originally Posted by ksafin (Post 1218931)
1) Pneumatic wheels aren't true (even) they have some kind of wobble to them.

You'll need to balance them. A heavy bolt or two through the hub, opposite the valve stem, might be a good start.

Andrew Zeller 20-01-2013 00:43

Re: Team 3992 Launcher - Help w/ Vibration?
 
Awesome prototype! How far away from the shooter is that wall?

How accurate does it shoot at close range?

What speed are you running the pneumatic wheels at?

I agree with your suggestions about the lack of support causing vibrations.

This video gives some suggestions about balancing pneumatic wheels:
http://www.youtube.com/watch?v=88Ik-...82A9A16DE04FCB

ksafin 20-01-2013 00:47

Re: Team 3992 Launcher - Help w/ Vibration?
 
Quote:

Originally Posted by Alan Anderson (Post 1218940)
You'll need to balance them. A heavy bolt or two through the hub, opposite the valve stem, might be a good start.

Does it also have to be inflated all the way to 36 psi? Like, will any less than essentially maximally full cause unbalance?

I saw the Lunch with Andy episode and will do that though; does it have that significant of an effect?

Quote:

Originally Posted by Andrew Zeller (Post 1218940)
Awesome prototype! How far away from the shooter is that wall?

How accurate does it shoot at close range?

What speed are you running the pneumatic wheels at?

I agree with your suggestions about the lack of support causing vibrations.

This video gives some suggestions about balancing pneumatic wheels:
http://www.youtube.com/watch?v=88Ik-...82A9A16DE04FCB

The wall is about 50 ft from the shooter, and the frisbees hit above 20 ft in the air (the lamps are hanging at about 21 ft).

We never tested close range; this was a test on friday night and we haven't been back since.

We're running them 1:1 on CIMs.

F22Rapture 20-01-2013 10:27

Re: Team 3992 Launcher - Help w/ Vibration?
 
It might be a good idea to mount the wheels on gearboxes (such as the upcoming SpinBox) rather than direct-drive. The CIMs don't have much internal structure to prevent vibration.

MrForbes 20-01-2013 10:29

Re: Team 3992 Launcher - Help w/ Vibration?
 
Quote:

Originally Posted by ksafin (Post 1218945)
I saw the Lunch with Andy episode and will do that though; does it have that significant of an effect?

It sure does, especially at high speeds. And if it's balanced properly, you might be able to let most of the air out, and this will allow you to have the wheel compressed more on the Frisbee, giving better performance (because it gets more friction).

Ian Curtis 20-01-2013 15:06

Re: Team 3992 Launcher - Help w/ Vibration?
 
Quote:

Originally Posted by ksafin (Post 1218945)
I saw the Lunch with Andy episode and will do that though; does it have that significant of an effect?

This is my favorite demonstration of why you need to balance things that are going to spin fast.

jkessler_22 05-02-2013 12:47

Re: Team 3992 Launcher - Help w/ Vibration?
 
Quote:

Originally Posted by ksafin (Post 1218931)
Hello all.

We just recently got our launcher working to the distance and height we'd like:
http://www.youtube.com/watch?v=RWVur...ature=youtu.be

However, as you can see, there's IMMENSE vibration which is moving the frame and keeping us from being consistent.

Any suggestions? Some issues we think may be causing this:

1) Pneumatic wheels aren't true (even) they have some kind of wobble to them.
2) No bearing/support at the top of the shafts for the wheels

Thoughts? Suggestions?

We have had good success by placing 0.75 oz of stick-on weights (Harbor Freight or other places sell them) in the open space on the plastic wheel hub , directly across from the valve stem. It made quite a difference without doing anything else.

RonnieS 05-02-2013 13:02

Re: Team 3992 Launcher - Help w/ Vibration?
 
We had the same problem when making our shooter. I would greatly consider connecting your motor(s) and wheels together with a chain or belt via sprocket or pulley. It greatly reduced ours because the belt took away a lot and then we looked to extra bracing. Balancing the tire was the last thing we did. Hope this helps.

Bob Steele 05-02-2013 16:29

Re: Team 3992 Launcher - Help w/ Vibration?
 
Quote:

Originally Posted by jkessler_22 (Post 1228034)
We have had good success by placing 0.75 oz of stick-on weights (Harbor Freight or other places sell them) in the open space on the plastic wheel hub , directly across from the valve stem. It made quite a difference without doing anything else.

Just make sure that they stay stuck on at speed. I would think you would need a mechanical fastener or over time the glue will creep and you will have a projectile...

jkessler_22 07-02-2013 09:04

Re: Team 3992 Launcher - Help w/ Vibration?
 
Quote:

Originally Posted by Bob Steele (Post 1228235)
Just make sure that they stay stuck on at speed. I would think you would need a mechanical fastener or over time the glue will creep and you will have a projectile...

The pneumatic tire hubs have a pocket (void) where the weights with sticky tape can be placed. The spinning wheel just forces the weights against the inner part of the hub, further securing the weights. There is no glue involved, just the stick-on weights used to balance car tires.


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