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Acrolithe
Apprentice
Joined: 15 Dec 2006
Posts: 51
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 Posted: Thu Jan 04, 2007 2:14 am Post subject: Bearings |
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I need to figure out a bearing solution for a turbine engine. I get about 30 seconds of runtime with silicon lube before it eats the axle. Then it starts to wobble until it ruins the blades. From there, things really start to go haywire. Breaking apart, etc.
But when you fire it initially, I wouldn't be surprised if I was getting 25000 rpms. So the wear rate is incredible. |
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4x4crawler
Moderator
Joined: 07 May 2005
Posts: 655
Location: Oshkosh, WI, Earth , United States
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| Posted: Thu Jan 04, 2007 5:55 am Post subject: |
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The diameter of an axle is 3/16". Here
You may also want to search for an RC thrust bearing solution. |
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Acrolithe
Apprentice
Joined: 15 Dec 2006
Posts: 51
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| Posted: Thu Jan 04, 2007 7:44 am Post subject: |
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| Well damn. I'm going to have to mill it anyway. Maybe I should just make an aluminum axle well I'm at it... |
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Acrolithe
Apprentice
Joined: 15 Dec 2006
Posts: 51
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| Posted: Thu Jan 04, 2007 7:57 am Post subject: |
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| wait. What about a 3/16 OD split bearing. Lathing down the axle would be easier than making a fixture to hold my engine in a vise. |
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4x4crawler
Moderator
Joined: 07 May 2005
Posts: 655
Location: Oshkosh, WI, Earth , United States
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| Posted: Thu Jan 04, 2007 2:10 pm Post subject: |
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| A bearing that small won't be very durable, but I'm not sure how much that matters, considering we're talking about plastic bricks. |
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weaselman
Apprentice
Joined: 26 Jul 2005
Posts: 100
Location: USA
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| Posted: Thu Jan 04, 2007 7:44 pm Post subject: |
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| 4x4crawler wrote: |
| A bearing that small won't be very durable, but I'm not sure how much that matters, considering we're talking about plastic bricks. |
Actually those bearings are very durable becuz if you think about it most of those R\C cars go about 50-70mph and those look like wheel bearings so those would have to be pretty tough...
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michaelwitherspoon
Moderator
Joined: 14 Mar 2005
Posts: 336
Location: wa, usa
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| Posted: Thu Jan 04, 2007 8:09 pm Post subject: hmmm |
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Double up the support on the axle it should wear a lot slower. I never use bearings and using an electric motor tachometer it says its going 50-100,000 rpm. The only time I've ever experienced wear was when the axle wasnt supported enough and the axle had just enough room to bounce around.
mike
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pehrlich
Apprentice
Joined: 12 Jun 2006
Posts: 138
Location: GMT -5
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| Posted: Thu Jan 04, 2007 10:25 pm Post subject: |
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| Best yet would be an OD of 6mm, ie, diameter of the thickest part of a technic pin. That way you only have to drill the brick a little, and the axle not as much. |
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Acrolithe
Apprentice
Joined: 15 Dec 2006
Posts: 51
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| Posted: Fri Jan 05, 2007 4:04 am Post subject: |
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Ok, guys. How do I post pictures of this damn thing?
Doubling the size of the the axle support hasn't seemed to help very much. The axle is far softer than the bricks.
I DID try the white axles, though. It is a different material. And it IS much more resistant to wear. But it still won't last more than 2 minutes.
I'm thinking that changing the angle of the intake to augment a more laminar flow pattern will reduce sideload on the blade assembly and reduce wear on the axle. That, and using a filler element around the blades, so I can boost effiency and torque while dropping pressure. |
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