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Post by madpatty on Jun 22, 2014 3:17:44 GMT -5
Hi Racket,
Needed some details on the bronze cup arrangement you used in one of your engines..... How did you preload the bearings and what bearings you used? (if i am not wrong the spring was between the cups touching their OD and pushing the bronze cups against each other) What changes you went for in your skuld 666 engine regarding te preloading..
Do the pair of hybrid angular contact bearings on each end of the shaft also need any spring pre load??
Thanks Patty
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Post by racket on Jun 22, 2014 3:56:42 GMT -5
Hi Patty .
Preload by spring, either wave washer or coil spring , I've tried both types.
Bearings have been either , C3 standard with steel balls , modified with full compliment steel balls , full compliment with SiN balls , or used Allison 250 #8 engine bearings.
Preload was on the "base" of the cup towards the centre , the outer portion of the base was used to set the "endfloat" in the cup pocket in the bearing housing .
I've never used angular contact bearings .
SKULD 666 bearings will be brass bush so no preload required............ if I ever get around to finishing the engine .
Cheers John
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Post by madpatty on Jun 22, 2014 4:25:54 GMT -5
Preload was on the "base" of the cup towards the centre , the outer portion of the base was used to set the "endfloat" in the cup pocket in the bearing housing .
How towards the centre?? Weren't the spring pushing both the cups outwards towards compressor and turbine??
"Endfloat" can you elaborate please?
Thanks, Patty
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Post by racket on Jun 22, 2014 18:07:14 GMT -5
Hi Patty
Spring bearing on a smaller radius of the cup base than the endfloat step .
Yes , springs forcing towards comp and turb wheels .
Endfloat ............the shaft could be moved axially a small amount before one or other of the cups contacted the bearing housing.
Cheers John
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Post by madpatty on Jun 22, 2014 21:25:54 GMT -5
Thanks Racket, That was exactly what i was thinking....
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Post by madpatty on Jun 22, 2014 23:48:32 GMT -5
Hi John,
Can you suggest me a suitable axial turbine wheel for compressor with:- Inducer- 71mm Exducer-105mm
According to calculations it is to flow 60lbs/min.
Tried searching on net but didn't got suitable results. In the kamps book i had that page mis printed where general calculations are available...
You may also provide any general formula for the turbine wheel diameter wrt the compressor diameter.....
Thanks, Patty
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Post by racket on Jun 23, 2014 0:17:04 GMT -5
Hi Patty
Generally an axial turbine wheel ~90% of the compressor diameter , so ~95mm minimum up to maybe 100mm maximum .
Axial wheels are not easy to come by, ......no suggestions for that size :-( ..............thats why we use the standard turbocharger turbine wheel .
Cheers John
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Salvatore
Member
Joined: April 2013
Posts: 12
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Post by Salvatore on Jun 23, 2014 5:05:41 GMT -5
Hi Patty,
Here you will find lhttp://italian.turbine-wheel.com/sell-inconel718_yltw_145_axial_turbine_wheel_with_high_temperature_resistance-11877.htmle axial turbines of various sizes.
savior
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miuge
Veteran Member
Joined: March 2014
Posts: 199
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Post by miuge on Jun 23, 2014 6:04:05 GMT -5
There's also few manufacturers selling their axial turbine wheels at alibaba.com. Ask if some of them could sell you a sample
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Post by madpatty on Jun 23, 2014 11:34:43 GMT -5
Hi Racket,
Today i managed to somehow remove the balls out of a riveted cage SKF ball bearing....was a royal pain in the ass..
How to convert that bearing into a all ball no cage(complement arrangement).....i have ordered some ceramic balls of same size as steel balls....
Thanks, Patty
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Post by racket on Jun 23, 2014 18:41:53 GMT -5
Hi Patty
To remove balls from the bearing you sometimes need to heat the outer ring once the cage is disassembled .
You need to fit the inner raceway onto a mandril in your lathe and turn/grind off most of one lip making sure you don't mark the running surface for the balls .
Cheers John
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Post by madpatty on Jun 23, 2014 20:24:42 GMT -5
Thanks Racket,
I can do that but won't the balls or the bearing get damaged because the balls wanting to come out from that ground lip while the bearing is running..?
Thanks, Patty
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Post by racket on Jun 23, 2014 21:31:38 GMT -5
Hi Patty
You need to orientate the bearing so that the preload keeps the outer raceway in contact with the balls that are in turn, in contact with the unaltered side of the inner raceway , an angular contact bearing is a "one way" bearing. Cheers John
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Post by madpatty on Jun 23, 2014 21:37:04 GMT -5
Thanks Racket,
But the bearings i will be making full compliment arrangement of are Radial Deep Groove bearings(not angular contact).... Do the whole same process goes for Radial bearings also?
Thanks, Patty
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Post by racket on Jun 24, 2014 1:07:17 GMT -5
Hi Patty
To make them full compliment you need to grind off one shoulder of the inner raceway otherwise you can't get all the balls in to make it full compliment , once a shoulder is ground off then the deep groove ball race has to become an angular contact with a "one direct" installation so that the thrust loads keep the balls in contact with the intact shoulder on the inner raceway .
A normal deep groove ball race can generally be fitted either way as they are the same on both sides .
Cheers John
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