Teflon washers and Inox thrust bearing high speed

[Alfa Spirit]

Hello guys,
I will test the Speedmaster with a high quality thrust bearing, this one can take 45000 RPM, what do you think? I' m surprised, nobody use those high quality high speed thrust bearings

[martin]

Ive use this type of thrust bearing on my ic tethered hydros for 40 years but we dont use flexes we use wire drives where theirs no wind up or shortening like you get with flexes. Problem with a flex running against these thrust bearings is having the gap between the dog & thrust right as the flex shortens at different lengths depending on the load at diff rpm & on what props are putting more load on the flex. If the gap you leave is to little the dog bottoms against the thrust whilst the flex hasnt reached full wind up & you can end up breaking the flex.Opposite effect if the gap is to large the dog dosnt make contact with the thrust. Would work well though on the 2 piece flex & separate stub as theirs no shortening of the gap left & the stub justs floats in the strut.

[Fluid]

Martin has it going on. Taking the thrust at the strut is a poor idea for the reasons above. Too, a ball bearing does not operate well in water and will pit quickly, destroying the bearing's ability to transfer thrust with minimal drag; a bad idea for normal use. Instead take the thrust at the motor/mount where it is dry and you don't have to worry about cable windup. Or simply take the thrust on a motor bearing as originally intended by the motor maker.


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[Alfa Spirit]

I understand but this thrust bearing, the 2 bb washers are sealed around the shaft, washers and balls can' t move.

[Rumdog]

Sooooooo?

[Fluid]

I understand....

Apparently you do not. A thrust bearing only works if there is thrust applied to both sides, otherwise it is just an expensive decoration. This is tough to do taking the thrust at the strut; it's either no contact, or the flex cable is trapped between the motor and thrust bearings, increasing friction a lot and stressing the cable. It doesn't matter if the balls are trapped or not. Good luck with your project.



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[Alfa Spirit]

Yes, I understand but the flex shaft is short and high quality from UK. Lenght is 15cm / 6", the CC1717 is near the back of the hull

[dana]

It's pretty, and completely useless IMO. There is a reason this isn't being done.

[Rumdog]

completely useless.

[carlcisneros]

that flex shaft no matter how short WILL STILL SHRINK (if you will) under load...............
good luck