Logo XXtreme manual

[dahld]

FWIW, Kyle never has used three straps on the battery plate. Only two, and we've yet to have any packs "shift" on the plate.

Remember, as a manufacturer of a product (with all the liability attached), Mikado has to in all cases present, instruct, and display the model as safely as reasonably possible.

(-: Dave

[el guapo]

thrust bearings.

anyone notice their orientation in the manual. looks like the open end of cage is pointed outwards. I normally point the cage in wards to "hold" the grease. I've often wondered if it made a difference.

[Jays200]

Originally Posted by el guapo

thrust bearings.

anyone notice their orientation in the manual. looks like the open end of cage is pointed outwards. I normally point the cage in wards to "hold" the grease. I've often wondered if it made a difference.

That is interesting because if you zoom in to the thrusts on the tail they've done the same thing as the mains. Like you, I put mine in the other way for the same reason as you. Perhaps I've been doing wrong?

[Bullfrog98]

Originally Posted by el guapo

thrust bearings.

anyone notice their orientation in the manual. looks like the open end of cage is pointed outwards. I normally point the cage in wards to "hold" the grease. I've often wondered if it made a difference.

Good question, I do the same thing, but I would not mind some clarity on the issue.

[busterboy]

It makes sense to keep the grease in the cage, sure that must be wrong but will stand correcting.

[dahld]

I'm probably going to get some "super bearing expert" on here to say I'm full of B/S...

But, I did read in a thrust bearing spec. once, that the cage of the bearing is there to keep the balls properly oriented, spaced and in position. So...

When (improperly) installed in the way to "keep the grease in", the cage due to rotational forces is thrown away from the balls, and the balls have more opportunity to move around.

When the cage is (properly) installed as in the XXtreme's manual, the cage as it's thrown outwards traps and holds the balls in their exact orientations, the whole purpose for the cage even being there.

For many years I also installed the cage to "trap the grease", and often had the balls fallout of the cages when disassembled, and the balls often looked terrible, and the bearings needed replacing often (sometimes less than a 100 flights on the Logo 600, under hard use).

Once I started installing the cage as in the spec I read, bearing life improved dramatically, they now go for hundreds of flights, and when dissembled, the balls never fall out of the cage. Just re-grease and keep going.

Based on my experiences, I'd recommend installing them as depicted in the manual. We have yet in all of 2011 needed to replace a thrust bearing on any of the XXtremes we have. The fact they are huge (23mm in diameter) to begin with, and with the cages properly installed, they seem to be pretty bullet-proof.

Hope this helps,

Dave

[Twister773]

I, as everyone else, have installed them to "hold in the grease". I also have noticed what Dave has said about the balls falling out when it is taken apart after a while. When my X gets here Ill install it as the manual depicts. What you said makes a lot of sense Dave, but, I am no super duper bearing expert either.

[trickybit]

No expertise here. It could be true, but it's counter intuitive. My thinking would be that the bearings keep their relative spacing just fine no matter which way the cage goes.

And the force effect you describe, if significant which it may well be, would seem to press the cage against the rolling balls, instead of tending to "free" them. If I had to guess which effect would be detrimental... less containment versus more friction against the cage, I'd think the latter would be worse.

Now, perhaps by design of the cage when installed "flat side in" the outer portion of the cage rides on the outer race, and prevents the forces from impacting the balls. If true by inspection or by experts in the design, THAT I could believe is significantly good.

I've always wondered whether the effect to "keep the grease in" was meaningful.

I'm going to google around to see if we can find some expertise on the subject.

[trickybit]

Well, that was a fun google. Bearings are amazing.

Anyway, having seen a number of references, diagrams and product description of thrust ball bearings with "cages" or "retainers," there is not one mention of the orientation of the cage in the application.

What's clear is that our application is somewhat unique. Normally, a thrust load would be put onto a bearing that was more or less stationary, such as a shaft for a boat, a "lazy susan" or something like that. I didn't see anything about any applications where the lubricant was under any force like ours.

There's this interesting piece about the orthogonal pattern http://www.rctek.com/technical/beari...rust_race.html

When the shaft is spinning very fast, the bearings themselves are forced outward, and then the construction of the retainer can (apparently) make a difference. In fact, in that application, centrifugal force on the lubricant is outwards from the shaft, not along the shaft in the direction of the thrust force.

I'm to the point of betting that it doesn't matter at all...

[trickybit]

By the way, among the interesting pages I found on this search, this one has a catalog of many (full scale) rotorhead designs: http://www.b-domke.de/AviationImages/Rotorhead.html

I want this one: http://www.b-domke.de/AviationImages...ead/15007.html

[trickybit]

Originally Posted by trickybit

By the way, among the interesting pages I found on this search, this one has a catalog of many (full scale) rotorhead designs: http://www.b-domke.de/AviationImages/Rotorhead.html

I want this one: http://www.b-domke.de/AviationImages...ead/15007.html

Man, and we thought the Xxtreme head was beefy. Yeesh!

[Jays200]

Originally Posted by Twister773

I, as everyone else, have installed them to "hold in the grease". I also have noticed what Dave has said about the balls falling out when it is taken apart after a while. When my X gets here Ill install it as the manual depicts. What you said makes a lot of sense Dave, but, I am no super duper bearing expert either.

I'm with you on this one too, Twister. I've had the balls fall out and have nothing to lose and everything to gain from trying it cage out as Dave has mentioned. There's next to no grease in my thrusts when I take them out anyway with the cage in.

Mikado should mention "cage out" in the manual the same way they mention "larger hole in" for the thrust bearing sides.

Never stop learning stuff on this forum.

Thanks for that Dave.

Cheers,

Jays