thrust bearing.....what's your take?

[tlandauer]

I can't believe somebody drug this back up, it was a awsome thread but it's been beat to death

My sentiments exactly!
However, I can't agree more with Travis' latest post.

[tlandauer]

Yeah it is something I have played at too but I don't like the fact that there may be some play in square drive....that's just me.
I now use a brazed continuous shaft for ease of maintenance like to OSE ones

I don't like that either, but if cost is not a factor, i guess we can have a cable with brazed stub shaft which is then machined into a square and then mated to a square drive, then everything is precision machined, any play will be kept minimum.

[flraptor07]

Reason: nowhere have I seen anyone provide a factual measurement for the shrinkage of a flex shaft under load.

I would think there are lots of variables, like length of shaft, Dia. of shaft, brand of shaft, and or Manufacturer of bulk cable, ETC. I could keep going. I once had a shaft that was about 13" long that I could get one full prop revolution before the motor would turn. I replaced it with a shaft from the same place that would turn the motor instantly. So I'm thinking it would be pretty tough to get accurate testing on these flexes with those kind of inconsistancies.

[SlickZERO]

If there is no thrust bearing wouldn't the armature be pushed back against its bearings? How could it float and center itself?

heres my 2 cents..if a motor has fore and aft paly in it..you don't want to put a thrust washer on to the point where it takes all of the play out of it..the motor should be free to center itself in the magnetic field..yes.maybe that means a bigger gap in strut..but it should be free to at least stay at point where it rests if you pull or push on it ant it returns..

[kfxguy]

If there is no thrust bearing wouldn't the armature be pushed back against its bearings? How could it float and center itself?

Lol, very good point!

[ray schrauwen]

When I get some H&M cable soon, I will show you the difference between it and all the rest. IMO it is superior quality with less compression than any other.

[kfxguy]

When I get some H&M cable soon, I will show you the difference between it and all the rest. IMO it is superior quality with less compression than any other.

Do they have .187? Where can I get it from?

[iop65]

Do they have .187? Where can I get it from?

yes

don't they ship to usa?

rcraceboats .de sells the h&m flex and collets too

[ray schrauwen]

It's just raw cable, no stub. Brian at Rocket City Racing can get it for you but, it may take a little while. I am getting some 0.130 cable from him to loctite into 3/16 stubs.

Do they have .187? Where can I get it from?

[crispyspa]

Reason its not needed in aircraft application is the frce is the opposite direction, forcing the motor tohold together.

I think you may have that backwards.
The "c" clip is what holds the motor together under thrust. I improperly seated the "c" clip one time and when I hit the throttle the prop and the rotor took off leaving the stator and the airboat behind.

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I use a thrust bearing on the strut of my blackjack 29, but I also leave a bit of a gap, That way, (at least in my mind) I can distribute the points of thrust between the motor and the strut under heavy load and at speed most of the thrust is at the motor. Whether it's actually happening that way is anyone's guess.

[angrycat]

...

[Jeff Wohlt]

I rebuilt many hot brushed plettenbergs in the old days. We would eat rear shims and bearings and replace them....what made this happen? We started using thrust bearings at the motor and this took care of virtually all of that issue...we just burned cells and brushes after that....LOL. We were running mainly Hydros....UL-1 From RC Hydros. I even had the molds for some time and built several glass versions. We changed from 700 motors in one class and then shove pletts in them for another class....12 round cells.

[dmitry100]

Ok, so if you have a Mystic with motors mounted close to the rear transom with super short flex cables... would you technically not use a gap at the stingers and drive dog at all (besides the teflon washer)?

And what determines the strength of flex cable... the less flex there is in the cable the stronger it is from what I'm hearing?

[dmitry100]

kfxguy: Are you using a 3/16 shaft for your flexs? I have some bare 5mm Flex cable from Gundert coming any day now incase you wanted some... It's apparently really strong. I was planning to sand the entire cable down to 4.75mm (this is normally done when attaching a shaft for 4.75mm)

[flraptor07]

Ok, so if you have a Mystic with motors mounted close to the rear transom with super short flex cables... would you technically not use a gap at the stingers and drive dog at all (besides the teflon washer)?

And what determines the strength of flex cable... the less flex there is in the cable the stronger it is from what I'm hearing?

I would think that the shorter the flex the less gap you need. But how much is anybody's guess because of all the different cables out there, one determining factor I use is when I get my flex cut to the length I'm going to use. I twist the cable by hand in the direction of rotation and see how much wind up I can get and start from there. you may have to adjust it a couple times. IMO there is no set gap setting, it all depends on the cable length, Brand, Dia., Etc. There is a rule of thumb that most go by but that's not nessasarily what it really needs. Again this is just my opinion and it works for me.