Main shaft bearing play help

[vtown nick]

So I rebuilt my 500 after crashing it last month. I went with the 1 piece helioption main shaft thrusted bearing setup. So far I'm less than happy with the money I spent and wishing I had stuck with stock.

The directions don't tell you which way to face the thrust bearing itself like align manuals do with the feathering shaft thrust bearings. I see the races are labeled and those I know where to put just not the actual bearing itself.

Secondly are these supposed to be preloaded with shims or do you just get it not loose but not tight?

I contacted them and the lady helping me didn't even seem to know any of the questions I asked and it was pretty frustrating.

I put the first flight on it tonight and it has major cyclic shakes. Side to side forward and back as the head speed comes up, once I get around 70% the shakes are mostly gone then come back a little around 100% but not too bad. I dropped my elevator gain down a tad and it seems better. As it is on the ground it dances all over the place spooling down when I land and on take off its all over the place.

I can grab the head or the main shaft with no head and move the main shaft within the bearings in all directions other than up and down. There is no up and down just side to side. With the stock bearings it did this also but not as much.

Any input would be greatly appreciated!!!

[TR450ZS]

Hey sorry to hear you having problems with that bearing block. Mine is solid and smooth. Did you receive the build diagram with your block? It shows quite clearly which way the bearings go in. Basically, you drop the radial bearing into the block (I added a small smear of bearing retainer to the outer race). Then drop the inner thrust washer ( as per the diagram, the 2 washers are not the same size), then the bearing cage then the top washer. Note the top and bottom face orientation of the washers.Then lock down with the top plate secured with the 4 little bolts supplied (with a dab of loctite). Test fit the mainshaft into the assembly with main gear fastened, and check for up and down play. Add shims if needed.
By the way, are you dead certain you have the correct bearing block for your heli?

[Digger1973]

The only time I get lateral play in bearings are if the bearings are bad or very cheap. No play at all in my new bearings yet. Hope they stay that way for atleast 150 flights.

[vtown nick]

Originally Posted by TR450ZS

Hey sorry to hear you having problems with that bearing block. Mine is solid and smooth. Did you receive the build diagram with your block? It shows quite clearly which way the bearings go in. Basically, you drop the radial bearing into the block (I added a small smear of bearing retainer to the outer race). Then drop the inner thrust washer ( as per the diagram, the 2 washers are not the same size), then the bearing cage then the top washer. Note the top and bottom face orientation of the washers.Then lock down with the top plate secured with the 4 little bolts supplied (with a dab of loctite). Test fit the mainshaft into the assembly with main gear fastened, and check for up and down play. Add shims if needed.
By the way, are you dead certain you have the correct bearing block for your heli?

I understand the race/washer layout quite clearly it's the actual orientation of the thrust bearing/cage that I wasn't sure up or down it should go.

I made sure the part number was for the pro and it would have not fit if it was for the other models. I'm running a flybar mainshaft but it is for a pro so I don't see that being an issue. Just odd the main shaft doesn't fit tight into the bearings.

I have battled this on my 450 and several align main bearings later I gave up and just fly it. I just had hoped the 500 would be tighter tolerances being larger parts. Trying to narrow down my vibe issue as best as I can.

[Xrayted]

There can be no movement side to side of the main shaft. That is going to wobble itself to death in flight and the bearings will eventually be hogged out and fail because of it.

As bad as it sounds, you may want to just walk aways from this so called upgrade and get the proper parts back in. NO standard RC heli "needs" thrust bearings on the main shaft! They are used only in very large, heavy lift commercial applications. It is a gimmick upgrade solution looking for a problem to solve that doesn't exist, and does nothing but make the assembly more complicated with more bearings that will need to be replaced in a crash, or fail and start vibrations in flight.

There are no helis just falling out of the air because their main shaft radial bearings failed in flight from lateral loads on them, so the addition of thrust bearings isn't doing anything at all. The other option is to purchase higher quality radial bearings so the main shaft fitment is as it should be. It sounds like they are using very low ABEC rated bearings in this upgrade part and there is too much play between the shaft and the bearing races, or the outer races aren't fitting in the bearing holders very well.

[Digger1973]

My G20 gasser had thrust bearings on the main shaft. Their entire purpose was to take the heavy load of an inverted gasser off the radials. In that capacity it helped but out 500's are light and the radials are good enough. My stock bearings lasted 155 flights with high pitch manouvers so I would just put the stock blocks back in and be happy.

[vtown nick]

Originally Posted by Xrayted

There can be no movement side to side of the main shaft. That is going to wobble itself to death in flight and the bearings will eventually be hogged out and fail because of it.

As bad as it sounds, you may want to just walk aways from this so called upgrade and get the proper parts back in. NO standard RC heli needs thrust bearings on the main shaft! They are used only in very large, heavy lift commercial applications. It is a gimmick upgrade solution looking for a problem to solve that doesn't exist, and does nothing but make the assembly more complicated with more bearings that will need to be replaced in a crash, or fail and start vibrations in flight.

There are no helis just falling out of the air because their main shaft radial bearings failed in flight from lateral loads on them, so the addition of thrust bearings isn't doing anything at all. The other option is to purchase higher quality radial bearings so the main shaft fitment is as it should be. It sounds like they are using very low ABEC rated bearings in this upgrade part and there is too much play between the shaft and the bearing races, or the outer races aren't fitting in the bearing holders very well.

This was a fear of mine after assembling it. I should just get some high quality abec bearings for my stock blocks then it looks like? I wasn't really thrilled about the thrust bearings just the fact that it was a one piece block but so far it is a joke.

I just put 4 packs through it tuning the iKON and not making much head way. When I first converted this heli to fbl it had about 25 flights since building no crashes and with the basic 500 settings it had a pretty bad elevator bob in stationary hover, it would get aileron shakes on descend too till I tuned it a bit. This time around the basic 500 settings it has mega fast aileron oscillations in a hover that never really go away untill I load up the head, the elevator axis is very nice and so is my tail with super high tail gain. On spool up at a certain rpm coming up to headspeed it would do a violent aileron shake till it passes this speed, in a hover that is.

I've never experienced this with my other iKON units or 3gx on my 450's and 250's so I'm kind of scratching my head. My main blade grips feel notchy but they did from day one, you can slowly move them with no links attached and feel ever ball move around the race, something I would assume should not feel like. All the proper washers and bearings are in place as per the manual, my 450 is smoother than this but is half the size so I'm not sure if the 500 head is just that much tighter?

[Gladius]

I put the i2rc bearing blocks in my 500. The bearings are larger and more robust, plus they use ABEC-7 bearings, so the tolerances are tighter. My main shaft used to have a little play with the stock bearings, but there is none with the i2rc bearings. Finally, their bearings come with a warrantee, so you can get them replaced at any time - you just need to send them the old bearings.

[vtown nick]

Originally Posted by Gladius

I put the i2rc bearing blocks in my 500. The bearings are larger and more robust, plus they use ABEC-7 bearings, so the tolerances are tighter. My main shaft used to have a little play with the stock bearings, but there is none with the i2rc bearings. Finally, their bearings come with a warrantee, so you can get them replaced at any time - you just need to send them the old bearings.

That brand slipped my mind this morning. I read nothing but praise from their products. I know what is on my wish list now!

Thanks