Main grip thrust bearings order.

[smittylube]

I have been flying logo helis for many years. Recently I've been impressed with Matts synergy heads and the hole to lube the thrust bearings.

I've also noticed the synergy and the protos heads have the thrust bearing in between the radial bearings.
I was thinking of changing the order on my logo grips as well drilling a small hole to allow it to be greased without removal.

Another thing I thought about is it probably throws less grease out as well with a radial bearing there to stop it, or at least slow it down. And less dirt can get into the thrust bearing since it has to go past the radials to get there.

It also seems to me that the radials being spaced out further have more leverage as well to stay centered.

The only obvious thing I can think of that needs to be different would be a smaller diameter washer between the thrust bearing and outer radial bearing that allows clearance and contacts the inner race only, and the washer at the bolt contacting the inner race of the radial bearing only. (Logo 600 head)

Am I missing anything else?
Am I crazy to think this is good?

[smittylube]

just tried it and no deal with these grips, outer radial bearing does not fit tight in the thrust location. Oh well.

[MotorRotor]

For our purposes, both systems have proven to work very well.

The main reason for putting the thrust bearing between to two radial bearings was to increase the distance between the two radial bearings. In effect this will increase the leverage the rotor head has in handling cyclic and collective loading.

Think of trying to lift a shovel of dirt while keeping both hands close together at the end of the handle compared to doing so with one at the end and the other further down the handle.

In our case these two distances are rather minor so not as advantageous as one may think.

[extrapilot]

Guys

Keep a couple things in mind. One is- many of these designers are just that- sort of industrial design or CAD/CAM/CNC people who can make things, but don’t understand the first thing about engineering. There are SO many examples of that in our niche- DFC is a glaring one, but just basic stuff like putting bolts in single shear, etc. So, point being- a lot of what ‘is’ is simply because others do it.

Another is, from an engineering perspective, all else being equal, it is really difficult to keep thrust bearings of our type free of contamination. These aren’t sealed bearings- they are way too thin for that. So, often, there is cause to put a thrust bearing inside a housing flanked by sealed radial bearing types. Yea, you can use seals etc, and that works for things like actuators (say, a ballscrew on a CNC machine). But in a heli head grip, you have very high centrifugal forces which tend to help in things falling out out unless they are very firmly held in position.

Anyway- there may be good cause for the particular install you are talking about. But high level, the above is probably useful for us generically.

[smittylube]

Originally Posted by MotorRotor

For our purposes, both systems have proven to work very well.

The main reason for putting the thrust bearing between to two radial bearings was to increase the distance between the two radial bearings. In effect this will increase the leverage the rotor head has in handling cyclic and collective loading.
.

I thought it might be a great idea except when the radial bearing was loose in the thrust location it won't work with this head.
I ended up drilling a hole so I could at least grease it without removing it.
Won't keep the grease out or in for that matter, but now it'll get greased more often