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redjoe's blog
Posted by redjoe | Mar 14, 2011 @ 04:20 PM | 9,056 Views
I believe I see what is probably the matter with the blade grips and their bearings, and this problem with the mCPX.

After flying a couple times just fine, I was interested in the possible bearing issue affecting my new heli, so I dismantled my ends tonight.

First, I found that the bearings were installed as follows. (out is facing blade and order is assembled order)

Blade grip 1 - Gold bushing(with feathering shaft screw inserted, Philips head)
Blade grip 1 - Outer bearing(gold out)
Blade grip 1 - Inner bearing(gold in)
Main rotor hub side 1
Main rotor hub side 2
Blade grip 2 - Gold bushing
Blade grip 2 - Inner bearing(gold out)
Blade grip 2 - Outer bearing(gold in, with feathering shaft inserted, Flat head)

So, already a problem in my eyes. Pulled the bearings out and inspected them.

Horizon Hobby has a diagram of the blade grips here.
http://www.horizonhobby.com/ProdInfo...0_Bulletin.pdf

You notice on their diagram, it shows the gold bushing should be installed between the main rotor hub(rubber bushings) and the blade grips on both sides with the small flange from the gold bushing toward the bearing race. Mine had the gold bushings installed incorrectly. (look at my assembly order from factory)

Now, look at the bearings. (tapered race bearings)
You will see, the gold side is the cage holding side, and this is obvious because the race of these bearings are tapered. On the gold side, the thickness of the race is much less than the other...Continue Reading