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Old 03-21-2011, 10:35 PM   #76 (permalink)
abek
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Join Date: Dec 2010
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>>Think about it. Why the gap of no metal in the blade grip holders? This is very unlike >>modern designs with other models like 450's and the like.

Makes sense to me. There should be transmission of lateral force all the way through to the centre of the rotorhead - then the stock bearings would not fail as they wouldn't sustain any lateral force.

I had a blade grip go flying after a blade strike - the feathering shaft had pull through the inner bearing, tearing it in pieces. My solution (in the absence of stock replacement bearings) was to use mainshaft bearings from a Walkera CB100. They have the same inner and out diameter as the stock item but are approx 30% thicker - this will at least provide more lateral strength that the current design has.

To accommodate the increased bearing thickness I used a longer screw (with locktite) to secure the bladegrip/feathering shaft assembly and I also had to shave off a couple of millimeters of blade-end by abrading the blade ends on some coarse sandpaper.

I made this change on both blade grips for weight symmetry and the setup is working well. I have avoided a blade strike of the severity that caused the problem so far but I keep checking for play in the feathering shaft and after another 10 packs or so its staying snug.
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