Originally Posted by 1Pilgrim
Yeah, my heli always points toward North when it has tbe.
Mike is the one who kept insisting that a cracked main shaft was a major source of tbe. I wasn't convinced until a couple of weeks ago when my heli became unflyable.
I stubbornly tried everything else but finally got around to examining the shaft more closely. Taking the screw driver that came with my heli I VERY gently pushed it into the top of the shaft. Sure enough, I found a hairline crack that appeared to have started at the topmost hole and propagated unward.
I replaced it with a new one and... VOILA! The tbe was worse than ever.
Huh?The brand new shaft was cracked!
Tried another new shaft - same story!
Finally in desperation I put a tiny drop of ca on the very top of the shaft where it would wick down into the crack. I immediately wiped off any excess glue and let the shaft cure for about 30 minutes before putting the heli back together... VOILA! PROBLEM SOLVED! I've been flying with the repaired shaft ever since with no hint of tbe.
At least one other peep has reported a cracked shaft right out of the package. I think it may happen when the holes are drilled too fast. It's worth checking out!
That makes perfect sense to me Pilgrim, as I mentioned earlier, I believe TBE is caused by any wear, damage, or mis-assembly, that causes the flybar to be "out of phase" with the head/rotor assembly.
But I think you need to let HH know about thier problem with a brand new shaft being cracked.