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Old Apr 20, 2012, 11:28 AM
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[QUOTE=i812;21386495]To date I haven't experienced problems with a bent Feathering Shaft, but I've read that a bent Feathering Shaft sometimes results in erratic/un-predictable flight handling symptoms.

I've read one way to inspect for a bent Feathering Shaft while it is installed on the heli is to remove one Main Blade, fold the other remaining Main Blade back so it is 90* away from its normal straight-out position, then verify the Main Blade does not flutter up and down as the Feathering Shaft is rotated using the Allen Key. If the Main Blade flutters while the Feathering Shaft is rotated, than it is an indication that the Feathering Shaft is bent.

Also, the Feathering Shaft can be checked for straightness after it is removed from the heli by verifying no air gap anywhere under its entire length as it is rolled on a flat surface.

I suppose if I see Main Blade tracking error, then among other things, a bent Feathering Shaft could cause it. So, if there is no Main Blade tracking error, then it is probably safe to assume the Feathering Shaft is straight enough, and doesn't need inspected?[/QUOTE]

NO
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Old Apr 20, 2012, 01:03 PM
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Why?

Not to argue, but wouldn't a bent Feathering Shaft reveal itself in flight as Main Blade tracking error?

I suspect that the tracking error would go from MIN to MAX as a bent Feathering Shaft rotates. Maybe at one moment in time a bent Feathering Shaft would be positioned for no Main Blade Tracking error, but at a later moment the bent Feathering Shaft may have rotated into a position causing Main Blade Tracking error.

Once again, to date I've yet to experience a bent Feathering Shaft, so it's all academic to me at the moment.
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Last edited by i812; Apr 20, 2012 at 02:31 PM. Reason: add last 2 paragraphs
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Old Apr 20, 2012, 01:08 PM
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I'll check but I seriously doubt my feathering shaft is bent. The o rings, however, might be worn out and I've read that will cause bad vibes. Along with main blades that are probably out of balance at near 6k rpm... Pretty sure that's the cause of my tail twitch, possibly the "phantom pitching" but probably has nothing to do with the tail blowing out. It'll 360 now when I give it full + pitch. I have a 4g3 7mm tail motor on the way.
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Old Apr 20, 2012, 01:41 PM
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The amount of vibe the Tail introduces can be inspected and eliminated by disconnecting the Tail Motor or removing the Tail Rotor.

If the Tail Rotor Blades aren't (equally) perpendicular to the Tail Motor's Shaft, and/or don't have the same pitch, then either of those out of balance issues will cause constant vibes. Because of the "inch-pound" effect, and the relatively long Tail Boom, a little vibe at the Tail Rotor may cause a larger vibe at the heli's body.

I suspect constant vibe(s) might not be the cause of the coming and going of intermittent "phantom" instability, but anything "cleaning" up the system towards a smoother flight is better than nothing.

To me, the most obvious cause of AIL and/or EL instability would be:

Servos (verify Servo Arms don't jitter at any Servo Arm positions while heli it held stationary)
Link Eyes (verify Link Eyes aren't to loose around their mating Balls)
Main Shaft (verify CF Main Shaft isn't bent?, or split especially at Rotor Head Screw hole(s))
[If the Main Shaft is split and/or it's Rotor Head Screw holes are worn out and elongated, then that may cause some phasing? and Blade Tracking problems?]
Feathering Shaft (bent causing problems as described in prior post)
Dampeners (worn and elongated as described in prior post)
Main Blade Screws (not too tight, not too loose, tightened just enough to remove air gap between Blade Grip opening and Blade Root as the outer tip of Main Blade is gently rocked up and down)
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Last edited by i812; Apr 20, 2012 at 02:44 PM. Reason: clarification
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Old Apr 20, 2012, 02:21 PM
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Quote:
Originally Posted by livonia bob View Post

If I remember correctly the question was about 4:20 and not 4/20 or 4-20...


Bob (and anyone else that wants to celebrate), have a Happy 4/20 Day. Not only at 4:20, but all day today.



Note to Bob: 4:20 is just an excuse to celebrate 4/20 everyday!
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Old Apr 20, 2012, 02:23 PM
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Originally Posted by itsmillertime View Post
I'll check but I seriously doubt my feathering shaft is bent. The o rings, however, might be worn out and I've read that will cause bad vibes. Along with main blades that are probably out of balance at near 6k rpm... Pretty sure that's the cause of my tail twitch, possibly the "phantom pitching" but probably has nothing to do with the tail blowing out. It'll 360 now when I give it full + pitch. I have a 4g3 7mm tail motor on the way.
Hey itsmillertime,

is your heli off balance?
It could be messing with your gyro so Im just wondering if that may have anything to do with your forward pitch.
Good luck, hope you find the cause.
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Old Apr 20, 2012, 05:15 PM
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Quote:
Originally Posted by i812 View Post
Why?

Not to argue, but wouldn't a bent Feathering Shaft reveal itself in flight as Main Blade tracking error?

I suspect that the tracking error would go from MIN to MAX as a bent Feathering Shaft rotates. Maybe at one moment in time a bent Feathering Shaft would be positioned for no Main Blade Tracking error, but at a later moment the bent Feathering Shaft may have rotated into a position causing Main Blade Tracking error.

Once again, to date I've yet to experience a bent Feathering Shaft, so it's all academic to me at the moment.
You can have a bent feathering shaft that only causes a lag on one blade. This throws off the balance of the heli's blade system while not necessarily causing a tracking error. The feathering shaft actually doesn't rotate the blade grips are rotating on the feathering shaft...
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Old Apr 20, 2012, 05:18 PM
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Quote:
Originally Posted by i812 View Post


Bob (and anyone else that wants to celebrate), have a Happy 4/20 Day. Not only at 4:20, but all day today.



Note to Bob: 4:20 is just an excuse to celebrate 4/20 everyday!
Next year how about sending me something to celebrate it with?? I'll even do a 4:30 day this year if you hurry..
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Old Apr 20, 2012, 05:46 PM
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Originally Posted by livonia bob View Post
You can have a bent feathering shaft that only causes a lag on one blade. This throws off the balance of the heli's blade system while not necessarily causing a tracking error. The feathering shaft actually doesn't rotate the blade grips are rotating on the feathering shaft...
Thanks, I hadn't thought about Blade phasing.
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Old Apr 20, 2012, 06:43 PM
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Originally Posted by livonia bob View Post
Next year how about sending me something ...
PM sent
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Old Apr 20, 2012, 07:27 PM
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Quote:
Originally Posted by livonia bob View Post
You can have a bent feathering shaft that only causes a lag on one blade. This throws off the balance of the heli's blade system while not necessarily causing a tracking error. The feathering shaft actually doesn't rotate the blade grips are rotating on the feathering shaft...
Quote:
Originally Posted by i812 View Post
Thanks, I hadn't thought about Blade phasing.
Outside of removing a Main Blade and manually rotating the Feathering Shaft, or completely removing the Feathering Shaft, is there an easier way or any other clues that would indicate a bent Feathering Shaft? In other words, is there a way to spot for a bent Feathering Shaft on the "fly" without having to do any disassembly?
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Old Apr 20, 2012, 07:37 PM
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Bob @ helircstore.com sent me some goodies and it's time for a rebuild. I'm not going to let the mini beat me, lol.


Edit* Whoops, wrong pic.



But on a side note that was a mean little guy, striked my foot numerous times. I'd be pissed off too though if someone parked on me but I had to hold him down so he wouldn't get my dog. I'm a little rusty at herpetology and couldn't tell if it was a moccasin or just a harmless water snake.
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Old Apr 20, 2012, 07:45 PM
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Quote:
Originally Posted by i812 View Post
Outside of removing a Main Blade and manually rotating the Feathering Shaft, or completely removing the Feathering Shaft, is there an easier way or any other clues that would indicate a bent Feathering Shaft? In other words, is there a way to spot for a bent Feathering Shaft on the "fly" without having to do any disassembly?

Strange vibration that you can't find the cause of.. Doing the remove a blade and rotate the feathering shaft is so quick and easy to do it's the first thing to check.. But sometimes I have done the check and it seemed OK but problem didn't go away till I replaced it. And the dampers. My D02S has been needing a new one for months now.. But as it's still flying I'm waiting to bend it a little more first..
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Old Apr 20, 2012, 07:49 PM
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Oh, and does anyone have some of the 003 orings they can send me? I don't really want to buy 50 of them.
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Old Apr 20, 2012, 08:18 PM
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itsmillertime, did you receive your 350mah 25C lipo order from aliexpress? how is it?
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