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View Full Version : CX2 Outer Shaft Problem - Noise and reduced flight times


BryMeister
09-19-2007, 02:29 PM
Hello there. I have been flying my CX2 (http://www.helifreak.com/buynow/keywordclick.cfm?bid_id=4264) since July '07 and love this bird! I have done some extensive modifications to this Heli and for a while she was flying perfectly. Now, I am having a problem and I thought I would consult the collective mind to get some ideas before I tear it down later tonight.

I flew 4 packs last night in my garage. I noticed an unusual sound coming from the Heli as she flew. It sounded a little like the sound of a playing card being placed to hit the spokes of your bicycle when you were a kid. During flight, I noticed that the power seemed to die off more rapidly, as compared to previous, post-mod flights.

So, I took the Heli up to my desk and began checking it out. The inner shaft rotates fine. The outer shaft, on the other hand is "catching" on something that I cannot see as it rotates. You can't get it to happen in any one place around the circumference of the lower shaft rotation consitrently, but I definitely noticed that the outer shaft will feel like it is catching on something. When it does, you can easily force it to the point where it will move past the catch and continue smoothly. You can also hear it. It sould like a plastic "click". I have already checked the gear teeth and they are fine.

So, anyone care to jump in here with suggestions? I am going to tear down the Heli tonight and inspect the outer shaft and bearings. Just from looking at the Heli, I cannot see anything wrong, but you can defintely feel and hear the problem.

Note that the bird still flies and handles well. It's just that I can definitely feel a loss of power earlier in the battery pack (http://www.helifreak.com/buynow/keywordclick.cfm?bid_id=5287) than before, as if there is binding on the shaft.

P.S. I know that my outer shaft is slightly bent. This is no big deal, as it is not severe and I have a replacement. However, I believe that the lower rotor / outer shaft issue is separate.

Kindling Maker
09-20-2007, 06:04 AM
Check out the main gear, when you bent the shaft it my have ground some teeth off of it. I have done this MANY times. Helihobby has a kit to extend the distance between the rotors, it is a good kit plus the gears that come with the kit are more durable.

BryMeister
09-20-2007, 09:07 AM
Thanks. You were right on. I found some damaged teeth after I pulled the outer shaft. I could not see the damage until I looked at the teeth against a white background. I replaced the outer shaft and gear and now all is wonderful!

I have the X180 motors on my Heli and with this problem corrected, she flies VERY nice! The only sound you can hear is the sound of the blades moving through the air. Sweet!