I have an E-Flite MCX which has recently started to drift in little (2') circles when I try to hover. The nose is always facing the same direction, but high, low, wherever I go it looks like it is revolving around an unseen point. Since I'm just beginning with helicopters, I have broken and replaced upper blades, lower blades, the fly bar, head and even the landing gear(!) but the flight problem seems to have crept in somewhere along the way and I don't know where to begin.

Another thing I noticed with my MCX that has started to happen recently is that as the battery gets low (last 20 or 30 seconds of flight), the heli starts to pirouette loosely to the left, tail following the nose in a spiral. I just land and turn everything off, but I'm wondering if one of the motors might be wearing out. If so, I guess I should replace them both, right?

Any ideas about what I can do to correct these issues?

I have a CX2, not an mCX but it sounds like you're describing TBE (Toilet Bowl Effect). Primary cause is usually a bent inner or outer shaft which may be the case if you've been crashing around a lot. The other possibility is your blades are tracking correctly possibly because they aren't balanced.

The asymetric spool down behavior may be related to a bent shaft, but I wouldn't jump to conclusions about a failing motor at the end of battery charge. I'd run down the other issue first then see what happens to performance. You may want to time your flights to avoid running the battery down so far. You really shouldn't run it down more than 50% charge, but since these batteries are so small and cheap, I'd time how long your typical flight is and cut back by say 1/2 minute and quit there.

Hope this helps until the calvary arrives who fly mCX's!

Mack

Thanks for the reply, Mack. [sm=thumbs_up.gif] I'll take your advice and replace the blades, followed by the shafts until I find the solution. Thanks again!

Jason

Hi Alpha,

I have an mCX as well and my "toilet bowl effect" was solved with replacing the inner shaft and balancing new blades.
To balance my blades I screw them together as if they are on the heli and take 2 dixie cups or glasses and put them together and set the blade assembly on the edges of the glasses or cup by the ball links and adjust everything till the blades pivot very freely. Then once everything is set and they pivot nicely the heavier blade will drop and tell you that you need to add weight to the opposite blade. I use very small pieces of scotch tape on the underside of the blades to balance them. Just add or remove tape untill the blade assembly is somewhat balenced on the cups or glasses. That will eliminate alot of your problems.
As far as the left yaw when the battery starts dying, you can counteract that with right trim and just keep adding trim till the heli stops yawing to the left. If you have all the trim set and the heli still yaws to the left then the battery is tired and you need to stop flying and put in a new charged battery.

Enjoy!!

Thanks tomcat same technique as with the CX2. Sometimes you can balance the blades by swapping out different blades until you get a good match, but the scotch tape works very well and is almost faster.

If you remove the inner shaft and roll it along a flat surface with the head off the edge you can confirm if it's bent or not.

A good crash will bend that sucker every time.

Mack

Nice trouble-shooting techniques! I have no doubt that I will be able to correct the problem with both of your advice. [8D]

Thanks Again,
Jason

have you messed with the plugs in the mixer board? If so don't unless your trying to fly inverted I have a couple times but when I want to I just look at my t-rex 450 but if your just starting don't look at that until the distant future once you feel confident in this ask me and I will tell you how to invert it so you can get used to a little acrobatic flying then after that I would move on to the Blade Cp2 or go straight to the blade 400 if you have the money.