I'm not talking about slight shifting as the voltage drops. Rather it seems like the trim will radically shift from one flight to the next. Sometimes full left trim, sometimes neutral. I'll stop and fiddle w/ the propo and gain, it will work for a bit, then change again.

Weird thing is sometimes gyro gain seems locked in, then the tail will develop that bizzare twiching thing.

This is starting to get me PO'd.

running dual tail motors, plasticblades, and 1300mA Lipo.

stock head.

anyone else notice this trimming issue?

I obviously have to adjust the trim as the battery drains, which is one reason why I am going to a belt system in the future. But I have also noticed that diffrent batteries require diffrent trim settings on the tail. Unfortantly I don't have much of a suggestion for you on this if your using the stock transmiter. What I do is I have several profiles on my transmiter for my cpp and I pick the profile that fits the battery. That way I don't have to retrim to each battery it is already pretty much set.

One other thing to note is how much tail power you need will vary based on your pitch too. So what may work at a hover about a foot of the ground (say 60 to 70% throttle/pitch)...will not work for a higher pitch or throttle setting. This extra pitch creates more drag and thus has a greater torque effect. So as you increase pitch you will need more right side trim.

If your tail is twitching back and fourth then my guess is your gyro gain is set too high. Basicly your gyro is over-correcting and this is what is causing this twitch. If it not going back and foruth (also described as the tail wagging) then something else may be the problem. But keep in mind these POS stock gyro's are not very good at holding the tail as it is....that is why I plan to get a heading hold gyro soon (maybe 2 weeks when I have more funds).

Just checkin to see if youre disconnecting the battery every time you adjust the prop'l?

Also check to see that the tail is spinning the right way. Im sure youve got it right but Im just chuckin ideas.

I think maybe I was setting it up wrong. I found a video over @ runryder that clearly show the setup. The basic idea there, is set the gain to the lowest setting, then adjust the propo. I'm guessing I had the propo wrong, and was using too much gain to compensate.
I'll give this a try later and report back, but for now I gotta get some work done. (in order pay for more toys)

BTW: the guy @ the new LHS I found (who's a pretty advanced heli pilot) told me I could avoid most glitching by unwinding the receiver antenna. He said the 'coiled around the strut' thing is a BAD idea. Got it running down a long plastic tube now.

Also put a ferrite ring on the main motor lead, just for added peace of mind.

Ok, after following the setup video, things are better, but this is still one touchy little beast. Now I can get the thing to hover and hold the tail pretty steady without any input. However if I land and take off again, I might have to make slight adjustments to the rudder on the TX.