Alright, I did a search and found nothing on this issue.
I'm running an Align 35A ESC with a 430L 3550Kv motor on a T-Rex. The ESC is brand new and jsut replaced from a Phoenix 35A. Almost every time I put a fresh lipo in it (2000ma 16C) it seems to have a different headspeed. While I was setting it up with a tach, I had to adjust the end points on my throttle curve to even get it to initialize (low EP had to be lower than -100%) and once I had it tached at 2200RPM in governor mode, the throttle was at 36% to make it hold 2200RPM (yes, I too thought this to be strange). A day later, I took it outside for some test runs and the head speed then was WAAAAYYYY low. Had to increase the throttle to 76% to get it back to 2200RPM. NEXT BATTERY I had to bring it down to 50% to do the same thing. The next few times it sounded varied, but not by enough to re-tach it.
Tonight I had it up again and most of the times it sounded right and sometimes seemed a bit fast, by more than 200RPM off (I've flown this heli for a while, I can get pretty close by sound) Mid-point through a battery, I had made a landing, hit the throttle hold for a minute to talk to someone, then spun it back up and the headspeed had dropped by 100 rpm or more than it was at before landing it for about 20 seconds.

Anyone have any ideas? I've set up a few Align speed controllers, but this is the first one I have owned. The settings are as follows: brake disabled; mid-timing; middle battery cut-off; Helicotper 2 governor mode; and medium speed correction.

Thanks

The only thing I can think to try is to turn off the govener mode and see if it holds without it. If not, then I would start looking at pitch links and see if you have something moving, or a ball link that got pushed off the ball and is floating on the back side of it. Thats where I would start.

The throttle curve must be linear when programming the ESC. You can change it to something else after ESC programming.
Also try changing helicopter 2 to helicopter 1.

Nix governor mode, its next to useless on Align ESC's from what I've seen and tried.

Yes, this I am aware of. I have also used both governor mode and standard throttle curves on ESC's. I have always had good luck with throttle curves, like 'cuda states.....but I do love the "usually" hassle-free setup of governor mode.

I take it noone's ran across this before with an Align ESC, so I guess I'll assume it's defective.

Thanks.

Ya need to listen to BarracudaHockey!!!

I run no governor mode and a straight line throttle curve of 100 100 100 100 100 100 100. You don't need a governor for the T-rex. Got this info from Nick Maxwell who is an Align demo pilot for the 450 and 600.