After a catastropic crash I rebuilt my Heli max mx400 pro. Now when I lift off I have sometimes limited control of yaw and sometimes even holding full right rudder the heli will still turn to the left. I have some idea's of what the problem could be, but am not sure, and want to see if anyone else has experienced this before. I did try increasing the RPM, but even with that the tail rotor did not become more effective.

Some of my idea's are

1. I replaced the blades with Align 325 carbons, and they look like they are longer than the originals. Perhaps spinning the larger blades torques the heli more and the tail rotor doesn't have the grip to keep up.

2. I replace whatever Futaba servo that was on the tail with a HS-55, perhaps this servo doesn't have the torque to effectively control the tail rotor on a 400 gram copter.

3. The guy at the hobby shop told me to toss my heli max tail and put on an Align tail assembly. I considered it, but for $100 I'm better off tossing the entire thing and buying the T-rex!

Thanks for any ideas!

well from my experience with that, idk what radio or what possible adjustments u can make with it, but with a computer radio try increasing the gyros HH rate to like upper 70's to lower 80's, also if that doesnt work try using subtrims, because mayb when u rebuild it u changed something that changed the servos nuetral point. thats how i fixed mine, good luck

what pitch does the tail go to, i.e. is your problem a set up problem, when your heli spins to the left is that the same way as the blades go! if it is it's probley the setup of the tail, you need to move your servo, or trim, I doubt it's the servo not have enough power,
and if it spinning the same way as the blades the tail rotor is over compensating so there more than enough power in the tail rotor and the servo,
I don't think it was not such a good idea to put 450 blades on a 400, there not built for a larger blade,

It spins opposite of the direction of the main rotor blade direction. I will try smaller blades, I just picked up some today.

lets know how it goes with the smaller blades, lets hope thats the problem