tail assembly twisted??

[johnnyf]

the tail assembly on my mx400pro twisted 180 degrees tonite!!! lucky i am only practising and had it inches from the ground!! i think it is due to the plastic tail support-the screws that tighten the tail piece have to tighten against this plastic piece-after a while this will wear out and get loose! i think the support should be made of aluminum or lite metal-anyone else have this problem? my chopper is only a few weeks old!! lucky i can't fly yet or that would have been some crash

[Raven_darkcloud]

Take a close look it might have ben the tail gearbox. Mine turned like that too and bent the tail shaft as well as removing the pin inside the gearbox that gose into the hole in the end of the boom. I put on alumi gear box after that. if the boom twisted then the front boom clamp in the frame is broken, there is a anti rotation pin the sticks out and lines up to a slot in the boom.

[johnnyf]

there is no pin in the gearbox of my mx??-also there is no anti rotation pin in the boom clamp?? the mx pro has the aluminum gearbox??
after closer examination i found that the tail gearbox bearing failed-i think that's why the gearbox twisted-one bearing is gone??
i wonder why there is no pin in the assembly to prevent the gearbox from twisting like that

[Raven_darkcloud]

the align alumi gearbox has no pin eather. You should replace the tail shaft too. A slightly bent shaft took out my tail case (plastic) after replaceing from first twist incodent. This happens on trexes too, but I dont know why. I whent with ceramic bearings and that seems better but dose cost some bucks. I also found that the align cf boom is slightly bigger around and holds in place tighter. This is a fairly cheap fix at $11. and looks much better than the gold alumi boom.
Mine is now more of a T-mix400 :mrgreen: but flys nice. Keep a good eye on the screw that hold the seesaw in place as they only go about 3mm into the seesaw and strip out easyily on the plastic seesaw. I had to replace my seesaw and not haveing 400 parts at lhs I did the trex head conversion. that was about $25 to do and makes the heli more responcive leaving me puting flybar wieghts on.
I am doing the build of another x400 this weekend and will be making a vido. If there is any point you whould like focused on let me know.

[johnnyf]

thanks raven- icalled heli-max-they are sending me a tail plate with bearing free!!
then after reading your reply i called them back and now they are sending me a new tail shaft also
i have never had such great service from anyone
heli max service is excellent!!!
i am going to email them a thank you note

[Raven_darkcloud]

Thats good to hear. The only way I noticed my bent shaft was that I had a wiggle in the pitchslider that the guy at my lhs noticed when I slowly turned the blades. I got yhe euro version x400 as plane kit so geting parts from helimax for free is no option for me.