Hi all you Trex boffins out there - a question to help a frustrated Trex'ian.

I have a Trex 450XL CDE - Love it - it was flying so smooth - was flying it one day, setting up Idle Up for the first time, when I lost Radio Control for some reason - the Motor Shut down completely (luckily) and she nosed into the ground from about 15 feet up - the only thing broken that I could see was one of the Main Blade Grips - which I then replaced - but now - I cannot get the blades tracked at all - turning the links on the longer rods - from swash to mixer arms - makes it go either too little - i.e. blade flies lower, or too much - higher. I had set up my pitch curve to 50 inh 50 inh 100 - to basically get 0 pitch at 50% throttle stick - i.e. if my throttle stick is at 50% and I switch to idle up - they both match pitch wise - as idle up goes - -10deg to 10 deg with 0 at 50%throttle stick - so now I have the blades tracking fine until the head gets up a bit of speed - i.e. about 50% - then the one blade starts to go higher.

I have also now changed to a new Main Shaft and New Spindle shaft - no difference - still does not track!!!!

This Trex tracked so well before!

Any ideas what might be wrong - what could still be causing this blade tracking differrence - could the Main Rotor Housing be bent - i have examined it and it looks OK - as before - always had a bit of a wobble at low rpm then straightens out when head speed gets up - ALWAYS been like this - and most EP helis I have seen seem to be similar with a plastic Rotor Housing!!

I am also going to replace the main bearings that support the shaft in the frame - they have a little play in them!!

HELP - I need HELP - this is really bugging me - i don't want to carry on buying all new parts and finding none of them fix the problem!!!!

Thanks

Sandy

I take it that you have new blades on ?
Are the blades balanced length and chordwise? Any blade twist will change tracking with changing headspeed.
Is your swash ok, tight with no play?
Your main rotor housing could be bent, but really it would effect tracking through the whole RPM band. I would check every ball link on the swash, every head component for play, basically from the servo's to the rotorhead.
That's my best guess

hi bloogyct

did you check your feathering shaft ,(parts number hh2007)

to check that ,put your hex key to the bolt an turn ,if it s bind you will see it

bonne chance

stéphane

I had an issue like that not too long ago. Turned out that one of my ball link screws was backing out. I didn't notice it until it was in hover, when the tracking went south. Futher investigation uncovered a loose screw that looked tight...

Hi guys - thanks for the replies - will do as you say and check the whole head assembly for 'loose' parts - I did notice some play in the 2 bearings holding the main shaft in the frame - slight side to side and back to front - so have replaced those with aftermarket bearings - seem to be a lot tighter now!

Thanks again

Sandy