Rudder pitch travel problems TREX450 CF2

chance4snow04 · Hover Master Joined: 01 Apr 2009 Posts: 13

in a recent crash, I cracked the plastic rudder housing and replaced with lexact part. the control arm and tail rotor control assembly are the same...

all settings in the Tx/gyro/servo are same and were working perfectly before.

Now I when light on the skids I have no positive control over the rudder. Iff I barely move the rudder stick I get response but with full rudder either direction I get no response.

Removed main blades and spooled up to half throttle, what appears to be happening is too much travel on the rudder control assembly (its bogging the motor when the rudder control assembly reaches full travel left and right.

how can it be over traveling now if nothing was changed on the servo, servo linkage contol arm, or tx settings are all the same?

tombo242 · Posted: Tue May 12, 2009 7:03 pm Post subject:

Hi Chance4snow04,

My first guess, and only a guess without seeing for myself, would be that the crash has effected the gyro. If you take it out of the rudder control and link the servo direct do you then have normal travel?

Good for the brain these helis, rarely had problems with fixed wing. Wink

chance4snow04 · Hover Master Joined: 01 Apr 2009 Posts: 13

took it to the local hobby shop and the guy found the problem in the tail drive gear assembly...

the nylon gear that the belt rides on was slipping on the shaft! But it only sliped when you put full pitch on the rudder... This was hard to see when the heli was spinning becase the rudder never fully stopped ; i.e. the gear was spinning just not as fast as the shaft that was turning it.

we found the problem by holding the main shaft stationary and then spinning the tail rudder by hand.... then we saw belt actually spin the gear on the shaft.

bought a $30 cnc upgrade for the tail drive assembly; actually the only TREX upgrade they had.... problem solved!~
I will say its a pain to change the rudder drive assembly if you are not trying to dissasemble the entire main frame!

thanks for the input

tombo242 · Posted: Fri May 15, 2009 12:16 am Post subject:

Thanks for letting us know what the problem was chance4snow04. You must be one of the lucky ones having a LHS on hand, seems a rarity on this forum.