trex tail help needed
03-09-2006, 09:57 PM
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trex tail help needed
i just built my trex and am having trouble with the tail not returning to center. if i move the rudder stick left it returns to center but if i move it right it doesent return back to center and i am constantly chasing the tail in flight. i am running a century rate gyro until my 401 arrives and a hs56hb servo. when i move the control rod by hand it feels free and i have checked for binding and all feels well and i have lubricated all moving parts. i can visually see it not returning to center so its not a gyro problem. im pulling out my hair on this one and dont want to shell out the bucks for a new metal tail just yet any help would be appreciated!
03-09-2006, 10:12 PM
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RE: trex tail help needed
If you're using a rate gyro, you need to have the true center absolutely perfect on your linkage setup. When it's hovering, you need to either make linkage adjustments until it stays perfectly centered or slide your servo on the boom. Prepare for a LOT of time & frustration to get a rate gyro working well. Now TRUE center and MECHANICAL center are two different things. Mechanical center is when the servo's centered and the blades have no pitch left or right on it. True center is when the servo is centered and the tail blades have the right amount of pitch on them to counter the rotation of the blades. I wouldn't mess with your rudder trims until you get it close, it'll just add to your frustration. If you want, once you get it close, you can probably trim it to get it perfect. I hope this helped and I didn't over explain it and insult your intelligence. Good luck!
An afterthough, the little link ends on the tail slider that actuate the tail grips tend to have a spring action that makes the tail not center well. The linkage will feel smooth, but the center will seem to bind a little. You have to loosen the screws on the rear (inside) of the slider to let the eyelets not only turn, but actually move in and out as the tail grips rotate. I had this problem with mine. Make sure you check this before trying to set your tail up or it won't center well.
An afterthough, the little link ends on the tail slider that actuate the tail grips tend to have a spring action that makes the tail not center well. The linkage will feel smooth, but the center will seem to bind a little. You have to loosen the screws on the rear (inside) of the slider to let the eyelets not only turn, but actually move in and out as the tail grips rotate. I had this problem with mine. Make sure you check this before trying to set your tail up or it won't center well.
03-09-2006, 10:52 PM
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RE: trex tail help needed
Agree fully with Troyswan. Get it approximately centered and when flying, trim it out as close as possible. If 'too far out', just readjust the 'neutral' position. By the way, don't worry about how it looks on the ground. Trim it out when in flight. Have fun with it, for with the 401 in HH mode it'll be "Boring"--After preliminary set up, the Heli just sits there like a statue!!!! I've been flying my Trex just 2 Wks, and into Heli's just 2 Mos, and can hover literally in one position for 10-15 Min without touching the rudder & Throttle, and just slight taps on the cyclic. Your current gyro will give you something to do(LOL).
Lloyd
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03-10-2006, 08:20 AM
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RE: trex tail help needed
i had the same problem. take you tail rotor off and the linkage and the slider so only the bar is left. take a piece of sand paper (very fine) and turn your main rotor so you tail spins and sand off a very small amount of metal unitll the slider slides smoothly. i had this very same problem and if you take off a little bit at a time then you will be fine. also make sure you have a good linkage to your rudder servo. the stock linkage sucks here is a link http://www.rcuniverse.com/forum/m_3995793/tm.htm
03-11-2006, 08:57 PM
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RE: trex tail help needed
If the link is smooth then it is a gyro problem and you must mechanicaly center the tail in nonheading hold to fly straight. If you do not do this then you will fight the chopper for ever. I had the same problem and the fix was the center in h mold was not the same in normal mode.
03-13-2006, 09:21 AM
#8
RE: trex tail help needed
If the 401 is in heading hold mode (light on steady) it won't return to center as you expect. On the ground its waiting for the helicopter to do what its told, if the heli nose doesn't turn it will hold the tail blades waiting for the heli to react, obviously it wont. In Rate mode (light off) it should center normally.
http://www.futaba-rc.com/team/team-tip-002.html
http://www.futaba-rc.com/team/team-tip-002.html
