450 TREX 450 PRO DFC Tail drift

J

Joseph Orr

New Member
Hi there!, I am experiencing problems with the tail on my 450Pro, the tail will drift slowly to the right (fuselage left) during a hover and most prominently while sweeping the heli left or right, I have re-done the mechanical setup several times, the servo horn is near perfect 90, no sub trims, pitch slider is centred, displaying 47 left, 48 right in the 3GX Software, running 45% gain on the DX7s.

I have adjusted numerous settings within the 3GX software including increase/decreasing rudder locking gain from 70 to 100, collective pitch torque pre-compensation (collective pitch to rudder proactive compensation) from 50 to 100 and anti-torque compensation from the default value of 20 down to 0 and up as far as 60, without any success. I am currently running a pitch curve of 0*,3*,5*,7*,10*, 8* of cyclic, 35% expo on rud/ail/elev, flat throttle curve of 80%.

Tail servo is a DS520M

If anyone has any advice or a fix please let me know. Thank you in advance!
 
Tony

Tony

Staff member
Just a hint, if you hold ALT then hit 167 on the keypad and release ALT, it will put the "º" symbol after the number. Pet peeve of mine lmao.

Because you are running the 3GX, your gyro gain is going to be on channel "Aux2" and your Governor is on the Gear channel. Go into your Gyro menu and change the channel to Aux2 and the switch on "Gyro". At 45% rate, you should be getting some wag in there. Let me know if that works.

Also, change your pitch curve to 46, 48, 50, 75, 100 so that you have a little negative pitch when you land it and cut the throttle. Just in case you have some wind. Mid stick should always be 0º of pitch.
 
J

Joseph Orr

New Member
Haha, thanks for the tip, regarding the gyro gain, yes it is configured to the gyro switch on aux2 channel, gov is inhibited.
 
Tony

Tony

Staff member
Are you running the 3GX with Satellites only, or are you running a Spektrum Rx with the 3GX? Should have asked this first.
 
Tony

Tony

Staff member
Well I don't see anything that would cause a drift. You are on the Aux2 channel and say you have a LOT of gain and it's still drifting. Only thing I can think of is to upgrade to v3.1 (would do this anyway, it's MUCH better) and redo the DIR and Rudder setup. Fly it with the stock programming and see what the tail does. The tail on my 600 was solid on the stock settings. Had a WICKED wag in it at 65%, lowered down to 30 and it's solid. Never have to touch the rudder in a hover.
 
Tony

Tony

Staff member
Yup, And it's MUCH more stable than 3.0. You can download the update HERE

Make sure to uninstall the 3GX software from your computer, delete the file folder under Program files x86 labeled "3GX" then install the program. Then do the update from there. You must be running the 3.1 firmware on the computer to successfully install the firmware. That is what I understand anyway and it's the safest way.
 
Westy

Westy

LEGEND
º ... wow .... º it works!!!! I never knew that! .... Nice tip Tony! ºº

How far have you got your ball from the center of the servo arm (Where it pivots?)

should be 8 - 10mm.......
 
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Slobberdog

Slobberdog

Well-Known Member
Westy said:
º ... wow .... º it works!!!! I never knew that! .... Nice tip Tony! ºº

How far have you got your ball from the center of the servo arm (Where it pivots?)

should be 8 - 10mm.......
Click to expand...

ºLOLº, took me a while to figure out what you was on about Westy, but yey no more typing it...........mhaw ha ha ha
 
J

Joseph Orr

New Member
I have tried both inner and outer servo holes, just converted back to the inner hole, as I read that it allows for a higher gain amount and puts less stress on the servo.
 
Lee

Lee

Well-Known Member
On Mac its Option key and 0 ºººººººººººº :D
 
J

Joseph Orr

New Member
Ok, so the tail holds pretty good now since I flashed to v3.1, no more drift to the right, however! It will sometimes move out ever so slightly to the left or right during maneuvers, would this be due to slack in the control links?. I forgot to mention that the tail servo does buzz a fair bit, and sometimes emits a binding sound while moving, I think I may replace it soon…

I tried those pitch curves you mentioned Tony, worked out much better than having 0º at bottom stick position, thanks for that!

And the video
 
Last edited by a moderator:
J

Joseph Orr

New Member
Ok, so the tail holds pretty good now since I flashed to v3.1, no more drift to the right, however! It will move out ever so slightly to the left or right during maneuvers, would this be due to slack in the control links?, I forgot to mention that the tail servo does buzz a lot, and sometimes emits a binding sound while moving, I think I may replace it soon…

I tried those pitch curves you mentioned Tony, worked out much better than having 0º at bottom stick position, thanks for that!

And the video T-REX 450PRO DFC - YouTube
 
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