How to zero out pitch/roll/yaw rates at center sticks for the bad mainboards

[Sowa]

I tried this out on my bird. I had to sub trim out the as3x system otherwise all 3 of my axis would drift. After sub trimming everything she felt a lot more solid in a hover, i'm excited to see how this translates into other areas of flight.

Good job on catching this DoubleCH

[tg43]

Wow! I just went through mine. Glad I found this thread as I don't visit this forum often. Thanks!

[DoubleCH]

You won't get cyclic/rudder drift when throttle is off (including throttle hold on) because gyro is off. Never heard any board needs that much subtrims but I don't know your 8FG subtrim step size compare to Spektrum TX. If that is indeed a lot of subtrim correction, you may want to consider warranty claim on the board or try a different TX first. Check swash leveling AFTER your subtrim correction and re-level if necessary. If you find the bird flipping slower to the left than right at full cyclic throws, or slower forward than backward at full cyclic throws, you may want to use trims instead of subtrims.

[craig303uk]

i've just noticed something strange, i set the sub trim in normal mode to stop the tilt, switch to idle up1 and it starts moving in the direction of the sub trim that i've just added, flick to normal it stops, flick to idle up2 its stopped.

i take off the sub trim, normal mode it tilts, idle up 1 it stops, idle up 2 tilts, i'm not quite sure why this is happening



think i might try a fresh model, wonder why it doesn't need sub trim in idle up1.

right so i've tried a fresh model, all flight modes need the same sub trim, i bind back to the old model and idle up 1 doesn't need sub trim just like it was before, hmmm interesting i'll need to take a closer look at the model settings for the flight modes to see what the differences are and try to find out why sub trim isn't needed.

if that makes sense its getting late here lol

i can't see why it would be doing that, i'll make a video shortly showing what i mean lol

video:

[ame]http://www.youtube.com/watch?v=WiCnfuiUnp8[/ame]


bed!

[Kalle75]

First of all :
Great guide for tweaking the driftprob. *thumbsup*
Thanks for that.

I just went through mine and YES. I had drift to right on roll and drift on tail servo.
Just gave 7-8 subtrim klicks left on roll and tail and all stood still.
BUT : When i unplug the battery and powerup the heli again, several times there is still a drift again. Not that much as before. But sliiiightly the swash moves sometimes. Tried powering up heli again....drift gone...next time...light drift again.
Did anyone experience that too ?
Greets Kalle

[DoubleCH]

From my experience, subtrim requirement may change a little bit with different supply voltage which is the only factor affecting subtrim requirement on a certain board. So my strategy is to subtrim with fresh battery because 99% of the time I spool up and take off with fresh charge and keep flying until end of charge. In case I need to spool up and take off near end of charge or in any discharge state, I just fly with the drift which is minimal. The cyclic/rudder drift towards end of charge is no worse than some mCPx v1 boards and is not enough to be a concern for me. Remember this is a workaround because AS3X on this bird doesn't allow user (or the software itself) to zero out pitch/roll/yaw rates. If the cyclic/rudder drift towards end of charge is of concern to you, consider calling HH to replace the board.

[Calmair]

THANKS DOUBLECH!!! I thought I just could not get a good board? Took care of all the problem.

[JayH]

I remember back years ago, this was a common problem with the old CSM gyros, the 360 suffered heavily from this. Always had to add subtrim, the CSM 540 was a bit better. always had to add subtrim. Dont know exactly what function of the gyro sensor the millisecond pulse is changing with a subtrim change. But good find none the less.. Im gonna go check mine real quick.. Ill report back.. Im about 30 flights on mine.. I dont hover long enough to see if it drifts, but it is slower rolling to the left than to the right. but in a inverted blade scrape it always seems to drift right on the ground. We will see what happens..

So, I just tried this. I have absolutely no drift on my board. all subtrims are at "0" I let it sit there for about 5 min. I pretty much mimicked your video step by step. Guess im lucky for now. next i will try to find out why the roll rate is less to the left.
BTW. my setup is basically stock with exceptions of the tail pitch slider, 2 holders for the tail rod and the metal tail blade holders..

[DoubleCH]

Consider yourself lucky with a 130X board that doesn't require subtrim. In that case, any minor drift in hover upright or inverted is not related to this issue. It's normal for inverted blade scrape to not hover perfectly level because the tail rotor shaft is not in the same plane of the main rotor disk. If you find max roll rates different between left and right, check servo center (not swash center) at center stick. If the 2 side servo tabs aren't at the same center/height, you'll get different max left/right roll rates.

[litehawkdown]

Originally Posted by Kalle75

First of all :
Great guide for tweaking the driftprob. *thumbsup*
Thanks for that.

I just went through mine and YES. I had drift to right on roll and drift on tail servo.
Just gave 7-8 subtrim klicks left on roll and tail and all stood still.
BUT : When i unplug the battery and powerup the heli again, several times there is still a drift again. Not that much as before. But sliiiightly the swash moves sometimes. Tried powering up heli again....drift gone...next time...light drift again.
Did anyone experience that too ?
Greets Kalle

When is the last time your TX was calibrated? Sometimes the pots do not return to center fully. You can check for that in your D/R and Expo menu or monitor screen . At center the values should read 0. -1, 1, 2, or anything more or less then 0 will send a stick input to the heli to move.

A fellow freaker pointed this out to me when I was having issues with My new DX7s and setting trims on my 250. Heres a vid.

[ame]http://www.youtube.com/watch?v=se2v_u5G7AI[/ame]

[tntburnett]

DoubleCH it works great I try ur subtrim . Great find .

Be blessed
Isaac

Sent from my A100 using Tapatalk 2

[litehawkdown]

Originally Posted by tntburnett

DoubleCH it works great I try ur subtrim . Great find .

Be blessed
Isaac

Sent from my A100 using Tapatalk 2

Were you hanging with NCcraig again? Bet his flying improved 10 fold since you saw him last. Piros, loops, flips, everything is better on the bird when you do this. If you are stick banging and it's not real bad on your board you won't really notice it's there. But it is there none the less and much better when it is gone.

Happy flying and god bless.

[Kalle75]

@ Hawkdown :

I just got a Spektrum dx6i few weeks ago which is a mode 1 transmitter.
Because i fly in mode 3 i just swapped roll and rudder cabel. Therefore i had calibration off centre and had to recalibrate.

But thanks for this hint. I will check once again.

Greets Kalle

[Smooth Chopperator]

Well I just got my 130x last week. It's my first CP chopper. It seemed to fly pretty good to me right out of the box but I read this thread and figured it couldn't hurt to run "the test" so I did so and my bird was exhibiting the issue of the swashplate moving with no cyclic input. Soon as I hit mid-stick the swash start tilting left and the tail rotors would pitch too, and they both would keep going and going until the servo throws were maxed out and then some. They would go so far that the bird would take like 5 seconds to respond to aileron or rudder because it had gone so far out of whack.

So I added some subtrim, ended up with aileron --> 10 and rudder <-- 8. The servos still travel at mid-stick with no cyclic but it's really slow now, to the point where you have to let it sit there for a couple minutes before it maxes out the servo throw. Seems to fly great except the rudder at <-- 8 it slowly yaws one way and at <-- 9 it slowly yaws the other... I need an 8.5 or something, but I can deal with that.

How much of a difference did it make in real-world flight I can't really say as I said I am a CP noob and it seemed ok out of the box for the first ~10 flights, although I did have an issue where on slow spool it always wanted to tilt onto its left skid. I could pop it up quick enough to where that wasn't an issue but it's not happening anymore since I've added the subtrim.

[Sowa]

try threading your tail rod in or out one to get rid of the drift.

[DoubleCH]

Adjusting til pushrod will not affect drift which is controlled by the AS3X. If you make the pushrod 1mm further back the AS3X will move the servo 1mm forward. Pushrod adjustment is to fine-tune max throw both ways (thus max pitch both ways, you want to equalize both).

[fabian1675]

Nice find! thanks for sharing, I did the sub trim method you've provided, now I'm just waiting for some parts to come in so I can try it out, so far everything looks good, swash no longer tilting and the tail now stays in the middle. .

[Steemo]

Mine was rolling left into the ground hard on take off, the only way for me to get it in the air was to spool it up at 0 pitch give right cyclic to level the swash while it spooled up, and the pop it up in the air quick. Once it was flying it was OK but the tail drifted clockwise and the cyclics felt mushy and unresponsive like it was fighting itself (which it was).

After following this guide my 130 fly beautifully with only the most minor of left roll on take off that is typical of small flybar helis. The one massive upshot is that my tail wags also disapeared too, maybe the whole system was fighting itself so much on aileron and yaw axis it kept over correcting

My mate who was already very happy with his 130x did it and couldn't believe the difference.

I recommend ANYONE to check theirs and apply this fix if they find the swash drifts at all with the motor unplugged and collective stick up.

[outspaced]

I finally got my head around this test and had to give 11R in aileron. I had already subtrimmed 8L in rudder just by hovering. Thanks for posting this, I'll be testing in a sec and I really hope it helps against the dreaded wag.
----
Well it certainly is more "hands off" in a hover, before it was always drifting fairly swiftly to the left and it almost felt odd not compensating for that!
As for the wag, hard to say because I have been trying a few other anti-wag measures today but the wag is pretty minimal right now. No kick in pitch pumps which is a good sign, I'm starting to get this bird flying nicely again thanks to HF

[PassinThru]

Well, so impressed with the helpful information in this thread and HF generally on this little bird! Aside from the lofty 'semantic' discussions of course.
I have done most of the mods recommended to get rid of my 130X tail wag. Still waggin'. However, when checking for servo creep I found that, while there was NO CREEP on any of the servos, the tail servo twitches. A related thread (I'm sorry I forgot which one) suggested that this indicates a faulty servo. I checked my JR9503 on monitor to see if it was telling the tail to twitch but the monitor window did not indicate any.
Do you think its the servo? the Gyro? I guess I could buy another servo to check that out but I'd like to see if any of you knowledgeable folks can nail this one.
Thanks.