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

[DoubleCH]

I've enjoyed flying my subtrimmed bad mainboard for the last 850+ flights in the last 3 months and many more to come. This thread is for those who is willing to give it a try but not sure where to start. As I've always said, call HH to replace your bad mainboard if possible (hint: no guarantee the replacement will be any better). Or just subtrim it once and forget about it ever after.

[ame]http://www.youtube.com/watch?v=3z7W7CbLGnM[/ame]

[lannny]

I simply clicked the swash to the left for about 14 clicks and now perfect. I did'nt go in to subtrim like you did, but I'll try that. Have you upgraded, or did anything during 800 plus flights to keep her airworthy?

[DoubleCH]

Some of my documented mods:

https://www.helifreak.com/showthread...62#post4344262

The most important works to keep the bird airworthy is to spin-balance tail rotor (add tape and trial-and-error), make sure A gear spins true on mainshaft so that it won't touch elevator servo, additional bearings behind stock flange bearings, and subtrim my bad mainboard. There are many smaller things I've done early on but I might have forgotten and/or they aren't as stuck out as those I mentioned. At 400 flights, I was still running the original tail pitch slider. And at 850+ flights now, I'm still running my original flange bearings.

I assume you mean flight trims using the trim switches next to the cyclic stick. They work just like subtrims except that they change only center stick values not full-throw stick values while subtrims shift the entire stick range. Which of trim/subtrim works better depends on what causes the mainboard pitch/roll rates to be off. However since max cyclic stick throw determines initial swash tilt and sustained pitch/roll rates but not max swash tilt which is preprogrammed by AS3X, it's quite likely you won't be able to tell the difference. If you do, just choose whichever way that gives you as close max stick throw performance both ways, which BTW is also determined by how level you set the swash after trimming/subtrimming and how close to center the servos are at zero collective pitch.

[litehawkdown]

Nice vid DoubleCH

Hope it brings understanding to this issue. All HH had to do when I called was to tell me that subtrim has no ill effect on the AS3X gyro and I would of be a happy camper.

My original 3in1 needed a lot of elevator,aileron and tail subtrim to fly right. It would quickly lurch forward and left on spool up. It made it impossible to get it off the ground without heavy cyclic stick movements while still on the skids.

My second 3in1 goes to the right only. It was less noticeable but still annoying.

Seriously guys. This is worth a look to see if your 3in1 has this issue. The only reason I caught it was my 130 was instantly rolling into the ground on spool up. I bet there are more units like my second 3in1 out there that are not as bad that cause slight drifting. The kind of drift one would find normal in a Flybared heli. If you can't fly your 130x hands off for 5-10 seconds or your piros are wobbly and veer off. I bet you have this issue and don't even know it.

I wish HH would speak up or chime in on this issue. I think they know about it. They just know how bad it is. If they had to replace all the faulty boards it would be a nightmare for them. If they tell you to use subtrim they go back on every AS3X manual written where it states "0 subtrim".

[mtuccio]

Very good info DoubleCH.

Thank you for taking the time to put this video together....

[litehawkdown]

Edit. Ya I was drinking and posting

[Idle Jack]

my 130 only has this swash effect when the motor is engaged and it will reset after a few seconds of the motor stopping is this normal or a similar problem?

[edjo69]

Idle Jack, That is the problem.

DoublCH and others. I have 2 130's and both of them have this issue. I thought I had fixed it but during many pms to DCH I realized I got caught up in my excitement for having found the cure only to realize; no-go. My two 3in1's only have the aileron servo slowly fall until they bottom out, all other servos are unaffected (both 130's) at least my two birds are consistent!! Any way, one requires aileron subtrim 6L and the other 8L and after this leveling procedure they have stayed level for about 3 flights each so far. Thank you DCH for "pushing" me that my fix was a placebo, if you hadn't I would have lived in an ever drifting lala land.

[litehawkdown]

Originally Posted by Idle Jack

my 130 only has this swash effect when the motor is engaged and it will reset after a few seconds of the motor stopping is this normal or a similar problem?

That's it. Test like this

Unplug your motor from the 3in1.

Turn on Transmitter.

Plug in your flight battery.

Use only up collective with the TX.

Watch the swash and how it behaves.

If it starts to tilt at all you have the issue.

You can counter the tilt with the proper amount of subtrim.

Every unit that has this issue seems to behave differently. Some have 1 axis effected some have all 3.

The issue only shows up when the AS3X is operating. So it will not show up in Throttle hold or with out the motor signal working.

It is a real nice hands off hover when the FBL system is working right. Loops piros everything is better. The bird is solid. I literally flip the bird inverted and can just let it sit there in the sky hands off.

[DoubleCH]

Originally Posted by Idle Jack

my 130 only has this swash effect when the motor is engaged and it will reset after a few seconds of the motor stopping is this normal or a similar problem?

It's "normal" for this mainboard problem. The problem itself is common but not "normal".

The reason it resets after motor has stopped for a few seconds is that gyro turns off at that time and in gyro off mode, servo works directly to cyclic stick input. That's why we've been emphasizing to unplug the motor and throttle up to turn on the gyro to see the effect.

[NCcraig]

I just went through a subtrimmed out my 130 per this method. My swash would tilt right, thus the drift right on take off and my tail servo was moving the tail blades causing my yaw drift in flight. Adjusting the aileron and rudder subtrims kept the servos from moving and should take care of my litle problems in flight.

Thanks DoubleCH!

[litehawkdown]

Originally Posted by NCcraig

I just went through a subtrimmed out my 130 per this method. My swash would tilt right, thus the drift right on take off and my tail servo was moving the tail blades causing my yaw drift in flight. Adjusting the aileron and rudder subtrims kept the servos from moving and should take care of my litle problems in flight.

Thanks DoubleCH!

I bet it improves your flying. I felt like I found a cheat code to a video game first time I flew a locked in 130x.

[NCcraig]

This should go to the sticky section of this forum! I usually don't chime in and make suggestions, but this thread is very beneficial.

Sent from my DROID RAZR using Tapatalk 2

[edjo69]

Originally Posted by NCcraig

This should go to the sticky section of this forum! I usually don't chime in and make suggestions, but this thread is very beneficial.

Sent from my DROID RAZR using Tapatalk 2

Especially since probably a vast majority of these boards have the issue and it just gone unnoticed or attributed to adjusting to a new helo.

[litehawkdown]

+1 on the sticky. Cleaning up this issue makes your 130x SOLID. I know I beat this one to death but I do it for a reason.

[syzygyQ]

This is a good guide that should be stickied. Some of the boards have very solid and stable imperfections that can be made right with the DoubleCH adjustment protocol.

The prospect of heli boards requiring trim to get right is industry SOP. It opens no can of worms to just put it out there that some of the boards may need to bet tweaked to be right, and here's how you do it.

[ZOEZHELI]

Thanks Double CH. Just went through the process on both 130s. the swashes stayed level fortunately, however if I leave the pitch gimbal at mid stick or higher, over a 5-10 second period the tail blades very gradualy "creep" to full pitch,by moving the rudder gimbal in the opposite direction,the tail slider in fact does go all the way in the opposite direction and drives in both directions equally. The swashes remain level during this process, when I hit throttle hold (taking the gyro offline or lower the stick and wait 4 seconds),swashes lower -still level and tail blades return to straight, 90 degrees. Leave the pitch gimbal at midstick flip throttle hold off and over 5-10 seconds tail blades again "creep" to full pitch. Tried using rudder subtrim in both directions to center tail blades at mid stick,they remained at full pitch. Have not adjusted gyro gains,DX6i monitor shows all sticks centered with pitch gimball at mid stick. Zero subtrims,travel adjusts at 100%.Is this the gyro causing this? Normal? Fix? Would not have seen this had I not been checking per your thread. Thanks again

[litehawkdown]

Originally Posted by ZOEZHELI

Thanks Double CH. Just went through the process on both 130s. the swashes stayed level fortunately, however if I leave the pitch gimbal at mid stick or higher, over a 5-10 second period the tail blades very gradualy "creep" to full pitch,by moving the rudder gimbal in the opposite direction,the tail slider in fact does go all the way in the opposite direction and drives in both directions equally. The swashes remain level during this process, when I hit throttle hold (taking the gyro offline or lower the stick and wait 4 seconds),swashes lower -still level and tail blades return to straight, 90 degrees. Leave the pitch gimbal at midstick flip throttle hold off and over 5-10 seconds tail blades again "creep" to full pitch. Tried using rudder subtrim in both directions to center tail blades at mid stick,they remained at full pitch. Have not adjusted gyro gains,DX6i monitor shows all sticks centered with pitch gimball at mid stick. Zero subtrims,travel adjusts at 100%.Is this the gyro causing this? Normal? Fix? Would not have seen this had I not been checking per your thread. Thanks again

I had this on my first 3in1. Tail servo always creeped over to full extent on the bench test. No amount of trim seemed to stop it dead. In the end I just trimmed my tail while flying. Seemed to be the only way to get the tail drift to go away.

[DoubleCH]

Originally Posted by ZOEZHELI

Thanks Double CH. Just went through the process on both 130s. the swashes stayed level fortunately, however if I leave the pitch gimbal at mid stick or higher, over a 5-10 second period the tail blades very gradualy "creep" to full pitch,by moving the rudder gimbal in the opposite direction,the tail slider in fact does go all the way in the opposite direction and drives in both directions equally. The swashes remain level during this process, when I hit throttle hold (taking the gyro offline or lower the stick and wait 4 seconds),swashes lower -still level and tail blades return to straight, 90 degrees. Leave the pitch gimbal at midstick flip throttle hold off and over 5-10 seconds tail blades again "creep" to full pitch. Tried using rudder subtrim in both directions to center tail blades at mid stick,they remained at full pitch. Have not adjusted gyro gains,DX6i monitor shows all sticks centered with pitch gimball at mid stick. Zero subtrims,travel adjusts at 100%.Is this the gyro causing this? Normal? Fix? Would not have seen this had I not been checking per your thread. Thanks again

Sounds like you misunderstand the goal of subtrimming the swash and/or rudder. You don't drive the swash and/or tail pitch to center with subtrim. The goal is to prevent swash and/or tail pitch drifting away from center. You need to get ready at the corresponding subtrim highlighted (i.e. any roller button movement is going to change subtrim right away). Use cyclic and/or rudder stick not subtrims to center swash/tail-pitch. Let go to center stick and watch which way swash/tail-pitch move and use subtrim to counteract the drift. Re-center swash/tail-pitch with stick as often as necessary and retry.

It's trickier with rudder because on top of yaw rate, AS3X needs to go after position (heading) as well. When tail pitch drifts off to max, it may take some time with rudder stick in the opposite direction to get desired heading to move back to current heading and the tail servo to start moving again. By the time it moves it'll move very fast and when you return to center stick, desired heading may have already passed current heading and you end up at the opposite direction. The key is never let tail servo drift to any extreme end. Use rudder stick as often as possible to keep tail pitch centered and use subtrim to prevent it from drifting, even if that means you need to use one hand on rudder stick and another on roller button.

[ZOEZHELI]

Thanks Double CH. I appreciate your reply ( and litehawkdown's) . The mechanical side of these helis are easy for me.I had a discussion with my plank flying friend this past weekend about how I need to learn as much as possible about the subtleties of programable radios and their interface with the onboard electronics.My MCPX V2 in April and my 2 130Xs July 2nd are my first experience with Gyros and HH electronics. I understood the goal, I knew that I missed something that's why I posted the question. I do now understand the process. I'll follow up first thing tommorrow. I've always been impressed with the breadth of knowledge available on Heli Freak I'm always learning, no matter how good you become,in reality ,your still .. learning. Thanks again for your help, it is greatly appreciated! 11:00 A.M. 10-18-12 Update both helis are now rock solid ! Thanks again for sharing and patience !