130x Subtrims and gyro settings - your #'s

[DoubleCH]

Calibration procedure is in the firmware during power-up and I don't think it's end-user serviceable. The 130X bootup procedure is way faster than the mCPx and if I move the 130X around a bit during bootup it'll still pass calibration procedure and finishes bootup sequence not much longer if any. If I do that with the mCPx, it'll not finish bootup sequence until I set down the bird and let it stay still. This is evidence that the 130X has a much sloppier gyro calibration procedure and is most likely why many 130X mainboard gyros are off.

BTW, the key reason why using subtrims on the 130X and mCPx works is that both AS3X systems do not have self-centering alogrithm so the mainboard cares less what input values are center stick.

[HeliHoverAP]

Originally Posted by DoubleCH

You're way wrong and have brainwashed by what you've learnt from your general past experience on other helis. The reason the 130X swash drift is not to calibrate individual servo movements. It's because the gyros on the mainboard is off-calibrated (most likely a bad calibration scheme in the firmware). The mainboard mistakenly thinks that the bird has constant pitch and roll when there's no stick input (once again off-calibrated gyro).

So what does the mainboard do when it incorrectly reads the gyro? Tilts the swash in the opposite directions to compensate the constant pitch and roll rates that are off-calibrated just like you put constant stick input in those directions to compensate.

So what's the correct way to fix this problem short of replacing the board? Use subtrims to add constant pitch and roll rates that match what mainboard thinks are zero pitch and roll rates. That way, at no stick input the mainboard will read gyro values matching what the desired values are to not tilt swash to compensate.

First off, you need to show a little respect. Brain washed??? Wtf?

So tell everyone what your role was on designing the Heli along with the main board and gyros. The way your talking you obviously know more about the fbl unit than the engineers. Also just for kicks how long have actually been around Rc helis?

[NCcraig]

Oh gawd.

[DoubleCH]

Originally Posted by HeliHoverAP

First off, you need to show a little respect. Brain washed??? Wtf?

I apologize for that. Definitely shouldn't have used that wording. Sorry. I know subtrims are not the correct way to fix bad calibration in theory, but given the design and situation with the 130X mainboard, subtrims are the only way to fix the off-calibrated gyros without ill effects short of replacing the mainboard.

[jmisuraca]

So what your saying is that everyone who has added sub trim to stop the swash from moving, needs to call HH and request a new Main board because the calibration of the one we have is not correct?

[HeliHoverAP]

Thank you very much for the apology.

I am always trying to help, but when someone throws a stick in the wheel it kind of messes thing up. There is a lot of this on this forum and as you increase your knowledge you will start to see the same trend. I have several years experience in rc helis, have several years working in the industry and have been involved in rc in general since I was about 4 years old (getting ready to turn 35). I am by no means an expert or pro or claim to be. Working in the industry I can tell you that more than half the problems incountered were caused by or related to user error. I feel the same about some of the problems here, user error.

I received my 130x from a member here that could not get it to fly properly. I basically pulled it out of the box, did my setup, went outside and started ripping up the sky. You can see my 15th flight or so on page 16 (I think) in the vid section.

[HeliHoverAP]

Originally Posted by jmisuraca

So what your saying is that everyone who has added sub trim to stop the swash from moving, needs to call HH and request a new Main board because the calibration of the one we have is not correct?

Yes

There is a chance that your transmitter is off. I've seen this too.

[NCcraig]

Nah. I'll put a few clicks of subtrim in and call it macaroni. Right, wrong or indifferent.

[DoubleCH]

I really hope that Blade is going to work on the 130X mainboard firmware if not already for the next revision (I have board v1.3) to have a better gyro calibration procedure. Even the mCPx one works fine from day 1 and I never need subtrims on either of my mCPx boards and there's no report that anybody needs aileron/elevator subtrims for the mCPx boards. I really don't mind if it takes a couple more seconds bootup time if that means no subtrims required. I'm sure others will agree, too.

[DoubleCH]

Originally Posted by HeliHoverAP

Yes

There is a chance that your transmitter is off. I've seen this too.

Possible but base on the number of reports here about 130X tipping to one side on spoolup I doubt if there's more than 1% of those cases are because of off-calibrated Tx. Plus many of those tip over including mine happens only to the 130X not mCPxes or other helis using the same Tx.

[DoubleCH]

Originally Posted by HeliHoverAP

I am always trying to help, but when someone throws a stick in the wheel it kind of messes thing up. There is a lot of this on this forum and as you increase your knowledge you will start to see the same trend. I have several years experience in rc helis, have several years working in the industry and have been involved in rc in general since I was about 4 years old (getting ready to turn 35). I am by no means an expert or pro or claim to be. Working in the industry I can tell you that more than half the problems incountered were caused by or related to user error. I feel the same about some of the problems here, user error.

I received my 130x from a member here that could not get it to fly properly. I basically pulled it out of the box, did my setup, went outside and started ripping up the sky. You can see my 15th flight or so on page 16 (I think) in the vid section.

I know you're trying to help and I don't even doubt your past and vast experience on RC helis like many others here and I respect that. [Off-topic alert!] The thing is there are people who always follow the book all along and there are people who learn the basics but love to reverse engineer things. Guess which type am I. I don't claim to be expert either. I don't just blindly try things out and see which one works. I do things the way I do after I learn the basics, then study the particular situation, sometimes meaning reverse-engineering, and decide if I should follow the book and go my way. This doesn't apply to just RC heli. In my previous life of car racing, everybody says ITB (individual throttle bodies, 1 throttle per cylinder) is hard to setup, bad on gas, no low-end torque, idle rough, requires the most high-end engine management computer and is only good on the race track, all base on past experience of theirs and others. I've seen even National Champ caliber guru had to dump the project in the end. I proved them all wrong by fabricating most of the parts myself, fiddling and even modifying a low-end fuel-management computer, lots of tinkering time and effort, and made it not just works, but good on gas (even better than stock), even runs on hot cams (notoriously bad on low-end and drivability), smooth idle, super-flat torque curve, drives tame but at the same time you can really rip it up with insane throttle response, great high-end, passed emission tests with flying colors, and won National Champ races.

[coredump]

I agree with DoubleCH. If the TX is off, it should reflect to the mCPX as well.

I write my own FBL firmware on MCPX and maybe I will port it to 130x one day.
I think having a few clicks on the TX will not no harm at all. It will have exactly
the same effect as calibration properly, it will get rid of the accumulative error
on gyro measure.

It will have slightly impact on the swash, when the FBL control is off.
E.g. your swash is not exactly level due to the offset in the trim.
However, the in FBL system, the swash is not requier to be perfect
level to begin with. That is the advantage of the FBL system, the FBL
system use gyro feed back to correct the heli rotation. It will correct
the swash offset the same way as the wind blow on the heli cause it
to tilt.

I can't think of an actual real world harm done by setting subtrim
to correct the gyro offset, other than not feeling very good about it.
If you think of any real harm can be done by setting the subtrim,
please elaborate. I am willing to believe this is a firmware problem
not an user error, because we never see this kind of complain in
mcpx. Same user, same TX.

[DoubleCH]

Looking forward to your progress on the 130X firmware, coredump.

For some other FBL system that does self-centering algorithm and other complicated algorithm that requires reading center stick then subtrim will be an issue. With 130X's AS3X system, there's no self-centering algorithm and no other complicated algorithm that requires reading center stick (at least none that I can detect after some reverse engineering to see what exactly the AS3X does in any situation). The most important if not the only thing the AS3X care about stabilization is the roll and pitch rates.

If swash is not level when gyro is off, you can level the swash by adjusting servo linkages after you've subtrimmed the cyclic channels. Yes, I know it doesn't follow the basic rules of setting up heli but this is not a basic problem that basic rules are good enough to fix (except for replacing the board of course).

[Thursday]

I haven't added any sub-trim to my 130, but I'd like to start fine tuning it. All of you talking about being able to hands off hover, there must be something off with mine.

What's the proper way to set it all up mechanically?

[DoubleCH]

If yours flies fine without subtrim I wouldn't worry about it. The reason I need subtrim from day 1 is that without it the bird will want to tip off before even take off with no stick input, even if I try to take off as soon as gyro starts. If you want hand-free hover with a nimble heli like 130X, make sure you're able to consistently hover in one spot with very little stick movement 1st. At that point you'll clearly notice if you need subtrim and which direction. The best way to set subtrim for the 130X to overcome off-calibrated gyro is to unplug the motor an throttle up. If swash tilts and/or tail servo moves without stick input use subtrim to dial them out. Throttle down for 5sec to reset gyro and then try again. Only after that do you level swash mechanically with servo linkages when gyro is off.

[litehawkdown]

Originally Posted by HeliHoverAP

Well I was keeping my mouth shut because the op did not want any debates. Sorry.

If your are using subtrims/trim to remove drift in flight on a fbl Heli, there is a problem.

Let me explain. If you put, say, 15 clicks of up elevator, and the others are at zero, the elevator is going to travel 15 "clicks" further than the rest and 15 clicks shorter on the other side, and around 7.5 clicks around 50% deflection and so on. What you are doing is introducing cyclic interaction. You noobs that are using subtrim might not even notice it, but it is there.

This is a very basic Heli setup rule.

Who's being disrespectful here?

[NCcraig]

Originally Posted by litehawkdown

Who's being disrespectful here?

+1000.

The same guy who got all bent out of shape about a simple "brainwash" adjective that was apologized for. Granted you have been around here since 2009 and have a whole 300 posts so that counts for experience apparently. You may have been born in a hobby store, have a ton of "experience" and us little people need to wise up but there are alot of really smart people around here with a lot of experience regardless of the date they joined Helifreaks. Demeaning those who have opposing opinons does because of a join date on a forum does not make you superior. Speak about talking down to members. Just my two cents.

[DoubleCH]

I really do think he has good intention and I can certainly understand where he's coming from. Let's drop this and get back on topic.

[TomC]

Originally Posted by DoubleCH

The best way to set subtrim for the 130X to overcome off-calibrated gyro is to unplug the motor an throttle up. If swash tilts and/or tail servo moves without stick input use subtrim to dial them out. Throttle down for 5sec to reset gyro and then try again. Only after that do you level swash mechanically with servo linkages when gyro is off.

I agree, best way to start to set subtrims (if needed). You still may need to fine-tune them in the air though.

And, lets just try to stick with the topic; subtrims and gyro settings. Just want views of what guys are using, not a debate. Thanks guys.

Cheers,
TomC

[DoubleCH]

Originally Posted by TomC

I agree, best way to start to set subtrims (if needed). You still may need to fine-tune them in the air though.

I skip the in-air fine-tune part. Every heli has a tiny drift in the air. My goal is to prevent the bird from tipping over on spoolup. Unplug-motor-throttle-on-subtrim is good enough for the job for me and with just that I can already do hand-off hover for 3 seconds. That's good enough for me. I don't hover at one point for long with my normal flying anyways.