The help me understand how the gov works thread

[Luvmyhelis]

Alright guys, as per Omer's request. I started a specific thread aimed at guys like me that don't quite get the 'black art' of fully understanding how the Skookum gov operates in our heli's. At least I still struggle with the spool up hand off part myself. I get the raise the gain thing until we either hear the heli chirping or see some tail wag, that is after individually optimizing the tail gains.

I am going to be posting up half a dozen or more Sk files from my own and other helis that are struggling with getting the gov to simply hand over during spool up. Feel free to post your own logs up also if needed. Anything to do with your gov is welcome.
I have bounced through every spool up speed in my esc and played with the Skookum figures, as well as the start up power settings. Even stripping my mains with heli fast as some guys recommended. It has always been hit and miss.

Here is the first victim, My own 12s 600 Esp and here are the specs on it.

Scorp 4025-630 motor with mod 1 10T pinion. Kde mod 1 115t main gear.
Yep120hv esc with jeti 100a telemetry module and heat sink.
Herc bec running off a separate 3s 1300 lipo at 8.4v. Skookum 720B.
Turnigy TGY-725mg coreless cyclic servos with a TGY-805mg on the tail. RJX Fbl 600 blades on a CompassX head. I wont get into the other numerous mods as they aren't relevant. Although this is probably one of my favorite go to flyers and most certainly one of my most nimble helis.
The Yep values are:
Timing 12 pwm 8 Heli middle startup speed, Start up power at 8.
Dx16 Rpm 1 is setup at a flat 40 for these logs. Rpm 2 is at 60 and Rpm 3 is at 2300. I did have my Rpm 1 setup at a 1-40 curve earlier, but thought maybe individual stick timing might skew things? So I just set it up at a flat 40 out of Th for this log?

Skookum values are gov gain 40. Gear ratio at 46. Heli size 600.
Rpm 1: 1900. Rpm 2: 2150. Rpm 3: 2300. Low Ramp 80, High Ramp 130, Overdrive: 120.
Omer, is this all you need along with the playback log?

[omerco]

More than I need
The startup power on YGE/YEP should be the lowest. it kicks hard as it is. some use AUTO.

Please try 80 for LOW 120 for HIGH and 100 for the OVERDRIVE, with the same startup speed (middle).

If that doesn't work - try the heli fast. I'm sorry I'm just not home now to check my setting and I wasn't using this ESC for long time.

I will tell you you most certainly will NOT get a clean startup with this ESC - it has a built in kick to its soft start.

I will try and check your log later (the viewer is not on that comp.)

[Luvmyhelis]

Originally Posted by omerco

More than I need
The startup power on YGE/YEP should be the lowest. it kicks hard as it is. some use AUTO.

Please try 80 for LOW 120 for HIGH and 100 for the OVERDRIVE, with the same startup speed (middle).

If that doesn't work - try the heli fast. I'm sorry I'm just not home now to check my setting and I wasn't using this ESC for long time.

I will tell you you most certainly will NOT get a clean startup with this ESC - it has a built in kick to its soft start.

I will try and check your log later (the viewer is not on that comp.)

Omer, many thanks!

At least they don't kick as hard as my previous Hobbywings. Omg, those hit hard. I actually burned my 600 down on my coffee table while trying to utilize the bl heli mod on it trying to rectify that, then gave up.

Tried it on the lowest earlier, but will adhere to your specs.
It worked then with heavier Radix blades, but not the light ones I am running now.

[omerco]

1. definitely go to HELI FAST (or HIGH?): look at the graphs - see how the "governor output" goes all the way up to 100% because the SS is slower than the desired RPM raise for the setup (especially with the 130 HIGH ramp).



2. your gearing is not suitable to run 2300 governed. you need a bigger pinion:


3. from the time which your RPM takes to settle between RPM1/2 it looks like your gain might be too low?

[georgi UK]

=] Brilliant thread Randy! plenty of value for sure. You speak of the SK gov side of things which, by way of settings are fairly simple. It seems you would like to get into the nuts and bolts of it here, why not!

From the start, when Hyperion sensors were commonly used (analogue and dirty)ish signals) there were Only 2 types (Brands) of ESC's that could reliably handle SK external gov's, This applied to V-Bar also.

Given that 99% of all ESC's use either Atmel or SiLabs MCU's, then why should this be? perhaps make a note of that!

To me, it was clear at the start the key was about spool management, from the esc to the SK gov, It would be good if you can include an ESC start up procedure (as below) if we are going in-depth here, anything to do with Omer means boy We are!

The ESC has no way of knowing where the motor is when stopped, it doesn't know which phase to fire to get it rotating, and uses a stepper start for this. Now imagine your 40% FLAT SK gov commands in this mix??

Hence we need a ramp, and a handover sequence. so lets work from the ground up here to understand it fully, I know some guys will say yeah but I fire it up in idle 2 no issues, well that doesn't apply to everyone, your esc eagerly cooperates, and makes others think there is an issue.

I will come back to this Randy, so to finish off for now, we need 3 sets of data to establish the govs performance. this tells us many things, incorrect gearing, pitch range too high, lipo's seen better days and so on...

good example of ok, clean, plenty of headroom for the gov as the pack diminishes =

My log=



similar deal with an abort then re-spooled =

My log=



as you may imagine? that log means nothing to me??!

LMH LOG=



Best, georgi.

[Luvmyhelis]

Ok, just tried 2% (log 76) and Auto (log 78) at mid, Nada. But the heli did catch the gov in auto, but only with me giving it pitch, the second spool with it at zero it didn't catch.


Heli fast at auto, and 45% gain from the prev 40, thanks Omer! (log 81). I also dropped my bell gains down from 100 to 80 on this hop. Gov handed over! And it has more pop now.
11T pinion being installed (gear ratio 41.82), good catch, as I ran the 10T with larger blades and forgot to change it back to 10 for the shorter Rjx's. Omer, you rock!

Hey, brilliant post Georgi! And much of what I wanted to learn. Most the rest of the Skookum I have down, but no one has ever put together a comprehensive teaching for me that I have been able to really grasp overall for how the gov really works and what we want to see on the logs to solve this? Then it won't matter what esc we see, just how to read the logs to get them talking to each other properly for the hand offs.

And yeah, I am nursing some very old and punished packs through this summer. Kinda broke and waiting till this next spring to refresh them.

You bring up the Atmel and Silabs?

[Luvmyhelis]

Here is heli #2. Goblin early edition 700. Sk720B, Gryphon bec off 3s pack. Mks servos all around. Youngblood blades I picked up here from Tony.
Modified Mikado edition Scorp 4525-420 Ultimate. 20T pinion. Gear ratio 51. I prev flew with the KDE gen 3 motor w/ 22T at 2300HS but slowed it down this season.
Rpm 1 at 1850, Rpm 2 at 2000, Rpm 3 at 2150.
Low ramp at 80, High ramp at 120, and Overdrive at 130. Gov gain at 60. Heli size at 700.
Yep 120 with sink, since I toasted my Yge 160 in my Tri earlier I pulled the 160 out of this Gob and replaced it with this one. Last year I ran a Yge160/Kde gen 3 motor combo. It was pure wicked. But this year due to circumstances I decided to dial back and just work on my orientation training more than hard 3d stuff.

Yep values are,
Timing 12 Pwm 10. Startup speed, heli fast. Heli startup auto. ( I had it earlier at 8, tried various combo's)
I find it interesting here that with weak motors I can always get the gov to kick, or by running heavier blades? But on better motors I seem to have issues? Then again, I was used to slow spools? Now that may not be possible?

Same settings on the Jeti for this test. Just bang flat 40 out of TH for the spool. No hand off.

Also 21T pinion being installed for the next log, I had dropped back down to a 20 hoping to address the bog issue. It helped a little. Rainbows give this fits running the 21. If I can ever afford another decent larger esc I am def going back to the Kde. That was pure evil. As we talked earlier, I even dropped this Ultimate back into my 600 just to make sure I wasn't going nuts, if it bogged there I would know it was pretty weak in the knees. Kinda like my Align. Which was pure crap.

[Luvmyhelis]

Here is the last 600 log after the 11T pinion change. I need go pound this tomorrow to see how it all works.

Omer, You had me up the gov gain. So what exactly does the gov gain do? How does it actually work? And how specifically did you see I needed more gain? When I am looking at the ramps (throttle, gov, rpm) what are we trying to achieve?

[omerco]

Georgi your logs show the same problem as Randy's: ss too slow comparing to the low and high ramps: your gov output also goes up to 100% instead of just settling at the desired % for the needed rpm. As we want them synced you need to either increase the ss speed or decrease your ramps - mostly the HIGH.

[georgi UK]

EDIT
I just wish to clarify, the first two pics are my logs, the third one is from LMH,s log, is this what you refer to Omer, in which case I understand and you are indeed correct!

Thanks! georgi.

[Luvmyhelis]

Well, yeah, the log was labled lmh. Guys, I just am lost. I simply don't understand what low mid high, gov gains. And what the log figures truly mean? How does it all correlate into the proper hand off? Then work to actually govern head speeds under loads?

So far, even though my 600 now works. I don't have a real clue what the logs actually mean or what they are showing. Just the real basics for an old guy like me, class 101, from A to B for now?

Like what actual figures are parameters the Low actually covers? And why? Then what does the high ramp actually do? And look like in a proper log? Ect. Why do we really need 80 or 90% head room? Does the gov over rev under loads? Then how does gov gain effect this overall? When the hand off happens, why does the heli still slightly over rev before coming down into the designated Rpm? Or is that wrong and needing to be rectified?

This is the last log on the six after Omer's recommended changes. 11T pinion installed, gear ratio corrected. Start at throttle 40 flat Rpm1, then a hard pitch pump, then 60 Rpm 2 doing the same, followed by Rpm 3.

[omerco]

Originally Posted by georgi UK

EDIT
I just wish to clarify, the first two pics are my logs, the third one is from LMH,s log, is this what you refer to Omer, in which case I understand and you are indeed correct!

Thanks! georgi.

Georgi

I WAS referring to your logs, and to explain what I'm talking about and also to answer some of the extra Qs LMH asked now here is one of my logs:


and here is yours for comparison:


The differences between them are:
1. in my log the RPM goes to target and stays there. In yours it overshoots - hard to say by how much because in both of them you go to IDLE 1 before it settles.
2. In my log the GOV Output goes roughly to 50% and stays roughly there. In yours it goes all the way up to 100%, then when the RPM crosses target it starts dropping down (again hard to know what your hover RPM is because you go to IDLE1 - but I'm sure its not 100% ).

The reason for this is the ramps (usually its mostly the HIGH ramp) are to fast compared to the SS rate of accel. to have it correct they need to be in sync - meaning it should take the same time for the SS rpm and desired SK rpm to get to target.

When the ramps are too fast compared to the SS the RPM doesn't reach target when SK gov "thinks" it already should, so SK is adding too much throttle. then when the RPM crosses target the throttle is too high causing an overshoot.

What needs to be done - like the "fix" we did here with LMH - is to get the spool rates closer to one another: either increase the SS rate or decrease the ramps. The best IMHO is to choose your SS rate and then fix the ramp. I know 80 low 120 high works on all my setups for my spool rate (the log I posted is on a setup I never tuned it was like that from first Time with scorpion 160HV - using 80 low and 120 high).

[omerco]

Originally Posted by Luvmyhelis

Here is the last 600 log after the 11T pinion change. I need go pound this tomorrow to see how it all works.

Omer, You had me up the gov gain. So what exactly does the gov gain do? How does it actually work? And how specifically did you see I needed more gain? When I am looking at the ramps (throttle, gov, rpm) what are we trying to achieve?

Gov gain - roughly it is how fast the governor will close an RPM error, or you could also say "how hard" it will try and hold the RPM.

You can refer to it the same as tail gain - If it is too low the tail is musshy: doesn't hold well (same as RPM not holding). If it is too high: it will hunt - same as RPM hunting, or the "chirping " we hear or the tail oscillations we see due to RPM hunting.

I could say from your logs the gain is too low due to this:



1. when you change to IDLE2 the rpm overshoots and slowly goes down. with proper gain there would be less overshooting and faster correction after the overshoot.
2. when you change back to IDLE1 - again rpm goes down very slowly: you change to id1 at 79 sec and only at 94 sec it is settled. tooooooo slow.

If you have more Q about the ramps after previous post - do ask! I didn't look at all your logs and its VERY late here so please refer me to where you need.

[georgi UK]

=] Interesting Omer! What Is important here, is not all esc / heli combinations work in the same way! Although the SK gov is generic enough to cover many applications, but there will be variances between them, so we mustn't set a precedence that assumes we all fly the same heli's / hardware, this will cause confusion, and makes the thread useless to others...

You miss many points when looking at my log =

1, I reach full spool in a very short period of time.

2, the ramp up is near to vertical

3, the ramp up is clean, the whole system delivers what I want

4, the gov is locked in early and stays that way for the duration

5, going from a complete stop to a potential 400 mph tip speed in that time period would make you overshoot!

6, I'm really happy with it, no need to change anything

7, the purpose of the pic was to show Randy, stop mucking about with high low throttles, get a clean flight up then we can see where the problem is, as above, so below is needed here.

8, the high ramp has Nothing to do with a spool, this takes effect only at +50 throttle

9, I'm sure there are more but I need to eat......

------------------------------------

Randy, get a full flight log up and go from there....

[omerco]

Georgi

I didn't miss most of those points and i didn't say your gov isn't working - its working well!

I only say if you lower your ramp the spool will take the same time and you will avoid the overshoot. try it you can always go back!

To some - when the overshoot is big - there is a handover problem. I have dealt with many in the past years...and the main reason I wrote about your overshoot was because of LMH's question and specific problem - part of it due to that un-synced spool.

As for setups - I have 6 different Escs: Scorpion, castle, HW v3, older HW, Align and Yep. have to say:
1. starting with ramps of 80 low and 120 high (100Overdrive) always gave a good starting point. on my Scorp 160HV I didn't change a thing from day one - that is the graph I have posted above.
2. the basics I have written work the same for all of them I.E. - if you have an overshoot lower your ramp (high ramp), or increse your SS rate.

[georgi UK]

=] for whatever reason Omer? the overshoot seems to concern you more than me! I've flown the SK gov months before it was ever released, and have done ever since. In fact I debugged a rare serious issue on the throttle channel, Randy was one of the very few that watched a private video of that, he commented on the tail in landing? Probably the worst bug I'd had to deal with, it really scared me. Tail in Randy is better!

Given there is no RPM shown on my pic, the overshoot is nothing, my logs all contain some overshoot and settle nicely when the target has been met, we have to consider the drag is going UP by the square here, so there is no target that can be met if the gov has to ***** around within the same time frame, why is it important to you to try to eliminate what I consider to be a very good indication that my gov is perfect? It's not relevant or has any effect on flight performance? I don't get or share your interests in this?

[dcope17]

I'm going to chime in here...
I have a Goblin 500 with a YGE ESC and since day one, spoolup has been flawless.
Now, I also have a Furion 6 with a CC ESC and it had huge overshoots on spoolup. Finally got tired of it... so fix time.

LR 80
HR 80
OD 100

Since I didn't know what to change, I cut them all in half. 40-40-50. Spoolup was great... I then flew it to see if any of these number changes had anything to do with the GOV.
Nope, flew just the same with the exception of the better spoolup.
So I went back and lowered one at a time.
LR 40
HR 80
OD 100
Huge overspeed

LR 80
HR 40
OD 100
Huge overspeed

LR 80
HR 80
OD 50
Huge overspeed

So, I went back to
LR 40
HR 40
OD 50
All is good.

I do notice ( by sound ) that it spools up to say, 1700 RPM then a slight pause then it finishes getting up to the target 1800HS.
I'm guessing maybe 50-50-60 might bring it right up to speed... but the slight undershoot is a lot better than the huge overspeed.

Anyway, just thought I'd put that in there.

[Luvmyhelis]

All of this is much appreciated~ Omer, I did set up my gov % on the last posted log and it hits much more crisply... Georgi, So a mild overshoot isn't a big deal during spool ups. But, Omer we can address this? And thanks for the comprehensive help. Georgi, also the gov hands over in low or below 50% during the spool?

Dcope, this is great info and a good chime in. But what esc spool rate are you using to hit those? Thanks!

[dcope17]

I think I use "heli medium" on the CC... If there is a medium on the YGE... That's what I believe it's set at.
I don't remember what ramp and overdrive numbers I used on the YGE setup but the normal range numbers worked. Probably 80-80-100 or close to that. It just happened to work perfectly from day one.
I'll look up specifics of you want me to...

[Luvmyhelis]

Thanks, I have been pretty out of it the last few days. So I missed two weekend flying get together's over it so haven't been able to post up any full logs. dcope17, you got me thinking so I just pulled out my Gob 700 that has had the same hand over issues. And dropped the Skook low and high ramps after looking at the initial log I posted above. Seems the Ultimate motor rev's slower, far slower than the previous Kde. And I see the Skook gov ramp is higher and faster. So I drop my low and high ramps 10 each. Take the 700 out and bang, gov hands over flawlessly with no over spool.
And Omer, I did raise my gains 5 pts also. I never have had it high enough to chirp yet.

Here is the new Gob 700 log.