Governor gain / tail wag

[Bking1340]

Good day all. Posted my problem about 2 months ago. Tried some fixes to no avail.
HW 100A platinum pro/650mx/HW rpm sensor/sk540 on Trex 550 - Gov gain of 35 worked great for about 10 flights, then my tail started to give a very fast small wag. Replaced every last bearing from TT to tail unit/tail bladegrips/thrust bearings - everything. Wag still remains - tail gain reduced to 30 - sloppy tail but still wagging fast.
Replaced main gear case with new 600efl with 112/11 slant gears - new bearing block bearings - Still wagging. Calibrated HW throttle range and sk540 again - no change.
Today I started reducing my gov gain from 35 with 2 click and ended up at 22. Now there`s 0 tail problems, but now it bogs/overspeed. I used straight throttle curves and then the HW governor and my tail are rock solid. So my problem are when I go above 22 sk540 gov gain - my tail wags seriously very fast and I need to be around 30-35 for headspeed to stay stable. I`m realy down in the dumps as I don`t know what else to try. Your help will be appreciated.

[thefrog]

What firmware on the SK unit and what logging mode you running?

[Bking1340]

Hi froggy - Sk540 3.15, never switched logging on since day 1. I installed the hobbywing rpm sensor after I upgraded to 3.15 and like I said, about 10 flights with 0 tail problems. Did not change anything on my tx or skookum program in this 10 flights. The tail just started wagging, that`s why I thought it may be a bearing, but replaced every single last one from tt to tail unit and main bearing block bearings. Now when I reduce my gov gain under 23, the tail are rock solid.

[thefrog]

You didn't upgrade the tail control linkages did you? I don't own any Align helis myself but I've been told by a few folks that on some models the latest tail control linkages bind.

If you switch on the vibration logging what vibes are you getting and where are they coming from? I had something like this on my Logo - it was a pita and I could never fix it.

[Bking1340]

Sk540 does not have vibe logging. Tail are as smooth as butter. It`s just akward that my tail are rock solid without the sk540 governor/with hobbywing governor/with straight throttle curves without any governor and with sk540 governor below 23% gain.

[georgi UK]

=] if it worked well for 10 or so flights chances are it's not the 540? rpm sensor, maybe?

[snaaakeey]

This unfortunatley is the last issue I have with the sk540. I run a hobbywing 120hv with a 4525le and the sk540 gov. My symptoms are precisly as you describe. With throttle curves or the built in gov the tail is totally still in a hover/flight. Sk540 gov engaged and the tail starts to figit. Not really a tail bounce. More a randon small wiggle. If i turn the gov right down to 22-24 the tail becomes still but the gov is no better than the built in hobby wing gov. Perhaps the hobbywing ESCs and the skookum gov has and issue. Im using hyperion and spektrum rpm sensors and Im running a bec so no issue with different grounds when using a rx lipo. Trying the hw sensor next and looking at rpm cable route and filter magnets but I think this is software based.

Has anyone else noticed this issue with scorp/kont/YGE ESCs?

I think its the gov kicking in and out all the time changing torque loads all the time. It needs a wider gov dead band so it doesnt hunt round on small RPM changes or it chould be noise related. Something to do with the back EMf from the motor or hw esc which the rpm sensors are finding hard to read causing the sk540 to get a bad data stream or its the gov algorithom being too keen at low gain settings but not being aggresive enough when the RPM really drops off.

Im at a loss my self so I'm interested to see if others have got any advice!

[thefrog]

Now that I think of it I had to turn the gain on my Logo way down to 22/23 too to get it to behave. This was with the HW100 Platinum and Hyperion RPM sensor. I thought it was the tail buzz in the Logo causing the issue.

[neoalchemist74]

I run the hobbywing 120 hv w/gov gain at 32 and have no problems. I've seen bad motor bearings cause similar problems. In any case you should turn logging on for a couple of flights then send a copy of the logged file to Skookum they may be able to diagnose it.

[Bking1340]

snaaakeey you maybe got something there. Will also order a new HW rpm sensor to take my sensor out of the guessing work (cheapest to start with). Will also do a logging flight and send it to skookum.
Must I do a 3d flight with logging on or just hover in normal/iu1/iu2?

[frypan]

I also have this.
I think its a chatter from high gain.
So lowering it should help. I was no.gov,when i
Switched.to using it it apeared.. Play with gov gains.

[snaaakeey]

Originally Posted by neoalchemist74

I run the hobbywing 120 hv w/gov gain at 32 and have no problems. I've seen bad motor bearings cause similar problems. In any case you should turn logging on for a couple of flights then send a copy of the logged file to Skookum they may be able to diagnose it.

How does the motor bearing effect the gov? I know it can effect the tail axis gyro with the high frequency vibes blinding the gyro but I think this manifests in a continuous tail bounce similar to high tail gain. My thing is defo a random unsettled wiggle. As you say I may be wrong about this so I'll check the motor bearings but I have checked this afternoon and both my 6hv and 7hv are doing the same thing. Both on the sk gov( both with new bearing) Both on hw (120/70a) ESCs . The 6hv in on the standard kit motor and the 7hv is running the 520 4525. So I reckon it's rpm sensor( don't think so though) sk540 issue or hw compatibility. Around 22 gov gain fixes both helis tail fidget but the gov let's the motor bog as badly as the hw built in gov ( which isn't terrible but still).

Just to clarify what I think proper tail behaviour is ( and what I get with throttle curves and internal gov) the tail in a hover is totally and utterly still. No lateral motion at all ( like the sim) even in light wind. Sk gov on and I get a constant random amplitude and frequency tail jiggle for 2-5mm ( ish)


Sent from The Pad of I

[heathy]

Any of you using a ferrite ring on sensors? I use the built in yge phase sensor and its solid, when i used hyperion sensors on the 6hv i remember symptoms as described.

Try some cheap ferrite rings

[ame]http://compare.ebay.co.uk/like/281040560013?var=lv&ltyp=AllFixedPriceItemTypes&va r=sbar&adtype=pla&crdt=0[/ame]

[frypan]

^ so much work lol

[Lighty]

I had the same issue with the Hawk 120 esc, spent SO much time ironing it out with no success.

There have been a decent amount of reports regarding the skookum gov not behaving. Some having success.

I switched back to the vbar and it just works.

So I guess there are combos that just don't work with the SK540.

Hope you solve it as I've been there before, it's frustrating.

[frypan]

Dang so theres no hope huh?

[neoalchemist74]

Originally Posted by snaaakeey

How does the motor bearing effect the gov? I know it can effect the tail axis gyro with the high frequency vibes blinding the gyro but I think this manifests in a continuous tail bounce similar to high tail gain. My thing is defo a random unsettled wiggle. As you say I may be wrong about this so I'll check the motor bearings but I have checked this afternoon and both my 6hv and 7hv are doing the same thing. Both on the sk gov( both with new bearing) Both on hw (120/70a) ESCs . The 6hv in on the standard kit motor and the 7hv is running the 520 4525. So I reckon it's rpm sensor( don't think so though) sk540 issue or hw compatibility. Around 22 gov gain fixes both helis tail fidget but the gov let's the motor bog as badly as the hw built in gov ( which isn't terrible but still).

Just to clarify what I think proper tail behaviour is ( and what I get with throttle curves and internal gov) the tail in a hover is totally and utterly still. No lateral motion at all ( like the sim) even in light wind. Sk gov on and I get a constant random amplitude and frequency tail jiggle for 2-5mm ( ish)


Sent from The Pad of I

The high freq vibes from a bad bearing are what I was refering to.
I will mention that my rpm sensor leads are isolated with heavy guage spiral wire wrapand my motor timing is slightly low at 7.

[neoalchemist74]

Originally Posted by snaaakeey

This unfortunatley is the last issue I have with the sk540. I run a hobbywing 120hv with a 4525le and the sk540 gov. My symptoms are precisly as you describe. With throttle curves or the built in gov the tail is totally still in a hover/flight. Sk540 gov engaged and the tail starts to figit. Not really a tail bounce. More a randon small wiggle. If i turn the gov right down to 22-24 the tail becomes still but the gov is no better than the built in hobby wing gov. Perhaps the hobbywing ESCs and the skookum gov has and issue. Im using hyperion and spektrum rpm sensors and Im running a bec so no issue with different grounds when using a rx lipo. Trying the hw sensor next and looking at rpm cable route and filter magnets but I think this is software based.

Has anyone else noticed this issue with scorp/kont/YGE ESCs?

I think its the gov kicking in and out all the time changing torque loads all the time. It needs a wider gov dead band so it doesnt hunt round on small RPM changes or it chould be noise related. Something to do with the back EMf from the motor or hw esc which the rpm sensors are finding hard to read causing the sk540 to get a bad data stream or its the gov algorithom being too keen at low gain settings but not being aggresive enough when the RPM really drops off.

Im at a loss my self so I'm interested to see if others have got any advice!

In re-reading your original post I see that you are using the hyperion sensor . Are you using acommon ground with that sensor? Because I believe it is nessicary. I am using the Hobbywing phase sensor which has two motor wire leads and does not need a common grd.

[Bking1340]

snaaakeey maybe we must flip a coin to see who`s going to buy a other brand esc. I just can`t see how I got 10 great flights with a 35 gain and then all of a sudden my tail started to shutter and below 23 the tail are solid again. Have ordered another hw rpm sensor.
In the meantime I`m going to use my hw internal gov which is not that bad, but the 10 flight on the sk540 gov was excellent - that`s why I want to sort it out.

EDIT:
Okay guys I have also reroute the rpm sensor outside the frame, away from any other wires. Installed a ferite ring from esc to sk540 and before/after rpm sensor - Still wagging.

[snaaakeey]

Originally Posted by heathy

Any of you using a ferrite ring on sensors? I use the built in yge phase sensor and its solid, when i used hyperion sensors on the 6hv i remember symptoms as described.

Try some cheap ferrite rings

http://compare.ebay.co.uk/like/28104...ype=pla&crdt=0

You always have the best toys Graham(YGE)LOL! You not usig the sk540 gov then?