SK540, 720...step by step 'how-to' governor setup for nitro

[RontaryUS]

I got a couple inquiries through PM so I thought I would share the step by step explanation in a post on how to properly setup your governor with the SK for nitro powered helis. Apologize if it has been posted before.

Step by step:
- keep gov off in software for now
- setup a linear 0-100 throttle curve in radio, setup hold at 0% and idle up 2 at 100% straight in radio
- calibrate your radio sticks in wizard (keep servo travel to 100% in radio), throttle should then display 0 to 100 in software and match stick travel
- setup your carb with throttle servo arm and carb arm at 90 degrees to throttle link when at mid stick on radio (50 throttle value displayed in software), ensuring the carb is open to the 50% mark on the carb.
- adjust in radio the throttle servo travel to reach 0 and 100 marks on the carb without binding when at low throttle and full throttle stick respectively. Both the low and high end servo travel values in radio should be close if mechanical setup is correct (within 10% difference)
- in software, go to idle up 2 and hit 'set high throttle'
- go in throttle hold, hit 'set idle throttle'
- activate governor, check 'nitro' and 'manage collective',
- enter proper gear ratio
- use 80,80 and 100 for low ramp, high ramp and overdrive and 50 for the gain as a starting point
- setup normal, idle 1 and 2 curves in radio as per wizard
- verify setting by switching between modes, corresponding HS will be highlighted in green in software
- adjust the throttle cut value in radio to ensure the carb is fully closing when hitting throttle cut
- fire up engine and play with throttle trim on radio to have a good idle
- check in your radio monitor what % throttle it corresponds to and set this value as a flat curve for throttle hold
- connect to software, switch to hold and hit 'set idle throttle'
- you're all set!

There are other ways to set the idle (adjusting bottom of normal throttle curve to idle point...) but I found the one above the safest, giving you idle in throttle hold, throttle cut and allowing the SK to see a 0 throttle value at idle for proper spoolup.

Let me know if any question!

[itbvolks]

Rotary -

Thanks again did putting this together. Huge huge help

[omerco]

Very nicely write! i don't have a nitro and i understood all

Sticky?!?!?!?!?

[itbvolks]

Definitely should be a sticky since there is so little Nitro specific setup information from Skook.


Nicely done.

[georgi UK]

=] hey! nice write up to avoid frustrations! sensors are another area that need adding to this content, plus the disable gov on tail bank 2 for tuning purposes, if you want to expand it more?

[RontaryUS]

Thanks. I may expand to these aspects later, this is a good idea.

[mat081278]

What about the Autorotation Bailout for Nitro.
If I understand correctly, module must show a TH value from TX under -10%,
so in Nitro configuration the motor will probably cut if you have your 0 point for THold.

If you set your IDLE point to 20% of servo travel, and so get your THold at -15% and your TCut at -20%, I think it is quite dangerous because in this case your FailSave is set at 20% of Servo Travel.

An other question, is there a soft start spool up in Nitro.
I mean if you start whith THold (IDLE UP2) and you release the THold, is there a slow servo motion ?

[RontaryUS]

If you set it up as I explain above you will have an auto rotation bailout (TH will put the engine at idle as well as a failsafe if setup correctly) and a soft start on spoolup for take off. It doesn't work the same as when gov is set to 'electric' so the setup method for nitro is different.

I would not advise spooling up from idle up with a nitro and the SK gov needs to see a ramp up in the throttle value to engage.

[mat081278]

Seem to be clear, thank a lot.
Should not be safer to have a TCut function in case of failsafe ?

[RontaryUS]

That's a good point. With the current software revision, the throttle channel sends a 0 value when in failsafe i.e idle your engine as you mentioned. You cannot customize this. To me it is fine as it leaves your engine running and you would be able to rev it up again if the radio signal is back on. I agree that in case things go wrong you could get a chicken dance on the ground but a throttle spring may prevent it in some of these situations.

I guess it comes down to personal preference, like setting 0 pitch or few degrees of negative pitch for failsafe...The second can be a good bet if it fails upright but not if inverted. My choice is 0 pitch as I fly at least as much inverted as upright.

[mat081278]

To be honest, I think also that 0 pitch is the best option in case of failsafe.
But for Throttle the best one is TCut. THold is not so dangerous if you set up it correctly.

Let's see if dev can add this feature in a next software version.
Thanks for your support.

[RontaryUS]

Mat, I thought through this again. If you set your failsafe after step 7 and before the second to last step of the tutorial I wrote above, it will failsafe with closed carb i.e engine shut down

[mat081278]

Did not succeed to get TCut for fail safe. But doesn't matter.
Did my Firsts flights today with my Rave N. Gov works perfectly (add to increase the gain to 80%).
Very simple to configure, and works perfectly with my monster OS 105.
Thanks.

[gitbse]

So this setup enables the governor, without the need for a backplate sensor? Or do I need to get the sensor to make the gov work? I'm very familiar with SK, however this will be my first big bird nitro.

[mat081278]

You really need a sensor. A back plate one or other, but SK need to know the motor speed.

[Colin Broughton]

Thanks RontaryUS, this was extremely useful. I just finished building and setting up my first nitro and these instructions were so easy to follow and the heli fired up without issue

[USA_1_INK]

Hey Guys
I know the Gov on the Sk540 works great on my Nitro Scale Md500 .
But What about Gov. issues with a Gasser ?

What I have is a Whiplash Gasser with a VX300TT .
The problem I am having is the pickup sensor . I have the sensor mounted for picking up off the Main Gear . I have the gear ratio set to 1.00 in the SK software . But in the SK view screen , the sensor shows the triggering of the magnet pass for one complete rotation . Then off , for one complete rotation . Instead of a short blink as it passes for each rotation of the magnet .
I haven't had much luck with the Stator Gator , or the GV-1 sensor mounted to pick up the signal off the motor fan .
Just need some ideas on what to look for ? Been flying this SK540 on 3 other Heli's with great results on the stability .

Thanks Karl

[Luvmyhelis]

Anyone?

[6.6leater]

Just thinking out loud here about the gasser engine rpm sensor. I looked on the website, it didn't say if 2 or 4 stroke? If 4 cut the desired rpm in half in the sk software? May be worth a try. Another thought would be to make an inductive pickup around the plug wire to the sk. The only thing to figure out would be what the correct voltage going to the sk, making it think it is like a gv1 sensor.

[DCflyer]

Ran across this old video tonight and thought i'd post it here in case someone has the same issue. This is not me, but I was curious if anyone knew what might cause with this person is experiencing with his governor operation on his nitro. Might help someone in the future.

VIDEO0062.3gp (1 min 41 sec)