V-Bar governor vs Scorpion governor head speed

I have been using the V-Bar governor driving a Tribunus ESC 06-120 on my Logo 550 with 14 tooth pinion and 1100Kv motor.

With the V-Bar governor it easily achieves the 2000 head speed that I want to run at

Doing simple maths with no regard for efficiency suggests with a pack voltage of 24V I could get to 2400 so plenty of head room I think. I set a fictitiously high head speed and could actually achieve 2350.

In governor setup with Scorpion App enabled I select Scorpion governor.

So I switch to using the Tribunus governor and use the ESC setup wizard with "Other ESC" to do a throttle calibration after disabling the Scorpion app.

Now the highest head speed the model will get to is 2030 suggesting the throttle calibration or the throttle / ESC out value is not a true 100% but something less.

Is this correct?

Is there a difference in the throttle / ESC output percentage when using Scorpion governor?

If I disable the Scorpion App and run through the setup for "Other ESC" I do get the 2350 highest achievable head speed head speed. In governor setup I select external governor.



Edited 2 time(s). Last edit at 05/14/2019 04:39PM by Andy from Sandy.

Consider - giving a RPM in VGov which effects 100% Throttle bar can't be kept under load. i suggest 70% of the bar at 0deg running on the ground as useful ;-)

Scorpion obviously calculates a "useful" value as RPM preset in their own mode.
But - to be sure - if you go into the Gov Setup and increase the full throttle value - does this have any effect?

regards (EN) / Gruss (DE)

Rainer Vetter

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I increased the value from 100 to 120 maximum for high value. It made no change to head speed.

I have to conclude though with the ESC programmed for gov with reclac values in the scorpion app it somehow limits the maximum achievable head speed.

If in the scorpion app I select external governor then once again I can get the highest head speed. It appears the Scorpion governor is limiting the head speed somehow.

Hi Andy,

afaik most ESCs do that, to preserve some headroom for governing the head speed.
And since this should be possible from battery full to empty, with the voltage drop taken into account, this headroom can imo easily be something between 10 and 20 %.

In external governor mode, or any other direct mode without brake, they act like a throttle servo and leave the throttle management or governing to a different authority.

Kind regards

Eddi

Born to fly ...
forced to work.

Quote:

afaik most ESCs do that, to preserve some headroom for governing the head speed.

Hi Eddi, Which others?

In the past using Kontronik governor I would be instructed to not set a throttle / ESC value greater than 85% to leave headroom. On spool up the achievable head speed is noted. This is the figure then used throughout the flight. However the ESC would allow me to set a higher ESC value with the consequence of possibly not maintaining the head speed toward the end of the flight.

Using the scorpion governor it is imposing its own unknown headroom so the actual maximum achievable head speed is unknown. I now have to set ESC value to 100% to get desired head speed. So this is not intuitive IMHO.

There is a RPM correction parameter which you call RPM adaptation but the percentage of what? I can see how increasing it give an increase in head speed but I don't understand its implication.



Edited 1 time(s). Last edit at 05/15/2019 03:16PM by Andy from Sandy.

Hi Andy,

I have not tested for a long time, but I think Kontronik ESCs also left some headroom, the highest head speed achievable in Mode 4 was lower that what you got in Mode 1 for example, if memory serves.

I would even go further, only set 65 % (at fully charged batteries) for the Kontronik Governor, to allow headroom for the full duration of one battery.
This way, the ESC will be at 85 % or more throttle opening, to the very end of a battery cycle, and still have headroom.

But we are guessing here, I'd be curious what Scorpion tells about the governor mode of their's ...

Kind regards

Eddi

Born to fly ...
forced to work.

Scorpion Tribunus governor can be used with 100% throttle value and still have headroom to govern perfectly. It sees the throttle percentage only as a rpm request so you can run 100% throttle values. This was confirmed by both Tony and Georges.

VControl, VBar on all.
TDR, TDR2, TDF, TDS and TDSF
Peter

I now have that information.

What isn't so clear though is the amount of headroom.

This is not so intuitive as it was when we could decide on the ESC throttle value based on our flying style, expected voltage dip and final pack voltage at the end of the flight.

As an example I have been able to use the v-bar governor quite happily with a 14 tooth pinion. I cannot get to the head speed with the scorpion governor and will have to get a 15 tooth pinion and try again.