Sk720 Governor Question

[wearman]

I need help understanding why my head speed is too high (2285)!

First the details:
Trex 700, 112T main, 12T pinion, Hobbywing sensor, Scorpion 4035-560 kV motor & Commander V opto 50V ESC. Calculation yields gear ratio input value (in software) around 45 (don't have it in front of me).

I turned the ESC governor off and set my 3 RPM's to 1700, 1800 and 1900, with corresponding curves in my JR x9503 radio (ramp to 40%, straight line at 60% and straight line at 100%. As I have read the Gov wizard is pretty straight forward, and except for setting my throttle idle position I did everything it said. My throttle endpoints are 100%H and 100%L and watching the monitor the throttle channel moves up to 40% in N and 60% in ST1 and 100% in ST2. I use the throttle hold switch for safety.

When I spool up in normal mode the speed climbs to an ungodly 2285 using a my tach (the tach is correct), even before I tached it I could tell it was too fast as it was screaming like a banshee.

It lifted off and hovered normal, but that speed is too fast so I landed and shut down. I rechecked it in the software and it still read the same rpm settings. I am at a loss, any ideas out there?

Thanks in advance

[dogbreath]

Double check the gear ratio in the SK setup. That gave me fits until I got it right. I thought I had a sensor where I just put in the gear ratio, but then it turns out I had to multiply by the 10 poles and divide by 2. I still had to do my elementary school math correctly, which took two tries! I believe the solder in Hobbywing sensor just uses your gear ratio because it's placed between two poles--no need for motor poles & all. Dan

[wearman]

Originally Posted by dogbreath

Double check the gear ratio in the SK setup. That gave me fits until I got it right. I thought I had a sensor where I just put in the gear ratio, but then it turns out I had to multiply by the 10 poles and divide by 2. I still had to do my elementary school math correctly, which took two tries! I believe the solder in Hobbywing sensor just uses your gear ratio because it's placed between two poles--no need for motor poles & all. Dan

Thank you for the input, but I do not think the number is the issue. If I divide the main gear (112) by the pinion (12) x 10 poles / 2 I get 46.67, which is what I have entered. Everything I have read on HF states the hobbywing sensor requires use of this formula. Am I missing something?
??

[georgi UK]

=] please post a log for this issue....

[wearman]

Originally Posted by georgi UK

=] please post a log for this issue....

Thank you Georgi, but have only recently looked at the logs. I purchased the Skookum logger pro for $35. The only files that are present are vibration files and when I open them they show a low vibration of 1.2 on the scale. I went into the SK software and changed the logging to playback mode. It is raining so it may take a day or two to spool it up again, though I would rather not unless it is absolutely necessary. It is rock solid at 2300, but way to fast for my ability.

I will do some research on this, but could you tell me what I might be looking for? I am sure I have the gear ratio correct. But what is more puzzling that my transmitter at 40% throttle should not give 2300 rpm, something is bypassing everything. Perhaps demonic possession? Thanks

[georgi UK]

=] gear ratio is 46.67 for this heli. quickest route change the rpm1 to a lower setting and test, could be something on the input side is not being met? got a good connection to the motor wires, or the esc settings are wrong?

a log when you have one would be good......