In this first video you can see everything go properly at first, I flip directly into UI1 which is supposed to be 1700rpm. Then at about 20 seconds in, I flip to UI2 which is supposed to be about 1900 RPM but holds it at around 2000, but is surging back and forth between 1900 and 2000 or some times more. Gov response is 5 and holding is 1 or 2 in this video, holding limit is 70. The entire video past 20 seconds is the same idle up mode (supposed to be 1900rpm).

https://www.youtube.com/watch?v=Y58PixEfrhU

In this second video I flip directly into UI2, and instead of holding the requested 1900, it holds it at 2000-2040, but then at around 30 seconds in, it goes down to 1900 on its own, it was in UI2 the entire time. However notice that the engine is not surging like it was if I went to UI1 first, and then into IU2.

https://www.youtube.com/watch?v=6WACm-O-en8


I have two sensors installed in the helicopter right now so I can switch between them easily and see if one is bad. Both are doing the same thing. Both are positioned as perfectly and close to the magnets as possible.

Thank you for the details. Very soon we will have more or less same helicopter for testing.

From the videos it look like the Governor was not engaged then it is trying to find the requested value. Is it visible that Governor was engaged in the Flight log right at the beginning?
I guess that yes.

_________________
Spirit System developer

I do not have logs from these videos but from testing within the last month I have a log that just says governor was engaged when it was doing similar or overshooting. And not a single 'rpm too noisy' or anything else.

Just engaged and good health, and a few saying vibration is very high.

I am trying to address vibration issues, in these flights it was showing 120% almost constant in telemtry for output. Last year at ircha on 2.8 firmware it only read ~10-25

I'm currently going through both my nitros trying to figure out what could be causing this and why the goblin nitro seems to be working properly.

One thing I have noticed is that, in a video from last year (https://www.youtube.com/watch?v=BE3aS-d ... zZEvadnUwc) I noticed that the telemetry throttle % is the actual throttle value the governor is using correct? If so, when at 64% throttle it was in this video around 1900 (0:38 seconds) and once it was at 65% it was hitting 2040rpm. If that is right the unit may be having a hard time with that spot if there is no resolution to get any rpm in between. I don't know why.

But also when I flip into IU3 (supposed to be 2000) it his shooting up to 2100-2150 some times instead.

The servo on my goblin is an align BL855H tail servo, something I noticed is that it has 100us more resolution from 0-100% throttle than the KST bls815 on my 700N. (970us vs 870us).

Either there is something with my carb causing something strange around 65% throttle or something is with the spirit unit. I have a spirit II coming next week I will try swapping a different unit onto this heli and I have another servo coming as well to rule that out. I have gone through the engine about ten times. I replaced the regulator diaphragm. I replaced every seal and o-ring on the entire engine. Three different check valves and a few different glow plugs. New tank. All new fuel lines. New clunk.

I noticed that the RPM readings in the software seem to only read in factors of 7 or 5, is there a chance that for some reason with the way the governor works, it does not like a perfect 8:1 gear ratio? I believe the goblin is 8.25:1 or something similar (8.23?).

As of right now the goblin is confirmed working, even with Response 5, holding 3, and holding limit 80. Same engine, YS 96srx. No surging even with the engine quite a bit richer than my 700N.

Thanks a lot for additional info.

The reason for 64/65% difference could be just because motor has different environmental parameters. For example it is colder vs hotter.
Then to get same RPM it might be necessary that servo is at 55% and other time at 65%. This is similar to Electric helicopters when battery is charged vs discharged.

Vibration measurement is completely different between older firmwares. So very likely they were that high also previously.
It is showing approximately same value that you will get with Spectrum Analysis in the Spirit Settings.

_________________
Spirit System developer

I swapped a spirit II onto this helicopter to see if my older spirit pro was the issue.

IU1 was supposed to be 1700rpm, but it held 1800 instead according to telemetry. IU2 was supposed to be 1900 and it held 1900 correctly. IU3 was supposed to be 2000 and it started surging up and down as soon as I flipped into it hitting 2100 at the top of the surges.

I think the problem must be somewhere else, I have already checked everything over, replace all lines, clunk, checked for any leaks, muffler seals, replaced every seal and o-ring in the engine, changed RPM sensors, check valves, glow plugs, etc. I have absolutely no idea what there is left to try.

Is same throttle servo used in these helicopters?

_________________
Spirit System developer

No - the goblin nitro has an align BL855H tail servo on throttle, and the 700N has a KST BLS815.

I bought an align BL750H tail servo to try swapping out the KST to see if that helps but haven't swapped it yet. The KST works perfectly on the bench, even when pushing on it at all positions in the range of motion, I have no obvious reason to believe it is bad in flight, but I will check.

The governor, was at one point, working properly on this helicopter, at the end of 2017.

I currently have it apart and am going through everything once again. I will try putting a new clutch liner and changing the one way bearing, though I do not see any evidence of those parts being bad, that's all there is left to try (no tail kick or headspeed loss on pitch pumps, tic tocs, etc.)

I presume your latest test was with response 5, holding 3. What about when holding is set to 2 or 1? The 96SRX in my 700NDFC surges when holding is any higher than 2. The rpms are like a sine wave - you can hear it when the model is in a hover.
I used to have an os105 in the same model and same thing.

It was response 5, holding 2 today.

I did not try putting it back down to one for holding. It is strange that holding gain is so sensitive on this engine, because a few firmware updates ago I was able to almost max out holding gain without this issue.

The previous time I tested I was having surging even with holding gain at 1 though. This surging is new, I had issues with it holding the incorrect RPM for a long time, but the surging is new as of this year.

On my goblin I am at response 5, holding 3, no surging at all, and it is locking into the correct RPM's. I cannot at all explain why the 700n will not lock into the correct RPM's a lot of the time. Why is it locking into 1800 instead of 1700, or 2040 instead of 1900, etc. Sensing divisor and gear ratio are for sure set correctly...1 magnet 1 divisor, 8.00 : 1 gear ratio.

I will try maybe unplugging my 4649t to see if it's contributing to the strangeness. Maybe it is telling the spirit throttle is at a different value than my sats are. If something like that is even possible. It doesn't link up to my transmitter half the time, but I suspect the firmware needs to be updated.

With such low holding gains, is it working well for you in actual flight? How are loops, hurricanes etc.?

I changed the throttle servo today to an align BL750H tail servo.

Gov is holding correct RPM's for the first time, no surging, all issues are gone.

Case closed.

I have no idea why as the KST worked flawlessly on the bench, I could not get it to fail or do anything weird. I wish I had tried changing the servo two years ago, I cannot believe the amount of time I've spent chasing these issues.

Oh well, I'm just happy it works, and Tomas, the governor works very well now. No need to change anything.