Hi everybody - The AH on my MK (HW: 2.5 SW: 2.06) works very nicely when the copter is parked - but even during slow moves it is descending quite a lot. Then once I stop the move and return to a hovering position (without any throttle stick input) it will return to the original AH elevation. I haven't touched any of the AH settings so far and was wondering if anybody has any input on how to fix this problem? Thanks!
Hello Tim, Check out this topic: http://forum.freeflysystems.com/ind...-problem-with-mk-fc-2-5-and-bl-ctrl-3-0.3918/ What are the details of your copter? Can you send a picture of your stack? If the vibration dumpeners are too soft, it can effect the AH performance. Try replacing the FC board on hard vibration isolator.
Thanks for sharing this Ozkan. I am running the MK FC 2.5 with i2C converter and Castle ESCs, Tmotor 4012-09 motors and 15x5 Xoar props. I was running it as a flat 8 set-up for a while and the AH seemed to perform really well. With one of the last firmware updates and the change to an X8 the AH accuracy suddenly changed. As I haven't changed the way the FC is mounted, I'd doubt that its caused by the vibration dampeners but I'll give it a try
As far as I remember, one of the members here faced the same problem with I2C converter, but don't remember how he ended up. If it's not related with the hardware, it's the settings since you say it was good with flat Okto. You might want to change two settings to try: Barometric D and Min gas. Min gas depends on your hover gas. If you are hovering with %50 gas stick, this means your hover gas is around 127. So make this 30-40 below your hover gas. If your hover gas is, lets say, around %50, then the min gas can be around 80-90. This setting had much more effect on FC 2.1 version. I also would recommend to raise the Barometric D value to 50 for tighter AH.
I know this is a old thread.. But did you guys solve the AH-issue? I'm facing the exact same problem, having the FC 2,5 and Herkules III setup. AH is good as long I don't fly anywhere. As soon I'm moving the kopter it's start sinking. I have done all the changes as suggested in this thread. No luck..
Bo: Check that you have the foam cover and/or some kind of gust filter on the FC pressure transducer. What's happening is that the motion of the copter is causing a drop in apparent air pressure around the FC -- which it indicates as a sign that the copter is ascending, so it powers back on the throttle a bit, and, of course, that actually causes the copter to descend. Andy.
I'm not sure that more foam will help. If you're using larger than 14" props it might possibly be that they're causing more turbulence close to the FC and that's misleading the pressure transducer into thinking the copter is ascending. It might be a question best answered on the forum at mikrokopter.de -- just to see if anyone else has had the problem and found a workaround. Andy.
Bo - I had this exact problem, funnily enough, with nearly the same configuration. I've close to tuned it out with the min. gas setting, however it's not perfect and does lose altitude during forward flight, particularly at speed. I generally don't fly with alt. hold near to the ground, and just work with the drop of about 2-3m when I am using it, until it recovers after the move.
I went through all this as well. Holger said to check the foam and sensor. They he said to make a small cover over the sensor. Then he asked me to make a make-shift cover over the electronics and nothing worked. I switched FCB's and it improved but still not to the point of the flat 8. I then switched the X8 back to flat 8 and it completely went away. IMO- Something in MK tools is not plug and play with X8 in heavier lift applications. I know that it's worked in some mid lift applications but I think you need to do a bunch of tweaking to get it right and the bigger the motor the worst it gets. Just my 2 cents.
Overall power, is necessary for the AH performance to hold true, the efficiencies from a flat 8 to an x8 are more different than I originally estimated, so while you may have enough thrust of the same AUW in a flat configuration the numbers change a lot going to an X. In the X configuration depending on your AUW you may no longer producing as much thrust.
I haven't ran the X8 since August because I got such great results with the flat 8 but I ran the same size props in both combinations. I ran Tiger 16X5.4's on top and bottom of the X8 and also with the flat 8.
Interesting theory but my problem didn't matter if I had a payload on it or not. Going from straight 8 to X8 my hover throttle changed from 60% to 66% when flying the red camera. The problem was the same (for me at least) with no gimbal.
Thank´s for your input. The problem is only present in AH mode. I'll try to tune the dynamic stability, to see if it will make any difference... @ Cam - What number did you end up with at min. gas? I'm at 90 and I only see little or no effect.
My setup still has the problem, but the newest MK firmware helped a bit; it's better than before. I have adopted myself to use just a little bit gas while using AH and forward flying.
I just came back from the Alps with a odd experience. In higher altitude - around 900 m. above sea level - the X8 sits a bit more heavy in the air but AH holds perfect with the all the same settings....?
That's interesting Bo. Obviously the air density is much less at 900m, but I'm surprised it would make that much difference. Andy.
@Bo I've changed to some bigger motors and bigger props and the altitude loss has definitely come back with a vengeance. I think Andy is on-point here with the barometer being subject to some turbulence from the Co-Ax setup. Formulating ideas for some sort of fabric or 3d-printed wind break around the MK stack to see if it changes how AH works.