I attempted my first flight tonight with my APM. It was an incredible struggle to keep the plane aloft and ended in a very rough landing. And this took place while in manual mode, which I thought I understood to have no logic from the hardware (however the entire flight felt like I was fighting the hardware to keep it in the air).
I wondered if someone could tell me what to look for in the logs or tell me where I went wrong. I believe I have attached the correct log files and apologize if I haven’t.
According to the log, the APM copied your inputs to your outputs, as it should in manual.
See the attached image, where I plotted input/output for Ch1(Ail), Ch2(Elev) and altitude.
This suggests that there is something wrong with your airframe, and it probably would fly the same without the APM in the loop.
Another oddity:
In your log file it looks like you did not move the sticks during radio calibration.
RC1 - RC8 have values for Min and Max very close to 1500 which is normally center stick.
This would not have any impact while in manual mode, but selecting any other mode would likely lead to problems.
Sorry, I missed the fact that you uploaded another log.
My previous post was based on your first log, which looked like it contained a short flight up to ~30meters.
Your second log does not appear to be from a flight, and it looks like either the TX or the RX was off as all RCIN values are constantly 900.
[quote=“JNJO01”]According to the log, the APM copied your inputs to your outputs, as it should in manual.
See the attached image, where I plotted input/output for Ch1(Ail), Ch2(Elev) and altitude.
This suggests that there is something wrong with your airframe, and it probably would fly the same without the APM in the loop.
Another oddity:
In your log file it looks like you did not move the sticks during radio calibration.
RC1 - RC8 have values for Min and Max very close to 1500 which is normally center stick.
This would not have any impact while in manual mode, but selecting any other mode would likely lead to problems.[/quote]
Thank you very much for your help. What program did you use to plot the log because I would like to understand this as much as possible.
I have flown that airframe (horizonhobby.com/products/p- … nf-PKZ1880) many times in the past, however adding the APM and wires could have made more of a mess with weight and balance that I predicted. I know that the airframe isn’t the best choice but I wanted to use something that I would be heartbroken if it was destroyed.
I used MissionPlanners built-in log analyser.
There are several others, and I can’t say if one is better than the other.
You first logfile contained several “spikes” in the data, which made it hard to graph the data.
I edited out most of the data before and after the flight.
The logs are editable with most text editors. I prefer Notepad++, which also displays line numbers.
More on log-analysis can be found here: plane.ardupilot.com/wiki/downloa … n-planner/
That’s more geared towards Copter, but it’ll give you a place to start.
