Plan
The plan today was to test a series of waypoints with different headings. I hoped to program the 'copter to fly between two points, pointing in a different direction each time. This would help with aerial photography, as I could then choose where I want to point the camera. It would also give me a feel for how accurate the compass is, if I pick cardinal points with clear landmarks.
Flight Log
I carried out two separate flights, both attempting to execute the above plan. Weather was perfectly still, 100% humidity, and about 30C.
Flight start: 11.46am
I accidentally had 'home' engaged during take-off. I flipped back to 'manual', and then to 'home' again, hoping to execute the waypoints. The 'copter flew to its first waypoint but hovered there without moving. Later, in the video, I found that it was pointing at the POI, rather than North, as I expected. I had programmed in a heading of '00' but apparently this causes it to use the POI rather than point at zero degrees - useful to know!
I set the 'copter back to PH/AH and flew it back to the point at which I had taken off. While moving it back, I found that Carefree mode made it actually more difficult to control. Perhaps I had moved from my starting point, or because it had moved to a 90degree angle to my starting point, the controls were not quite as I expected. In any case, I returned it to full manual mode, brought it back over the landing point and landed it very safely and gently,
Flight end: 11.48am
Flight start: 11.53am
The next flight, I was determined to execute the waypoint pattern and perhaps was not as thorough with my pre-flight check as I should have been. This time, I correctly set the switches on the controller ('manual', 'carefree on'), but I forgot to check the tightness of the nuts on the propellors. I also did not review the video of the last attempt, assuming that the reason it did not execute further waypoints was my mistake in starting with waypoint mode already on, but I should have realised that in that case it would have returned to the landing point, as that was the last waypoint on the list.
I calibrated, started the engines, and smoothly took off, then engaged waypoint mode again. The 'copter flew to its first waypoint but again hovered for a good twenty seconds without moving on to the next waypoint. I realised that this might be something to do with the altitude settings - that it would like to be at 50m, but that it could not get there, because the climb rate was too slow. (I had seen complaints of this on various forums). At this stage, I probably should have landed it and reprogrammed it with lower-altitude waypoints, but I was wary of being too close to the trees. Instead, I increased throttle to move it to 50m. It then moved to the next waypoint, but again hovered for ~ten seconds or so without moving, rather than the expected five. I assumed I was again too low, and increased altitude, but the 'copter did not execute the next waypoint. I realised in retrospect that I had probably gone too high, and again it was waiting to get to 50m before it could execute the next waypoint.
I decided at this point to abort the flight and return it to the secondary landing spot on the west end of the courtyard. I engaged PH/AH, reduced throttle, yawed around clockwise 360 to check responsivity, and began to bring the 'copter back toward the courtyard. At this point, one of the propellors flew loose, and the 'copter began to fly erratically. With PH/AH engaged, the 'copter was attempting to engage the motors in a way that it thought would keep it at constant altitude, but missing a motor, it began to descend, and also slew. For thirty seconds or so I fought this behaviour, until I realised what the problem was, and switched it to full manual mode. I then yawed it so that its back end was facing me again, and brought it back to the courtyard, and landed it again. However I was rather anxious at this point (I had nearly lost it!) and the landing was not perfect, so one of the stressed carbon struts finally broke loose.
Flight end: 11.58am
Lessons
The plan today was to test a series of waypoints with different headings. I hoped to program the 'copter to fly between two points, pointing in a different direction each time. This would help with aerial photography, as I could then choose where I want to point the camera. It would also give me a feel for how accurate the compass is, if I pick cardinal points with clear landmarks.
Flight Log
I carried out two separate flights, both attempting to execute the above plan. Weather was perfectly still, 100% humidity, and about 30C.
Flight start: 11.46am
I accidentally had 'home' engaged during take-off. I flipped back to 'manual', and then to 'home' again, hoping to execute the waypoints. The 'copter flew to its first waypoint but hovered there without moving. Later, in the video, I found that it was pointing at the POI, rather than North, as I expected. I had programmed in a heading of '00' but apparently this causes it to use the POI rather than point at zero degrees - useful to know!
I set the 'copter back to PH/AH and flew it back to the point at which I had taken off. While moving it back, I found that Carefree mode made it actually more difficult to control. Perhaps I had moved from my starting point, or because it had moved to a 90degree angle to my starting point, the controls were not quite as I expected. In any case, I returned it to full manual mode, brought it back over the landing point and landed it very safely and gently,
Flight end: 11.48am
Flight start: 11.53am
The next flight, I was determined to execute the waypoint pattern and perhaps was not as thorough with my pre-flight check as I should have been. This time, I correctly set the switches on the controller ('manual', 'carefree on'), but I forgot to check the tightness of the nuts on the propellors. I also did not review the video of the last attempt, assuming that the reason it did not execute further waypoints was my mistake in starting with waypoint mode already on, but I should have realised that in that case it would have returned to the landing point, as that was the last waypoint on the list.
I calibrated, started the engines, and smoothly took off, then engaged waypoint mode again. The 'copter flew to its first waypoint but again hovered for a good twenty seconds without moving on to the next waypoint. I realised that this might be something to do with the altitude settings - that it would like to be at 50m, but that it could not get there, because the climb rate was too slow. (I had seen complaints of this on various forums). At this stage, I probably should have landed it and reprogrammed it with lower-altitude waypoints, but I was wary of being too close to the trees. Instead, I increased throttle to move it to 50m. It then moved to the next waypoint, but again hovered for ~ten seconds or so without moving, rather than the expected five. I assumed I was again too low, and increased altitude, but the 'copter did not execute the next waypoint. I realised in retrospect that I had probably gone too high, and again it was waiting to get to 50m before it could execute the next waypoint.
I decided at this point to abort the flight and return it to the secondary landing spot on the west end of the courtyard. I engaged PH/AH, reduced throttle, yawed around clockwise 360 to check responsivity, and began to bring the 'copter back toward the courtyard. At this point, one of the propellors flew loose, and the 'copter began to fly erratically. With PH/AH engaged, the 'copter was attempting to engage the motors in a way that it thought would keep it at constant altitude, but missing a motor, it began to descend, and also slew. For thirty seconds or so I fought this behaviour, until I realised what the problem was, and switched it to full manual mode. I then yawed it so that its back end was facing me again, and brought it back to the courtyard, and landed it again. However I was rather anxious at this point (I had nearly lost it!) and the landing was not perfect, so one of the stressed carbon struts finally broke loose.
Flight end: 11.58am
Lessons
- I didn't manage to thoroughly test the functionality I wanted to test - i.e. pointing in different cardinal directions while moving - because the very first heading I used, 00, caused the kopter to point at POI. I will try 360 next time, and perhaps 01.
- Altitude control is tough, and if the 'copter needs to be within a certain altitude in order to execute the next waypoint, then it's crucial to either
- get better at using the MX-20 transmitter display so I can read and adjust the altitude quickly
- use a lower altitude so I can more easily see whether it is too high or too low - at previously tested altitudes of 10--30m I had none of these problems
- figure out how to get the 'copter to completely control its own altitude - in the firmware documentation there is a good discussion of this
- Slewing clockwise may be a particularly bad idea and cause propellers to come loose - always slew anticlockwise.
- A pre-flight-check needs to be designed and more carefully attended to.
- Bring lots of spares - and investigate the issue with the struts.
