Why won't the motors start. Class G airspace, no restrictions.

[joeruby]

I was in class G airspace trying to fly a Litchi mission with my "new" ( low mileage - 15 miles) P3P called "Maxwell" (I had just flown a mission at home the day before.) This was a new flying area for me. I was on green grass in the open. I uploaded the mission and everything went OK except the motors did not start. So after a few seconds I tried to start the motors manually and they would not start either. I have attached a link to the DAT 471 file from the AC. I would like to understand what went wrong.

After trying to start the motors manually, I decided to reboot everything. (Fixes Windows sometimes - ) I also decided to pull the battery out of the AC too. I know that the battery was all the way in and locked, as I always check this. Anyway, the reboot solved the problem and I had two perfect Litchi missions up the side of the mountain to about 1,000 feet above takeoff (150 feet above the ground all the way) It was exciting to watch the FPV as the AC climbed at 15 mph ground speed! To bad the camera was facing the sun, so the video wasn't really usable. This was just a test flight for Maxwell. (KAOS has been retired at 644 air miles.)

Why didn't the motors start on the mission or manually?

See photo plot:

Dat file 471 link:

Dropbox - File Deleted - Simplify your life

www.dropbox.com

Thanks
Joe
KC7GHT

 

[Fly Dawg]

This appears to be why:

 

[joeruby]

This appears to be why:


View attachment 112942

Wow! What a surprise. This AC flew fine yesterday. Then I went over to the new location, expecting everything to be OK and I had the no=start problem. I simply turned everything off, and then everything worked perfectly. Two perfect mission flights and some manual flying - all OK. That was a flight to give me more confidence on the new AC Maxwell. Instead it has caused more concern. Any more comments/data would sure help.
Joe
KC7GHT

 

[joeruby]

This appears to be why:


View attachment 112942

Fly Dawg, I am trying to follow you. Where/how did you find this data. I converted the DAT file to .csv and looked at the csv file with Excel, but I did not see this info. Maybe a another hint/ Thanks.

 

[sar104]

Fly Dawg, I am trying to follow you. Where/how did you find this data. I converted the DAT file to .csv and looked at the csv file with Excel, but I did not see this info. Maybe a another hint/ Thanks.

You need to look in the event stream. If you converted it with DatCon then choose the Event Log File option, which creates a txt file containing the event stream.

 

[joeruby]

Thanks sar104.

Now that we know that "The compass is stuck" and the motors won't start, and it all cleared when I rebooted everything, is there anything else we can gather from this episode? Will the motors start next time and the mission get underway and then have the compass fail mid-air probably causing a crash? The aircraft is bran new (two years ago) with only 15 miles of fight time. This is now my main aircraft. Everything seems to work OK with the two successful missions right after the stuck compass.

 

[sar104]

Thanks sar104.

Now that we know that "The compass is stuck" and the motors won't start, and it all cleared when I rebooted everything, is there anything else we can gather from this episode? Will the motors start next time and the mission get underway and then have the compass fail mid-air probably causing a crash? The aircraft is bran new (two years ago) with only 15 miles of fight time. This is now my main aircraft. Everything seems to work OK with the two successful missions right after the stuck compass.

I've not seen that stuck compass message before, so I don't know what might cause it. The magnetometer data in the DAT file might give a clue - did you check those?

 

[Thomas Gilmore]

I am just curious. When you changed locations, how far were they away from each other? From what I understand is if you move a certain distance away from a previous flight, you need to recalibrate the compass. You never mentioned if you did that. Just curious.

 

[N017RW]

I am just curious. When you changed locations, how far were they away from each other? From what I understand is if you move a certain distance away from a previous flight, you need to recalibrate the compass. You never mentioned if you did that. Just curious.

Tom,
That advice is no longer suggested by DJI.
Interestingly, it was never necessary

I have a P2 with no camera which I still fly as a Sport aircraft.

It has not had the compass calibrated in over 4 years and has been flown as far away as 600-700 miles from the cal. location.

Calibration (compensation) is used to model and then compensate for the magnetic distortion(s) created by the ferro-magnetic items ON the aircraft not in the location it is operated.