Went out to test a NCR18650b (4S4P) battery pack we quickly slapped together in our floppy Skywalker (taken a lot of hard landings). Our hope was to get around 90 mins flight time. The wind was constantly hovering around 20kph, so we never really went for distance.

After some time in the air we got to 60km distance, then 70km, etc. At 90km we decided to fly the battery until the motor cut out, luckily it didn't - went to to 13.2V under load. 

Plane: Skywalker 2014 1800

AUW: around 2kg, not sure

Motor: Sunnysky 600kv X4108S

Prop: APC 12x6

Batteries: 4S4P NCR18650b 13600Mah

Battery weight: 812g

AutoPilot: APM2.6

Total Distance flown: 102km

Weather: Wind 20kph, sunny, 30°C. Altitude: 1634m ASL

Time flown: 129


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  • 300km

    @Weiliang That's a great tool. I couldn't get Mission Planner to convert the log file to csv to do any analysis, it was too big and crashed each time. 

  • @moglos, under flight mode, switch to Auto to eliminate the noise cause by plane on ground etc. 

  • 300km

    That exmaps link is cool. The distance of 305km agrees with what Mission Planner told me on screen. Google Earth only said 301. The exmaps value of 11m/s must have included that distance and some time on the ground.

    The mah per km value is interesting, but would change depending on battery payload. I flew with 4S7P. I'd have been 600g lighter with 4S4P. I did my calculations on km flown for different battery capacity/weights to recognise how the weight penalty plays off against the extra capacity.

  • @moglos, I see you have a 300km badge, so I got curious and found your log too. http://exmaps.com/2b5224 

    For comparison, you manage to do 72.8 mah/km , about 37% more efficient than Wesley's setup. 

  • Thanks Wesley,

    I played out your log, I see we are both in RSA :-)

    I so would like to organize a Drone Get Together, but distance does prevail here....

    My big XUAV Talon is flying quite well, probably not quite as efficiently as possible, but I'm kinda limited to hardware I have lying around.

    Still, I think I can do the 100K :-)

    And after that......, well I have this 30cc gasser twin engine, and a 2.6m beefed up glider wing, and a spare APM :-)

  • 100KM


    It was a simple 4 way-point mission, with a 5th way-point that was changed to a DO_JUMP command. Just enter the way-point which you want to jump to and the amount of times to execute the loop - in our case 55 times. 

  • Wesley,

    Did you have different way points for the corners?

    How do you set up such a repeat mission?

    I REALLY want to join the 100 Km club with my Talon :-)

  • 300km


    I would have thought the gradual descent might be due to change in air pressure during the flight, but that wouldn't explain it climbing on RTL at the end.

    The change in air pressure theory wouldn't explain why the logs show a gradual descent either. The plane would think it's still at 100m. Unless there is some kind of refresh between the barometer and GPS when you change modes?

  • congrats for this perfomance. i used the same batteries in 4P3S configuration (11.1V). i got 120 mins of flying with skywalker. the cruise was set to 47Km/Hr. so that means 94Km. i love this bird. my bird climbs 100m after i do RTL. although RTL altitude was set to 60m while planning the mission. any suggestions.

  • 100KM

    Thanks, the Exmaps output looks great, I can clearly see a gradual altitude drop of about 13m over the duration of the flight - wonder why this is? We had to RTL at the end of the mission, which was set to 100m before we uploaded the landing mission - hence the climb.

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