100KM Challenge


Graham, Myself and the pilot Ryan after the successful 100+ KM flight

It seems to fly for a distance of 100 KM with our electric air plane equip with APM or so is a norm now a day. Someone even suggest to rise the bench mark to 150 KM as the entry level for long range challenge.

A few months ago, I gave it a try with my Skywalker carry 2 piece 6S 5000 mah battery in parallel. It travelled some 80 km before the ESC cut because of low voltage protection. Although the attempt was fail, but I learn some lessons. The first lesson was, it is not as easy as I think.

Skywalker is a little draggy by design, facing a strong head winds, sometimes it's ground speed will drop to a few KM per hour. It is struggling in windy condition and unfortunately, this is the condition where we usually have to deal with in tropical area. With the two big and heavy battery in the fuselage, it is also very difficult to find space for our mapping camera. But don't get me wrong, Skywalker, especially the 2014 version is a very capable air frame for what I consider mid range ( 20 to 30 KM ) mission.


Recently I read quite a number of good report of the Zeta Science FX 79. Being a flying wing design, it has a lot of space for battery AND my on board equipment. The removable wing also make this huge wing ( 2 meter wings span ) become very easy to transport.

For this 100 KM challenge, my set up is :

Zeta Science FX79
APM 2.6 external compass
3.02 firmware
Analog air speed sensor
2 pieces 6S 5000 mah battery in parallel
T motor 3110-470
APC 12 x 8
CC Edge 50 A
attopilot current sensor
Savox 257 servo
3DR 433 telemetry.
Futaba 10C radio system
All up weight : 3.4 KG


I start the flight in the afternoon in windy condition. According to APM, the winds blow at 10 to 30 KM per hour in east or north east direction. It is certainly not a favourable condition to go for the badge but I would like simulate the actual flying condition for our usual mission.

Launching a big and heavy wings need a little caution, I wear a welder grove to protect my hand from the hungry rear propeller. With my power set up, take off is quite easy with a little head winds. After some minor trim and it start the mission.

The flight path was planned along our local Sandakan Turf Club race track. The distance of the track is 1.4 KM. This will be easier for me to confirm the total distance after the flight. I also plan it to fly at 100 meter hoping for calmer condition at lower altitude.

APM 2.6 and the latest 3.02 firmware was rock solid throughout the whole flight. After 78 rounds and the battery voltage drop to below 20 volt, I terminate the mission. After some simple calculation, it was 109 KM and APM show slightly more. The whole flight duration was one hour and 57 minutes.

My next target now is 150 KM WITH reasonable extra payload. After all, no point for us to fly for hours and come back empty handed.

I would like to thank Prof LianPin Khoo, Prof Serge Wich, Simon and Brenden of conservationdrones for their encouragement and technical advise. I also want to thank Graham who came all the way from Medan, Indonesia to have a great time flying together and tune up his conservationdrones Maja. He make the two long hours a lot of fun. Special thanks to the Arduplane development team lead by Andrew Tridge. Without all their hard work, we are still confine to fly a few hundred meter from us for fun. Thanks guys.

Here is the link for the tlog.




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  • nice! will inspire me a lot now!...

  • Hi Keeyen, 

    congratulations to 100km,

    I 'm trying to fly fx 79 as well , and I had difficulty getting its parameters , can you give me the parameters ?
  • Hey Keeyen,

    I want to fly 100Km in a straight line, what could be done for this.

    Please respond ASAP.


  • 100KM
    Hi Arga
    I think it is possible but the plane will be heavy. Unless you have good flying skill and landing area, it may not practical. For my normal mapping mission, I fly for about 50 minutes with a Canon S100 on board without gimbal.
    If you really want to go for 90 minutes flight endurance, may be you can have a look at My Twin Dream air frame.
  • Moderator

    Well done! Welcome to the club :)

  • Hi keeyen, very interesting result of your plane.

    I'm about to built a plane targetting 90 minutes of flight time carrying a sony nex 5 with flatmap gimbal for mapping if possible. I want to attach a parachute for additional landing option on the plane. 

    From your experience, do yout think it will be achieved on fx79?

  • Hi...log link has broken. Could you send me the log file please...


  • Congratulations on your 100km flight. I fly a Skywalker X8. There are about the same size but the FX-79 would be shorter to carry around with its shorter detached wings. 

  • Spread battery weight to the wings. Reduces flexion at wing roots, reduces drag and improves room accomodation in fuselage. If you have auto control pilot, you can make airframe unstable and reduce drag, though electrical control inputs will increase reducing endurance. You only have a certain number of control inputs available per flight, a give and take. Ideally some kind of solar generator to support that would make sense, but solar is weak.
  • Congratulations!

    Great Job :-D thumbs up for you Keeyan

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