100 KM Mapping / Video conservationdrones


Introducing the new 100 KM long range Mapping / Video conservationdrones base on Skywalker air frame. With the new power system, the flight duration is more than 3 hours and range over 120 KM with 200 grams payload, typical weight for point and shoot camera such as Canon S 100 GPS on board. The all up weight of the drone is 2.9 KG ready to fly.

About 18 months ago, I've achieved 100 KM with FX 79. But it has never put into practical use in the field. The main reason is with the required batteries on board, if I put payload , such as camera in front, I'll need to add weight at the rear end to get the plane balance. The total weight will be about 3.7 KG and hand launch become very difficult and dangerous. landing a heavy plane at confine area is another challenge. 

I have tried a few combination but non of them meet my requirement until I found the current power system. The major breakthrough is the new Lithium Ion battery pack which rated at 3 C continuous discharge. According to supplier, it use imported LG Lithium Ion battery and the pack is assemble at their partner factory at China. 

The air frame I use is the proven Skywalker 2014 1800 mm three piece wings model. I think other version of Skywalker should give similar performance. The motor is SunnySky 2820 800 kv match with APC 12 x 8 electric propeller. With this set up, you'll need to limit the top end power via Mission Planner to limit the full throttle at about 26 Amps, which give more than enough power for take off and climb to altitude. Once enter cruising mode, the average amps draw is only about 5 to 8 Amps.

The 100 KM attempt took place at my local flying field. It was a sunny Sunday afternoon with some winds. Load the fully charge 4S 21000 mah Lithium Ion battery and some basic set up, it was ready to go. Because of the light weight ( 2.9 KG ) of the plane, I was able to hand launch it with my left hand while using my right hand to hold the radio transmitter. Take off was effortless and after climb to about 60 meter, I switch to RTL mode to test the auto pilot and climb to mission altitude ( 100 meter ). Once everything seems fine I switch to Auto and start the mission.

Three hours and 5 minutes later, It has travelled 117 KM with 29 % battery capacity remaining. As it was getting dark and it actually completed the planned mission, I decited to land. If there was enough time, when push to the limit, I think it can travel another 25 to 30 KM or 40 to 50 minutes. But for general mission flying, it is always good to have about 25 % of reserve capacity for better battery life cycle and prepare for unfavourable weather condition. Another issue need to consider is camera battery life. Most camera will not operate for more than 2 hours without extenal power supply.

3689677922?profile=originalThe lithium ion battery I used can charge with normal Lipo charger at 1 C rate, but the discharge curve and minimum voltage is difference from Lipo battery that we all familiar with. When high power was loaded, such as take off, the voltage will drop significantly. In my case, the freshly charged battery voltage reading is 16.97 volt. During take off at full power, which draw 25 Amps, the voltage drop to 15.6 volt but once enter cruising mode, it bounce back to 16.4 volt or so. For air plane, it is safe to discharge down to 3 volt per cell or 12 V for 4S pack. If you push to the limit, It can hold up well until 2.8 volt per cell, after which, the voltage will drop fast. You will need to change the low voltage cut setting of your ESC to LOW or change the battery type to NICD/NIMH to avoid premature power cut off by the ESC.

Unlike lithium polymer battery, once the Lithium Ion battery discharge to very low voltage, say 2.4 volt per cell, it can bounce back to about 3 volt if you cut off the power for a while. If you are flying FPV and fight for the last KM to reach home, this technique and the characteristic of lithium ion battery may save your day or at least get it closer to you.

With 100 KM range, the new long range conservationdrone open up the posibility to map or video area that is previously unreachable by normal drones due to unaccessable suitable take off / landing area. It will also suitable to long range river bank ripirian area monitoring or border patrol or any other mission that require long range flight and long flight duration. Flying at 300 meter, it can also map 1500 Ha at about 10 cm per pixel resolution, which make large area mapping possible with a single flight. The camera will need external power.

3689677975?profile=originalBelow is the specification and parts components for the 100 KM Skywalker conservationdrones. Any experience drone builder can build it with the available information. 

Air frame : Skywalker 2014 1800mm 3 piece wings
Auto pilot : HK Pilot Mega 2.7 master set
Radio control : Futaba T 8 J
Telemetry : HK Pilot 915 air. RFD 900 ground
Motor : SunnySky 2820 800 kv
Servo : Hitec 65 HB
Propeller : APC 12 x 8 Electric
Battery : 4S6P 21000 mah Lithium Ion
On board sensor : Canon S 100 GPS

Here is the link for the tlog of the 117 KM flight. From the tlog, you can view the complete flight mission as well as extract parameter from it. Use it at your own risk as some setting may be difference from user to user. 


Here is the KMZ file 


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  • @ Keeyen 

    The power requirement to spin the propeller will be the same. As the cell voltage drops the current draw will have to increase in order to meet the same amount of power. P = I x V

  • @Daryl, 21000/6=3500 mAh. Only parallel cells increase the capacity of the battery.

  • Darius Jack, Thanks for the info on the heat issue.

    However I think your missing something huge based on your continued talk on Li-Po batteries from your response to me and a few others above. 18650 lithium batteries batteries offer a huge capacity vs weight savings compared to Li-Po batts in UAS systems that can work with the lower amp draw limitations. In most cased its greater than 45% more energy density for the same weight. 

    check out a youtube channel called MyGeekShow, he has a video explaining this.

    also check out a 300km flight posted to DIYDrones about a 300km almost 7 hour flight of a Cyclops-E (copy of a Hobby UAV Techpod) flown with a 18650 based battery pack.

  • @Daryl,

    higher capacity 18650 cells have shorter life-cycle since alike chemistry is packed

    within the tube of the same volume, so fast charging , fast discharging is an issue, generating more heat.

    Tesla applied cooling fans to get individual Li-Ion cells within battery pack to work within factory set  safe operation temperature limits.

    Li-Po batteries are manufactured as a single long belt, cut to pieces, so there is no need to build multi-P pack from individual Li-Po cells P-connected like in case of Li-Ion cells, since a longer Li-Po belt  delivers higher capacity by itself.

  • Am I doing my math wrong? 4S6P 21000mah of 24 18650 batteries only yields 875mah per battery. Even if the 21,000 mah is 75% of the cells rated capacity for safety reason that is only 1166mah per batt. If that's all correct you could definitely get more range with higher capacity 18650s without taking up more volume at a slight weigh increase. Someone correct me if I'm wrong, I'm new to the 18650 cells.

  • @Keeyen,



    Li-Ion battery packs are generally not fit for drones, much heavier than Li-Po (metal tubing extra weight), limited individual cell capacity due to its size.

    Building multi-P multi-S Li=-Ion battery pack requires smart balancer board to be wired, 

    temperature sensors and charging current, discharding current limiters to be wired.

    A new Li-Ion battery pack can work fine and you get higher voltage in open circuit and lower in closed circuit as exactly with any battery pack (automotive car Pb battery).

    Individual cells should be preselected against internal resistance and general performance.

    None-balancer board soldered multi-P multi-S Li-Ion battery pack can easily deteriorate after few charding/ discharging cycles.

    So be aware of Li-Ion battery packs none-balancer operated.

    I have tested tens of used Li-Ion packs and resistance of individual cells very greatly

    and some get hot very fast and other stay still cold , so I use used Li-Ion packs for tests and use them with LED lighting but never head of 1C charger for Li-Ion cells or battery packs if  thermal protection and smart balancer are not built-in.


    Smart balancer, smart charger, temperature sensors can double the price of your Li-Ion battery pack so don't buy individual cells to get pack soldered on your own.

    You need to get access to large number of Li-Ion cells to preselect them first.

  • 100KM
    I'll need more test to observe the behavior of the Li Ion battery. From the few flight with It, I notice that the Amp goes higher when voltage drop. Higher Amps means more current drawn so it may contribute to lower flight time. I also notice the internal resistance is significantly higher compare to Lipo. Mine is about 7 to 8 OHm. My Tarot 810 draw about 25 Amps in hover or slow forward fligh so it only draw slightly over 1C.
  • @Cala

    Li-ion batteries can store around 50-75% more energy than Li-Po but if you draw Li-ion batteries more than specific C they are going to give less energy, e.g if a a Li-ion is rated 3400Mah with 0.5C if you draw 2C you are going to get less than 3000mah.

  • Thank's Keeyen for confirm.

    But if you compare the same weight in batteries, you have more energy in ion, near double? Don't you have notorious increasing in flying time? (I don't have experience with ion, or I'm in a mistake?)

  • 100KM

    Mission Planner > Flight Data > Telemetry log > Tlog > KML or Graph > Extract Param

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