Anatomy of a 301 km Flight

Today I flew my Cyclops EPO for an incredible 7 hours and 8 minutes, covering 301 km (301 km !!!) in one flight.

After flying my Maja for 126km I decided 200km would be my next challenge. I got the Cyclops with that in mind, it was very very efficient straight out of the box and after my first flight test I realised it was capable of much more.

I did 5 flight testing sessions where I tested different speeds, C of G positions and propellers. The data from my last two sessions suggested 300km was possible with good conditions so that became my goal.

I planned my mission with a couple of waypoint path options that I could switch between using do_jump. After a hand launch I switched to auto for a very gentle climb reaching 50m of altitude over about 2km. I flew a few laps of a 2.5km lap, before switching to a 3km lap and then a 3.5km one which used a do_jump command to fly continuous laps at 60m altitude.

To monitor my progress I’d made battery consumption schedules for 250, 280 and 300 km. My calculations said that I would need to run my batteries down to 10% remaining to reach 300 km. The first half of the flight was very calm and I was ahead of schedule. But the wind picked up in the afternoon and it became apparent that I might finish with less than 10%. I tried to help the situation in the last hour by varying my speed around the lap. I flew at 14 m/s for the head and cross wind sections, and dropped to 13 m/s when I had a tail wind. I hadn't done any calculations to support that, it just seemed that I could make the most of the tailwind section by dropping my power there a little.

I’d decided in advance to end the flight when the battery dropped to 12 V (3.0 V per cell) and I could see as I passed the 280 km and 290 km milestones that it really was going to be tight. The voltage was hovering either side of 12 V as I approached the 300 km mark so I knew it was time to bring it in, but I also knew that Mission Planner can underestimate the distance compared to the GPS log. I decided to fly to 303 km to be safe. The way the laps worked out it was 305 km when I hit the ground, and just as well because the GPS log came up as 301 km. If I’d come in when Mission Planner told me 303 I would have been member of the 299 club.


The telemetry log file is 47 MB (linked below) and Mission Planner crashed when I tried to create the KML file (I tried on three different machines). It did manage the GPX file thankfully.
Key specs:

  • Cyclops E with V-tail
  • APM 2.5
  • Panasonic 18650B Li Ion batteries. 4S7P, 23,800 mAh
  • Aeronaut 11x9 prop
  • Hobbyking telemetry
  • Distance covered: 301km (according to GPS log file, 305 km according to Mission Planner)
  • Flight duration: 7 hr 8 min 10 sec
  • Average groundspeed 41.7 km/hr

Log File (47MB)

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  • Notepad++ on windows should do it.

  • 100KM

    Hi Bill.  Can you suggest a method for Windows?  Otherwise, I'll search when I get home.  Thanks.

  • Developer
    You can easily just chop the tlog file up into smaller sections. It has no real start/stop in the file. You can use split command on unix to do that.
  • I completely agree Wayne and it should be a simple case of taking your design patent to the relevant authorities so how about letting Moglos's fantastic achievement be the hero here.

    Yes the design did play a part however the take home message is Moglos's meticulous testing, planning and execution of the flight. The technical achievement of optimising the battery, power train, autopilot and airframe is what is the learning experience is for the rest of us.

    I have already taken information from it for our long range electric aircraft and I am grateful for Moglos's posting.

  • 300km

    Yes Wayne has made a claim to YouTube to have my video removed. I'm writing him a private message to try to resolve the issue.

  • Congratulations moglos!!!

    you open the doors for the next level in flight endurance in diy uav community, the video link is no longer available, could you please post picture of your plane and onboard equipment installed?

    Congratulations again

    Best regards.

  • 100KM

    @Ryan, I second that. I thought about turning down the sampling rate for my long flights, but if something unexpected were to happen - like a crash - we would want to be able to analyze the details.

  • It sounds like it is time to request an improvement to the Mission Planner that saves the log file in a multi-file format instead of one big file... or does it do that already?

    Like, save every 1MB, or save every 5 minutes.. .something like that. 

  • 300km

    @ Steve - I had company virtually the whole time. I'd asked I couple of FPV pilots to come down to film the flight. They had fun chasing the Cyclops around the circuit, and then chasing each other. They stayed all day. Plus another five or so pilots that came down independently to fly (thank you for tolerating us being parked right beside the runway).

    @ clearskiesph - Hacker A30 52S UAV 

  • Congrats.

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