Soaring With The Sun: 4 Years Of Solar RC Planes

Many of us have projects that end up spanning multiple years and multiple iterations, and gets revisited every time inspiration strikes and you’ve forgotten just how much work and frustration the previous round was. For [Daniel Riley] AKA [rctestflight] that project is a solar powered RC plane which to date spans 4 years, 4 versions and 13 videos. It is a treasure trove of information collected through hard experience, covering carbon fibre construction techniques, solar power management and the challenges of testing in the real world, among others.

Solar Plane V1 had a 9.5 ft / 2.9 m carbon fibre skeleton wing, covered with transparent film, with the fragile monocrystaline solar cells mounted inside the wing. V1 experienced multiple crashes which shattered all the solar cells, until [Daniel] discovered that the wing flexed under aileron input. It also did not have any form of solar charge control. V2 added a second wing spar to a slightly longer 9.83 ft / 3 m wing, which allowed for more solar cells.

Solar Plane V3 was upgraded to use a single hexagonal spar to save weight while still keeping stiff, and the solar cells were more durable and efficient. [Daniel] did a lot of testing to find an optimal solar charging set-up and found that using the solar array to charge the batteries directly in a well-balanced system actually works equally well or better than an MPPT charge controller.

V4 is a departure from the complicated carbon fibre design, and uses a simple foam board flying wing with a stepped KF airfoil instead. The craft is much smaller with only a 6 ft / 1.83 m wingspan. It performed exceptionally well, keeping the battery fully charged during the entire flight, which unfortunately ended in a crash after adjusting the autopilot. [Daniel] suspects the main reasons for the improved performance are higher quality solar panels and the fact that there is no longer film covering the cells.

We look forward to seeing where this project goes! Check out Solar Plane V4 after the break.

We’ve covered some of [Daniel]’s other projects before including GPS guided tupperware, a flying stick and a retina searing spotlight. We’ve also covered another solar flying wing.

19 thoughts on “Soaring With The Sun: 4 Years Of Solar RC Planes

    1. What I would love is a drone that just follows my car at a decent height and keeps track of other cars around me so that I can overtake in otherwise unsafe places.

    2. I’m more thinking of the possibilities of ultra long duration flights, if it is possible to make this vertical takeoff(Which i have my doubts about).
      If this is GSM/3G/4G-enabled i can basically fly wherever i want, and when the sun goes down, i land somewhere where it will be left alone for the night(Thinking the roof of some big industrial building or out of sight in a big field) and the next morning, when the sun goes up i can take off and continue my journey. I realize the risks of rain or the wind making it impossible to fly for maybe several days, but i’m not planning to go several hundred km away, “just” like 100 km, where i can go get it in an hour or 2, should it crash or have some other problems.

      1. A fun idea – with a little more power a plane like this could probably become a VTOL tail sitter – need more powerful motor/prop combo as I don’t think this set up would be able to go vertical (want more power storage as lifting entirely on the prop is going to require a huge amount of current and you don’t want to run out of power. Obviously landing those has never proven easy, need a good power store to let you hover and come down very controlled unless you want to try the suicide burn approach and full throttle go vertical right before you stall and smash into the ground using up your last few amps.

        I think for myself I’d try using two folding props and small motors for the differential thrust if taking that vtol approach. Which wouldn’t add much unnecessary weight or drag for a tail sitter as you are going to need stabilizers to land on. Which can then house much of the electronics and mount the motors. So you loose most of the fuselage hopefully even all of it – though getting the cg right probably means a longer nose full of battery. IF the wings are shaped with dihedral tips and at the kink there is a landing support/rudder pointing down it might work without the tail sitting rudders occluding the solar panels much.

      2. You can actually shape a craft to land back first.
        you need to slow the craft and bring her in.
        so you need at least 2 motors and you need to be a bit back heavy.
        Not sure how this will pan out but is worth a look.

      1. Hi Danie,

        I watch the wiring of solar cells in your video.
        I recall one sided wiring solar cells have been on a market some years ago.
        Since I build solar wheelchair, placing solar panel on a light trailer I would like to learn morre about the state of the art in one-sided wiring solar cells.

        Let me know more details

        thank you

        darius

  1. Hacking r/c aircraft and aerodynamics is just as much fun and technically in depth a hobby as the electronics, but has the electronics beaten in one very critical way. You get to take the family out to the flying field lots to enjoy the outdoors and a picnic for the day, or even out to the lake to fly off the water. They loved it. Plus battery powered flight has reduced the effort needed for outings from a large field box and at least a gallon of fuel to just battery charging. The batteries have improved so much these past 20 yrs that it IS worthwhile to take a shot at it.

    To get started there is no point to just looking at advertisements to pick equipment. Find a club, they’ll get you pointed in the right direction and typically will provide the first aircraft selections and flying lessons. Once your thumbs know how to handle the transmitter you’re good to go! Takes a couple weeks just like beginning electronics classes do.

  2. Could be interesting to make a VTOL version. Then you can fly it around the world on mobile internet for telemetry. When it runs low, u can just land it somewhere for a recharge :)

  3. Great project!

    There’s a lot of energy being lost in those silicon photovoltaics, though. Gluing them to a piece of foam greatly increases their operating temperature, which greatly decreases their power output. Once he gets some of his basic problems worked out, he’ll start wondering why those cells are underperforming.

    It’s a good problem to have :-)

  4. Great project by: Elliot Williams

    https://hackaday.com/2016/05/10/solar-fpv-plane-flies-forever/

    https://hackaday.com/author/hexagon5un/

    I watched the video published in 2019
    https://hackaday.com/2019/10/09/soaring-with-the-sun-4-years-of-solar-rc-planes/
    and would like to learn more about the wiring of solar cells.
    Wiring on the video looks backside only.
    Do you use special, one sided wiring solar cells ?

    I would like to learn more since I build solar wheelchair and plan to put light solar panel on a light trailer.

    Glass based solar panels are heavy for testing and can break easily
    So called semi-flexible solar panels are more expensive and may not match the size of a trailer or 24V input voltage (2 x 12V gel batteries)

    So give me a hint on solar cells used and wired so promptly.

    thank you
    darius

    manta103g@gmail.com

      1. thank you for your reply

        solar cell tape works for two-side wired solar cells only

        in case of back contact or one sided wired solar cells, you need to use BUSBAR Dogbone Copper tabbing strip
        https://www.ebay.co.uk/itm/BUSBAR-Dogbone-Copper-tabbing-strip-for-Maxeon-Sunpower-solar-cell-5×5/283193306578?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D40733%26meid%3D1ee82017c20643bcb4ff9d8f7df820cd%26pid%3D100005%26rk%3D4%26rkt%3D12%26mehot%3Dpf%26sd%3D133117267567%26itm%3D283193306578%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100005.m1851

        more images of dogbone and one-side wired/ back wired solar cells

        https://www.bing.com/images/search?q=BUSBAR+Dogbone&form=HDRSC2&first=1&cw=1129&ch=622

        back contact solar cell was great innovation, promoted 5 years ago on the Internet but never succeeded due to pricing policy

        I have contacted 4 manufacturers of solar panels in Europe to let me buy raw solar cell strings (not laminated) to let me build solar panels on my own.

        Unfortunately the businesses collapsed due to price wars and back contact solar cell is back an option for me.

        Ok, I can buy overpriced semi-flexible, non-glass laminated solar panels for use in solar wheelchair, but there is no option to buy such solar panels cut to fit the size and shape

        Building solar cars is all about it, how to stick and interconnect tens of solar cells to roof frame of car body.

        BTW
        hackaday.com fails to notify me of new comments via email or to notify me of new posts via email.

        my email
        manta103g@gmail.com

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