One of the most frustrating parts about flying a quadcopter is having to regularly swap battery packs, as this massively limits what you can do with said quadcopter, never mind its effective range. Obviously, having the sun power said quadcopter during a nice sunny day would be a much better experience, but how workable is this really? While airplanes have used solar power to stay aloft practically indefinitely, a quadcopter needs significantly more power, so is it even possible? Recently, [Luke Maximo Bell] set out to give it a whirl.
His quadcopter build uses a large but very lightweight carbon fiber frame, with large 18″ propellers. This provides the required space and lift for the solar panel array, which uses 27 razor-thin panels in a 9×3 grid configuration supported by a lightweight support frame.
Due to the lightweight construction, the resulting quadcopter actually managed to fly using just the direct power from the panels. It should be noted however that it is an exceedingly fragile design, to the point that [Luke]’s cat broke a panel in the array when walking over it while it was lying upside-down on a table.
After this proof of concept, [Luke] intends to add more panels, as well as a battery to provide some buffer and autonomous flying hardware, with the goal of challenging the world record for the longest flying drone. For the rest of us, this might make for a pretty cool idea for a LoRaWAN mesh node or similar, where altitude and endurance would make for a great combo.
I’m impressed that this works at all. Makes me wonder what is possible in terms of solar powered airplanes – given that quad rotors are not particularly energy efficient things…
SPOILER: It doesn’t. There are li-pols hidden in those carbon fibre tubes.
Are you sure? The body of the quadcopter seems light enough to get by with the amount of power generated by the panels. I’m no expert and haven’t ran the numbers but it still seems within the realm of possibility.
I guess
If this was a random YouTube short, sure.
This guy has created a number of detailed projects on YouTube and nothing here looks beyond the realm of possibility.
This isn’t a small, inefficient quadcopter being powered by some heavy polycrystalline panels.
This is a big quad with large, efficient rotors carrying a very large, lightweight and efficient panel in full sunlight.
I’m surprised it works at this scale, but it’s believable.
Why would he bother with that?
He actually plans to stick to stick a lipo on this, it isn’t planned to be batteryless, this was a test flight before adding the batteries.
And if you watched the video it basically runs out of power momentarily and almost crashes after his maiden batteryless flight.
A 747-8s wingspan is 224 ft 5 in at the root they are 48.7 feet long tapering to 12.1 feet at the tips. That gives you roughly 6,824 sq ft of wing surface. Youve got ~250 feet of length in the fuselage with a width just over 20 feet. If you were to wrap it completely with solar panels, Ignoring the inefficiencies caused by indirect exposure this would cause, youd have around 15700 square feet of panels on the fuselage.
So in total a 747-8 could squeeze in around 22,500 square feet of panels. highly efficient solar panels can theoretically capture a maximum of approximately 472.5 kilowatts (kW) of power
The Boeing 747-8 has a maximum takeoff weight (MTOW) of approximately 987,000 to 990,000 pounds (447,700 to 449,056 kg). with estimated power consumption around 240 megawatts (MW) for takeoff and approximately 60 MW during high-altitude cruise.
472,5 kw of power is less than that produced by the engine of a 4729 pound Cesna 208.
So the potential of solar power for fixed wing aircraft is pretty poor unless youre talking about ultralight weight powered gliders and drones.
Not really, its certainly a more natural fit than rotational aerofoil lift of helicopter and multirotors. You just have to actually design to suit the methods you intend to use, a 747 is all about stuffing as much takeoff mass and volume as possible into a footprint that works at most international airports making use of the huge power density and performance of their fuel and engines. It is bulk transit efficiency around existing infrastructure that was considered not flight lift-drag/power requirement to surface area. Where something like an existing motorglider design or that really crazy looking Verhees delta would naturally work rather well (assuming you can make the structure work with the panels still) as already an efficient flier and has actually rather giant surface area for its size. But likely need to scale up a little from the very small lightweight aircraft they are…
If anything the ultralights are the hardest one to design as directly solar powered – you have no mass budget to speak of to start with. So even with the huge energy density and performance to weight ratios of aircraft engines they are not that easy to design. The Electric Motor might well be a touch lighter but having to pack in lots of mechanical supports for a wing surface material that isn’t really structural is probably making a functional solar ultralight on the verge of if not entirely impossible with current material science.
Uhh you wouldn’t just use direct solar energy for takeoff. Also you listed a weight for a plane full of fuel. What would actually be done is likely the following. 1 definitely not for heavy cargo applications, of course. 2. Batteries fully topped up on shore power to provide the necessary acceleration up to cruising altitude. The weight of the batteries offsets the weight saving from the fuel as well as the dry mass of the jet engines. Electric motors can be much smaller and lighter. 3. Really I think with current technology the best approach might be to use a smaller more efficient turbine to provide the power to the electric motors during take off. Ascent, as well as to provide any emergency power that might be needed, kind of like a turbo button. And finally 4. I think the article was actually talking about uav’s
O and on top of the things I mentioned above, you also didn’t account for the gain in efficiency from the elevation as well as the significant decrease in temperature. Some quick Google searching showed an installation at 1900 meters elevation that generated 50 percent more power than it would at sea level.
I imagine at plane cruising altitude it would be even better
You don’t need to power the whole plane. You could use a solar wing area to supplement the jets.
1kg of JetA1 =120MJ * 20%efficiency = 24MJ work
1kG of 3.5W, 6g , 200um flexible cells, *10hrs = 19MJ
That is standard thickness Si wafers. Given the active junction is a few um, they could be much thinner, and would then be able to produce more thrust than the same weight of kerosene.
There was an ex-russian company that peeled a um thin GaAs junction cell onto (kapton?) film. They claimed significantly greater energy than kerosene, as the cells were very, very light and higher efficiency than silicon.
A 747-8 burns approximately 2.67 kg to 3 kg of fuel per SECOND during cruising flight. The wing area could provide roughly 1/1000th of the power required during cruising flight under ideal circumstances.
POINTLESS.
IMHO, NASA’s Helios Flying Wing reincarnated as a copter on a shoestring budget. Add some aerodynamics and it will be Osprey on a budget.
what if they used “double-side” pv panels aligned vetrtically below the cruciform struts?
Random idea, use a weather balloon covered in solar panels, then hang a drone below it on an umbilical. Use the drone to tow it around or to keep it on station. — google say it already exists, https://en.reset.org/this-helium-powered-h-aero-drone-can-fly-for-24-hours/
Why on earth use a drone for a LoRaWAN node when a tethered balloon would work so much better and so much more reliably???
To not be where they are looking for you… don’t worry about that whole broadcasting as loud as possible.
Although it could be a limited use version, only used when necessary and kept up in the air waiting otherwise. Kinda cool.
I was out last week with a 250 gram toy quadcopter and struggling with trying to bring it back in what I had thought was a light breeze.
I expect this solar panel thing will flip over and fly better as a kite.
Brilliant! Why not use a kite as LORA wan node?
Is there practical lower weight limit for solar panel construction? my understanding is that the semiconductor making actual electricity is just few atoms thin and rest is there just as thickness to provide strength and prevent the crystal structure from cracking. or maybe accomodate quarter wavelength of the converted light, which is waaaaay shorter than thickness of panels available nowadays.
Im no expert, but i beleive that while we might be reaching practical limit to how much energy can panels make per square meter, there is still huge margin of how much energy can panels make per gram. just imagine mylar-like solar panels. maybe with graphene? that would be crazy light compared to what we have now.
Great project. Maybe combine it with a small helium balloon? Other than lift, the balloon could help support the fragile panels.
Looks like you could save alot of weight in the mounting hardware for the panels. The 3 sets of branching mounts seems inefficient. I might try just 3 horizontal bars that overlay the x of the drone. Maybe an additional support for the middle bar out to the edges of the x. Additionally I would put as much spacing in between the panels as I could to try and stop your drone from becoming a kite.