RC Solar Plane Flight Duration Test 

Working as an engineer in a experimental solar technology department in Vilnius (Lithuania). I have full access to excess amounts of bifacial monocrystalline cells (152x152mm at 23%efficiency), regular polycrystalline cells (152x152mm at 16%efficiency) as well as solar film. It's efficiency is low at just 12%, but it barely weights anything, is sturdy to mechanical forces and is flexible (you can cover all the surfaces with it). Solar film is something me and my team are working hard on right now, I'd be happy to offer you all the extra we're expeced to have soon during launch of mass production. Have a great day!

home surveilance drone, each morning at 9am have it autonomously shoot out and circle your house with a continuously streaming camera feed all day, until night where it lands and waits for morning

As an aerospace engineer, most of what you said is actually pretty accurate. Reducing your aspect ratio will lead to more induced drag contributing to your drag coefficient, and as you go faster, "skin friction" drag increases with the square of velocity. At low speeds, the induced drag matters a lot because you need a relatively high angle of attack to maintain sufficient lift. As you speed up, your induced drag still exists, but the skin friction drag matters more because it is related to the square of velocity (a third component you did not mention was pressure drag, which also increases with the square of velocity, but since you have a pretty small cross-sectional area going into the wind, it should only be a small component of the drag). I think if you added some winglets, you could bring the induced drag you have down considerably and get a much more efficient plane. But sill, a very cool plane anyways. I'd love to see what else you make.

So proud to see young folks with these amazing projects. The future is in good hands!

14:40 "You'll probably need to be streaming in HD" Me: How dare you underestimate my neighbor's wifi.

Le* Author " I am no aerospace engineer" 5 mins later.... Discussing plots of every type of drag and AR for wing and structural airframe trade-offs. Classic rctestflight

"This is very dangerous" @ Kicks swollen battery yelling "blow up already"

Each time I watch your videos, I remember when I was a young teen in the late 90's early 2000's, I was practicing RC planes piloting as a hobby (I should say as a religion lol). With my friends we were tinkering and building amateur RC planes with scrap and propelled them with small 2-strokes engines, sometimes RC engines, sometimes stolen from strimmers or little chain saws XD. There were no GPS modules, nor there was any sort of gyro stab or even more any fps cam, wifi, or whatever. Flying a RC plane truly was a pain in the butt in those times. Amazing to see how far we've come from this era, with all the auto pilots, auto-stabilized drones, electronics modules, electric engines and all. This always amazes me.

You need to do a long range flight with one of those !!!!!!

In the footage from directly above the field you can not only see the solar plane, but also the solar rover and the figure 8 it made in the grass. :D

rctestflight : "I'll be glad if I never have to fly a plane for 9 hours straight ever again, it's not a great use of your time." MS Flight Simulator player : "I don't get it..."

Thanks Daniel. I really love being able to tag along and vicariously have these RC adventures (even though they're probably way more boring while you're filming them!)!

OMG a new solar plane video. YAAAY!!!!

Hey Daniel, you should take a look on an "Active Balancer Board". It's a little and lightweight PCB that you can attach to a battery pack and it'll balance the cells automatically and more efficiently than a regular BMS. The BMS burns the excess of energy from the cells while the active balancer transfers the excess to the other cells. Also, you should be careful with the BMS because it will actually CUT THE POWER OFF when you overcharge and overdischarge the battery, which is not good when the battery is required to fly. What you need is a switch to disconnect the solar panels manually in the case of MPPT charger is not doing it's job. Your project is great, keep it up! You can do an "infinite flyer" for sure. That's the next step.

What a compelling use case for solar power. Seeing it replenish its own power constantly while in the air was simply magical.

Thanks for the safe battery disposal tips

Those panels are a really nice shade of blue

Brb gonna charge my battery *flies plane *

Nice video dude, i've been highly impressed by such experiment of yours. Just recently planned to create and mount a solar powered water heating system for my summer shower (for any cloudy days), but for some reason i cannot engineer it. Those projects and channels like your seriously inspires people around the world such like me to learn a lot of new things. Good luck with this cute plane.

I used to work at a thin film solar company where our primary target market was aerospace applications. Happy to talk with you about the concepts and how things work on large scale aircraft too. Conversation efficiency and packing factor becomes a big deal in relation to the design space.

I'm not in the hobby but really love watching your videos for the iterative design and engineering involved. Thanks for making cool shit and putting it on the internet for the rest of us to enjoy!

"I'm glad I won't have to fly a plane 9 hours straight ever again. Not a great use of your time." *Flight simulator 2020 exists*

That is SOME KINDA AWSOME!!! Well done, and kudos on the patience and endurance...you AND the plane. I experiment with new solar stuff, also. I'd be interested in the new solar film, mentioned by the OEM in comments. Keep flyin' (and keep yer girders up ...engineering talk). All the best...great vid !!!

I have zero RC experience but I am fascinated by your solar and autopilot videos. It'd be really neat to see as a next step in a series like this to have a plane fly around all day and have a camera track you as you move around. The applications for this could be for something like hands-free aerial footage of you dirtbiking or even playing airsoft if you could get it to stream the video to an Ipad. Whatever you choose to do, I guarantee I'll continue to watch it bc I love your content!

Daniel, really like how you’ve done your homework here. Understanding that increasing the AR of a plane with constant weight, does not in all cases reduce induced drag is a key part of understand the total drag equation. I agree with your theory, although I would love to see the same aircraft (same weight and planform thus same wing-loading), with a larger span to see the increase in performance. I think you are on par with the average aerospace engineer. Good luck!

Genuinely my favorite project on RU-vid. Keep it up man, it's super interesting seeing the progress

thanks for the videos Daniel. Always enjoy your ideas and your thought process. So much information and easy to understand and follow.

I just found my new FAVORITE channel! Usually it takes several videos for me to say that but this was enough to hook me!

DUDE that super high birdseye shot was my favorite! such a cool perspective.

The biggest Problem with HAPS (High Altitude Pseude Satelite) is the fact, that they fly really high (~20km). So the air is really thin which affects the lift generation and propulsion, hence the need for multiple propellers. This means those planes operate at quite a high lift coefficent resulting in a lot of induced draig. The only way to lower this drag is to have a long slim wing. As they are as light as possible, these planes are really elastic and can only safely operate in these hights where there's almost no wheater. A few were ripped apparat during ascent when they hit some turbulence (NASA Hale and Zephyr). I do not agree around 6:06, you increase your induced drag dramatically because your aspect ratio is lower. Also i think the graph you showed only applies for one plane. If the same plane flies faster, it has to operate at a lower lift coefficient and thus decreases induced drag. But i come to the same conclusion. Your plane workes well because it flies during the day. There it is more important to have enough surface area to power the propulsion. It can thrust through the increased drag. But anyways, thanks for those cool videos. I love to watch them.

Love the solar plane serries, been following this progression for a while now.

Love the in-flight commercial.

The solar plane series is great, really enjoyed the sketches and explanations! :-)

Fun, engaging and super-interesting technical topic - as usual! 😁 Really appreciate sharing your *hours* in the field.

BTW, good videos, ty. I enjoy seeing how you work through problems based upon you initial question(s) and actual testing regarding RC’s. On the topic of AE design efficiency, ... if the outer layers of the wings were constructed of a translucent material enabling and aerodynamically efficient built-in-curve, then the airflow disruption by the solar cell structures problem is negated.

I keep watching this over and over. I love it

Uses for this technology keep popping into my head. A small, quiet drone with huge loiter times. Intelligent enough for it to fly a course without human input. Be it to reach a point & circle or fly point to point. Fascinating video.

The wing is very reminiscent of the B2 bomber wing... add a bit more span for more cells and lift...

yes, arduplane sets home position at arming location. if you want it somewhere else, you must tell it, or re-write the auto mission and select Yes to load set home coordinates

great video glad youre still working hard on this project

This is awesome! Ive been watching your channel since the OG days years ago!

Dude. Make a kit. Id buy it!

Great video as usual, I'm always looking forward to the next solar plane vid!

i like how many of these videos there are where the rover is just simply vibing

I've had your issue with the Genasun. They explained it quite complexly... It's more like this, the genasun is just a boost converter, which means when the battery is full, the mppt can still overcharge your battery is the voltage from your cells is higher than the battery voltage. It does not have an extra switch to enable overvoltage cutoff on the output. On Ali there is an mppt based on the lt8490, that is a feature-rich chippy with buckboost power stage, way more safe. Still get a bms though! :)

The video I've been waiting for ALL SUMMER

Nice work, over the years. Nicely done.

Wow, very cool--I'm interested in seeing what comes of it!

7:14 oh cool a 747 dreamlifter! Lucky

Fast to a new rctestflight vid nice!

for the wider thinner concept, you could make the wings foldable and detachable using keying or hinges. combine the panels using a branched quick connector . maybe also shield those wires around the compass or use already properly shielded wires that would cross that compass.

Very cool. Super impressive. Experiments like these lead to awesome future inventions.

5:20 depending on where the plane works and how fast it can travel, it could maintain itself in an area of the planet that has more sunlight hours per day, like stayint in northern hemisphere in summer then southern hemisphere in summer

Could you also mount solar panels on the bottom of the wings to capture any reflected light from the ground (clouds for higher flying planes)? It would be interesting to see the effects over various surfaces and at various heights.

I actually back spaced to like this video, love this kind of research, brilliant.

Great project, to my eye your wing is actually more of a delta wing which has a different aerodynamic characteristic relying on creating vortices to achieve lift rather than traditional wings where long slender is better as you mentioned

10:15 "The compass didn't seem to be working" Daniel, you know how it says "Bad Compass health" on the screen there? Yeah, it shouldn't be saying that while you're flying...😂😆 Really cool plane though. Impressive that it flies the entire day.

Next video, can I suggest removing the battery and doing a straight solar flight with no battery and flying purely on solar power only..... the excess power and fully charged battery shows that it can be done. Great video as always

id love to spend a day learning with someone like you this is an awesome video

Great video ! Since you're overcharging the battery you should test how high you can fly it by using the excess power to gain altitude !

Awesome aircraft. Being an Aerospace Engineer, I'd suggest a high aspect ratio wing but a straight wing configuration. Since this aircraft is travelling at low speeds, swept back won't generate as much lift as a straight wing would at same speeds. Also, swept back wings are generally used for aircraft that travel at higher speeds e.g passenger airliners. This is because at such speeds (mach 0.8), airflow over the wing surface easily accelerates to mach 1 (speed of sound) forming shockwaves. Therefore if you want to increase the efficiency of this aircraft model, go for a straight wing and if you really care about the induced drag throw in some winglets👍🏽

Race The Sun vibes... loving the concept!

Well done mate. You made a working 100% eco friendly day plane. 🥳

7:25 what the...

You should send it on a super-long long-distance waypoint mission next.

Thats mental !! I didnt even knew it was possible.

So I'm watching this video for like the third time after 2 years, and what you said at 7:00 just made me realize you make a great point. I should totally build one of these.

"Oh you just wait, past Daniel" hahahaha

We need a V5. All in!

Great job showing how possible this is

Love your videos keep up doing them! And this video was uploaded on my birthday

Can thermals be "generated" with a dark tarp, or some surface like dark pavement?

Next flight....9 hours in one direction following in the car!

Since you are dealing with radio frequency I would try to make all the wires inside as isolated from each other as possible, and also as symmetric as possible in reference to other wires. Your signal carrying wires should be placed far away from wires carrying power. You have to imagine that there are electromagnetic waves coming out of all of your electronics at the speed of light and they interact with each other no matter what. It's best to make it as pretty as possible. Imagine all those wires jiggling around inside that tiny plane. They wouldn't do that in a boeing jet. Spend the time making those wires organized! It will help! A++++, you're a genius.

Excellent work. I think you can have a high aspect ratio wing with a low complexity only if you fan fit sufficiently slim batteries along the wing to avoid concentrated mass. That way there won't be a central mass to be supported by the wing. This would probably be simpler on a larger model where you could have a thicker wing.

After a year of your every RC project its weight increase..... Because of hot glue😂😂

That lipo gave me anxiety

REALLY impressive! Good job!

Nice video shot, well done, thank you for sharing it with us :)

Could you build an "auto thermaling device" for sailplanes? I think this would be super awesome :D

Could be fun with mobile internet on-board, fly all day anywhere there's cell signal.

Went as we expected. Nice

I love the deep nerdery on this channel, making the science accessible. I wonder if there might be something to coating the non-control surfaces on the top surface of a plane with a photovoltaic film like ASCA makes might help tip the scales back in favor of more efficient airframes, so that such a drone can continue lingering into the night with only occasional thrust. Of course with the FAA mandated altitude limits for drones, that’s going to be a limiting factor in terms of getting above cloud cover and turbulence.

I was wondering if there are any auto-thermal estimating/route planning software. ie automated use of thermals?

loved the sponsor skits XD

I know we are all talking about the sponsor and airplane but the Boeing dream lifter on the video was really cool.

You know what?, I watched this whole video. I enjoyed it, thank you for sharing

Let it fly at/with the sun and see how far it can go

Dang... If only I could get flexible solar paneling (solar fabric?) for my paramotor... Could run the wires from the glider through the carabiners! One day.

Cool plane mate. Very nice.

THX for the wind protection. I love to see it :-) There is nothing more annoying as the wind messing up a whole video

Try some long range bombing runs on north Korea and launch from south Korea, just an idea🤷‍♂️

Really great video. I guess one lesson I got out of this is to have some sort of Voltage limiting circuit that will kick in case the charging circuit fails for some reason.. .Odd, that it failed to protect the battery... Thanks for the video.

Wow, Big thanks for this video! specially the 14:46 view, it'S insane. Keep your good work!

Perfect for a Farmer to monitor their fields from their mobile phone. Obviously only on good days but who knows as the system progresses it could offer night time security as well. Love it.

My expectations for where this will go in 2022: - Lighter, stiffer and stronger materials. - Improved fabrication process. - More efficient motors. - Better batteries, with reduced weight and higher capacity. - A smart Battery Management System. - 9-axis IMUs (compass, gyros and accelerometers).. - A dedicated altimeter separate from GPS - PID controllers. - Aerodynamic refinements to improve efficiency, stability and lift without sacrificing everything else. - Lighter and more efficient solar cells (and with a larger quantity of smaller cells that can fill the wing more completely). - A supercapacitor to assist the battery in initial launching, via the electric equivalent of a rocket-assisted take-off. Can also recharge quickly enough to provide the occasional boost when necessary. These expectations are based on budgets increasing thanks to a rise in popularity and blessings from the glorious algorithm. And also based on the technology being made available to hobbyists getting better. And based on improved knowledge and skills for developing things.

Nice shot of the dreamlifter!

Great work love your videos!

most enjoyable - thanks for sharing.

Thanks ! ! I enjoy learning from your productions. '73 Bob