Instability: The Future of Drones?

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Let me know what you think of the videography and editing by Chris Edghill, I think I found my new secret weapon!

[@bowdlerise]

Getting my drone stuck in a tree isn’t the worst thing that happened to me today. But it’s definitely up there.

[@Inertia888]

Yes. It's definitely up there. 😂 For me, the worst thing, is I can't figure out which tree it's stuck in…

[@Videolinquency]

Just hang in there ...

[@adamhale6672]

Those side by side shots of quantum flying the same routes as serenity were amazing. It’s amazing to see your builds get better, as well as the cinematography.

[@BuckeyeStormsProductions]

I love the combination of technical and philosophical in your videos. You're production value has increased significantly, too. Great work.

[@Dogburt_Junior]

Just wanted to note charger coloumb counters aren't an accurate way to measure discharge unless the flights happened with the same battery in the same day. Ardupilot should have logging of the current and the refresh cycle of the logging will give Ah, which can be summed for the total Ah used. Better yet logging voltage and current to find Wh would be even better as it's not battery config dependent.

[@omotolaoyeniyi631]

The variation will not be significant in a statistical analysis

Also doing a balance charge makes it inaccurate because some of the power put in was bleeding off to balance the cells. You need to do a unbalanced charge to see exactly how much goes back into the cell.

[@uninteressant2196]

@@omotolaoyeniyi631 measuring both flights once is no sound statistical analysis

[@cben86]

@@uninteressant2196was also wondering how changes in air temperature (amongst other variables) between the two flights could alter efficiency.

[@abcdefg4570]

@@cben86 Wind is probably the most significant variable

[@Videolinquency]

Stumbling across your channel during an RC video surf felt like encountering a TED talk in a chicken coop. Thank you for restoring our faith in mankind.

[@marcusgardner9300]

Awesome! A word to all the "critics" commenting on here. I think the thing to remember is that he is documenting a journey of learning and invention. This is a snap shot of the process. You can't ever know what an idea is going to yield untill you start playing with it. Obviously this is not a refined highly technical break down. It's a step in the process of trying to see the viablity of his idea. If he waited until he arrived at the end to do a video we would miss out on all the good stuff in the middle and we wouldn't get nearly as many fun videos to enjoy. Great video and love the channel.

[@REALfreaky]

I love these efficiency tests! One thing, though: you should use watt-hours as your unit of comparison. mAh doesn't take the battery pack voltage into account. I suppose it's still valid if you're using the exact same battery pack between tests and planes, though.

[@thinkflight]

I assumed it was understood this was the same battery. I should assume less. Learning the right balance of under/over sharing!

[@Louis-ok3ry]

or joules

[@tim1234]

Your positive attitude, ability to cope with set backs is very inspiring! I designed, built and flew a flying wing as a university project and inherent stability is tricky with them. You showing us the capabilities of Arduplane and your building and designing skills is really awesome! Looking forward to your next video!

[@motionsic]

Great subject and goal of achieving longest battery powered flight. Love how you tied aerodynamics in with product placement for comedic effect. Tight edit with no wasted time. Respect!

[@bloodyfluffybunny7411]

i agree but now make it solar for sustained flight :)

[@scoutworks]

I think you can break the Titan Dynamics record for endurance with their Falcon V2. They claim 300.4km and 05hr:07m:30s in a single flight with a roughly 2.1m wingspan model. You've got this - you certainly have the brain and the drive for it!

[@ceradinimp]

Folding props with breaks set in ESCs. Props will fold up on power off. This should cure the motor popping issue. Amazing job on the plane and ardupilot. Learned a lot from your video. Hope to have my own Arduplane in the air soon.

[@nikolaihedler8883]

Pusher folding props can work, but require some modification to prevent the props folding past the center line and becoming unbalanced.

[@thinkflight]

Can't find counter rotating folding prop yokes though.

[@jtjames79]

​​@@thinkflight Ducts? Or wire skid style "landing gear". You could use a little servo to make the gear pop out. If you really want to be clever you could use some memory wire "skids" that fold themselves up and down with an almost negligible weight penalty. If you want to go for the record though I would suggest active flow control. I guess the easiest way would be to vector the motors. Now that I'm thinking about it if somebody could figure out a way to make props like itty bitty helicopter blades you wouldn't have to vector them. They would vector themselves by changing blade pitch. One last random thought. Ceramic based superhydrophobic spray, the reason it works is because it's THAT SMOOTH. Just saying. Good luck, rooting for you.

[@jaremarandall4386]

@@thinkflight Aeronaut makes both CW and CCW folding prop. And those one of the best props on market.

[@thinkflight]

@@jaremarandall4386 i did not know this. I will check them out again

[@calebcoburn2785]

Absolutely love this project. The humor in the video lands with me too. Well done and good luck! Can’t wait to see what results you are able to get. Thanks for sharing!

[@josephsworkshop75]

I always love seeing your videos pop up. Well done! Congrats. I look forward to seeing what this project develops in to. 👍🏻

[@LostMyName15]

Hmm. Much to think about. I have been trying to build a more efficient tilt rotor VTOL for a while now, but the main issue I had was the difference in optimal CG between both configurations. The wing needed a very high ratio airfoil to be able to stay stable during the transition, which killed fixed wing efficiency. Pushing the CG further to add stability was detrimental to the performance and efficiency in hover. Having the CG at or near neutral point would already be a massive improvement. I am definitely going to try out a split elevon design too. Keep on the great content!

[@mithrandir1313]

I would expect a drag reduction from the reduced wetted area... also, can you compare/contrast the efficiency of 2 v. 4 electric motors?

[@JohnDoe-fk6id]

agreed, as the boundary layer ingestion of the inner motors, combined with the tip vortex reduction of the outers, could significantly affect the results

[@thinkflight]

You guys see where this is headed....

[@KlingbergWingMkII]

Comparing apples and oranges makes any results suspect. Flow over the wing is different due to the additiona motors. This is a very difficult test to complete with accuracy without a wind tunnel.

[@portmanteau.]

I mean comparing 2 data points isn't statistically significant either. Add in were not taken on the same day, it's essentially garbage data.

[@Yeet42069]

@@portmanteau. Eh, its garbage data because the testing pool isn't sufficient yet. Even in variable circumstances you can get accurate data reflecting a generalization, I wouldn't count it out simply because its not tested in a wind tunnel, but further testing is definitely necessary to draw a better conclusion.

[@dfgaJK]

To save the motors you could connect the lower control surfaces' servos to a cam to deploy and retract (via spring) some landing gear / skids by moving the servo beyond it's control range. The control surface would then also act as an air brake upon deployment.

[@VinceSamios]

Man, ive been subbed for a long long time, and on the one hand im surprised youve only got almost 100k subs, but on the other, im super excited for you hitting that milestone and confident youll be at a million in 2 years. Amazing content, even more amazing quality of work. Mad respect.

[@thinkflight]

I appreciate that!

[@ScalarYoutube]

I feel like a cool project would be to invent some kind of contraption/landing zone that can safely bring aircraft to a stop, to prevent them from being damaged when trying to land. Maybe some kind of big and loose netting? Or if you want to go really crazy, some kind of autonomous car that matches it's speed and position to the aircraft it's going to catch, acting as landing gear.

[@boopidy696]

Is it just me or does this video seem higher quality than the previous uploads? New editor? I really liked the editing and production quality in this one, it was awesome!

[@taylorschoppe9656]

I love that he names his airplanes, serenity, and quantum, and I'm over here naming mine Dave.

[@thinkflight]

The project in my queue I am most excited about happens to be named Dave....

[@taylorschoppe9656]

@thinkflight Yoooooooo, I love the quality of your vids btw keep it up!

[@NicholasRehm]

Dang this looks eerily similar to something I’m cooking up! How much more efficiency you recon you could squeeze out with no sweep?

[@thinkflight]

I just dont think I'd have enough rudder authority with power off coming in for landing without the sweep. Otherwise, no sweep for the win. Someome should do that....

[@nikolaihedler8883]

@@thinkflight have you looked into Horten/Prandtl wing designs? They use something akin to extreme washout (negative wingtip angle of incidence) to gain some "free" lift and thrust by "surfing" the wing vortices, which are generated at around 70% of span instead of at the wingtips. These wings exhibit proverse yaw (i.e. positive yaw-roll coupling or self-coordinating turns) as a result, in addition to efficiency benefits in level flight. "Bell-shaped lift distribution" is another term characterizing this design concept. At larger scales, the design also generates more lift for a given mass, as the net bending loads on the wing are lower than a conventional wing generating the same amount of lift.

[@ConradBrander]

Yes, the Prandtl work that Al Bowers has done with his team is very much in this realm. You can get an 11% drag reduction for a 22% increase in the wingspan, and the plane will fly beautifully. Love your work Kevin, always a joy to watch. Please keep it up. ♥️🙏🏼

[@jcims]

I'm on the first letter of the first sentence of the first page of my journey to building a 100% solar powered UAV. It has been done quite a few times already but advances like this create usable margin where there was previously almost none. Congrats!!!

[@stuartwood7252]

Saw your latest TF come up this morning. I'm supposed to be moving house. Once again you've delivered. A Well worth distraction. Such interesting content, brilliantly presented. I might try shaving my head for the house move, to increase efficiency 👍 Stu. Melbourne.

[@user-zg2kr6ph9z]

can we talk about the manscape ad? it was brilliant!

[@marcjohnson4884]

I love this! I'm doing the same thing at my job flying a Caravan working to increase fuel efficiency and decrease emissions. By carefully straightening out every ATC route to the max, monitoring winds at altitudes available, and experimenting with torque and power, I am also gaining efficiency improvements in the ball park of 5-10%. Small victory for climate change. Your stuff is awesome, you should be at NASA, Airbus, or Boeing. Help build Sugar Volt so we can keep flying, traveling places, and improving the future.

[@flying0graysons]

Love these videos. The processes you go through of testing and evaluating. Plus beautiful flight visuals.👏👏

[@alttabby3633]

Great work man! I love your build process, methodology, and dedication.

[@paulogden7417]

Flight is magic! And so is this channel. Bringing together scientific curiosity, building know how and perseverance is engineering magic.

[@enriquetabora4399]

Just a thought. I used to own an old flying wing (can't remeber the name) that had the battery tray on a rail with a servo that could move it forward or back no more than a quarter of an inch. The instruciton manual said to takeoff at the nose-heavy end of the spectrum and to adjust in flight depending on desired flight speed (more speed, more aft). I destroyed the plane years ago so I don't have a picture.

[@ilikemorestuff]

Other hobbyists: These ailerons are going to allow me to do some cool stuff! ThinkFlight: I'll never use them, but the autopilot might like these split ailerons *sigh*

[@ZED-PV]

I nearly died at 11:44 🤣🤣🤣🤣🤣 Thats the reality.... your video editor did a wonderful job!

[@oadka]

At 4:34 I was quite surprised to see you hold the plane so casually with props on

[@bowmanzz1]

amazing. you test the stuff I always wanted to with some of my rc planes. really cool seeing someone else do those "what if" tests out there. keep it up. real great content here

[@Aengus42]

Absolutely fascinating! I'm just about to teach myself RC flying, ridge / slope soaring & the electronics that goes with it. I'll be using a 1500mm wingspan powered glider with a stabilisation system called Reflex V2. Final assembly is tonight plus I'm waiting on a couple of LiPo cells to arrive. I got the aircraft seven years ago just after I woke up with no feet after surviving sepsis. I needed something to aim for, something to get me out of that bed. I'd seen in hospital how people can just give up and lay there convinced their lives were over in their 40s. So I'll be following this with fascination & interest. Especially the technology, AI, sensors, RF & telemetry. And solar & storage if it t crops up. Thanks mate! Much appreciated! 😎☮️

[@thinkflight]

You got this!!!

[@Aengus42]

@@thinkflight Cheers mate! Lipos by just plopped onto the doormat this afternoon 😎🤞

[@deruhu9163]

That was interesting Although I'm not that experienced with building and flying rc planes (more a drone guy) know quite a bit about batteries and especially for super long flights I'd recommend 21700 cells especially the new LG INR-21700-M58T which has outstanding energy density 280wh/kg (21wh/cell). But they have a quite low power output at just 36w continues per cell. The Samsung INR-21700 50s would also be a Good coice but they have "just" 18 wh per cell but can put out way more power around 35A or 126w. I actually just got them today but have a jet to test them. I also thought about a dual battery system with a lipo providing the necessary takeoff power and the Li ion for cruising. You could also drop empty batteries once they are empty but you might consider this cheating :) Hyped for the next video keep it up 👍

[@thinkflight]

Was using 21700 Molicels for this.

[@AerialWaviator]

Quantium is fitting name for a craft intended to push the limits of energy efficiency. Your story telling game has taken flight too. Looking forward to seeing more on how Quantium is improving over its sister, Serenity. Noticed that both motors on each wing are spinning the same direction. Wondering if by reversing rotation direction of inner motors, Quantium may be able to use motor torque to help produce and control roll moments. This should reduce the amount of split elevon usage, thus gaining some efficiency. Same concept a quadcopter uses to produce/control yaw. Maybe this already an idea on a list for possible future experiments.

[@benjaminmiller3620]

But you'd be spinning one prop faster than another, while their forward airspeed is the same; _creating_ drag. My intuition tells me: more than the elevon usage creates, but I guess it's worth testing anyway.

[@bender9205]

This was honestly one of the coolest videos i have ever seen. It was just absolutely stunning. I went from interested to invested watching your jouney through this. Inspiring!

[@rohansully584]

Absolute pleasure to watch. Thank you for taking us on an exciting journey!!

[@abondutta]

what kind of job you do? the amount of research you do on your drone, and you earn for your family . your energy amazes me.

[@JeremySeitz]

great editing and filmmaking on this one! VO and music cues were great too! Props to the crew!

[@aaindtharivalan8720]

I too like to experiment until I find why or why not, this way or why not the other way.. We can definitely learn a lot from Trials and errors and practical experiments. We just have to keep it up and never quit. Another great video, thanks! 😊

[@hahaha9076]

Very cool life you're living. All the good ideas came from guys just like you. Great channel. 👍

[@wuzihuzi]

Yes nice one Kevin! This is such a cool project. Also great editing by Chris. The music was great, would love to know the artist/song at the end.

[@tonysu8860]

Very cool. Pushing the boundaries of design.

[@someguydino6770]

Perhaps add another servo to control the position of the battery and/or ballast weights mounted on a linear track that is positioned on the CG for takeoff and landing; but can be incrementally adjusted as they say "On the fly"? RE: task timing; get DEEPER workbenches with shelves above them ( might also wanna try some Lemon Fresh Pledge furniture polish on your head to further reduce parasitic "stubble" drag!) Gotta give props to the Crestline Soaring Society for using their landing area. Last thing; have you tested the difference in your acceleration quotient while leaving the bathroom after "Manscaping" your scrotum?

[@NiclasHorn]

btw, you could make the backend of the fuze more sleek and a few iches longer, to save on the drag.

[@WindCatcherRC]

I love how you used the EPP to make another amazing plane! Congratulations on the success of Quantum. Looking forward to your next video on this.

[@dbkgravity]

I had also dealt with this at one time. My personal goal was to fly autonomously for 90 minutes. The basis was an E-Flite Optera. Almost nothing is original on this thing. Motor exchanged less KV. Propeller less pitch. 4S Lion. Pito tube. The plane is super quiet when it is in the air and the altitude only old must. only 3.5A current draw. The thing is equipped with a raspberry Pi and large external WIFI modules for digital HD streaming (at the time there was not yet the DJI O3 module). I had to weigh what the bomber weighs, but you can't just throw it off the wrist. the center of gravity is so far back you can really see the wing surfing on the head wind the pito tube would be indispensable with me. without it it came again and again in curves to stalls. interesserweise the FLiegt does not fall enfach from heaven but screws itself then like a maple leaf down. Nothing ever gets broken.

[@curtisfoster540]

I connected with sooo much in this video, right down to the caterpillar omen lol. Definitely not easy building a groundbreaking flying craft, I know from personal experience. I'm pulling for you, all in! Congrats!

[@ChristieNel]

Stunning production. It's wonderful that you have a specific goal in mind with this.

[@steamnstuff]

@ 3:03: what software is this?

[@user-ry7ry5zb1m]

I don't know why it's hidden in all videos on this channel, but looks like XFLR5.

[@bikeislife8405]

Hooooolyyyy underrated channel!! Wow, your production quality is insane 🙌🏼

[@Johnellenberger1]

Very smart! Nice plane! You definetely have the right airframe to beat the record...

[@coderentity2079]

As a complete noob: pitch the two outer motors slightly up, two slightly down and get rid of all elevons. Make a solid state flyer ;) The other choice is to 'elevate' two of the motors, but that's more problematic.

[@nickl9461]

Kinda defeats the purpose of building an efficiency plane, to point the motor thrusts off the angle of attack. But efficiency aside, this is an intriguing idea on its own.

[@thinkflight]

How do you control the plane when you are power off coming in to land?

[@coderentity2079]

@@thinkflight Landing on the belly is a bad concept anyway - you carry no people - free your mind! Motor mounts break, props dig in - disaster. Do a last minute pitch up, lose all airspeed, turn nose down, do full reverse on the props, hover down onto the nose. An upside-down belly-flop manuver if you will. Even if it wont work, it's spectacular. But ofc for a few seconds you need TWR>>1.

[@Ozbird-72]

Love the way you run your content and channel... Those are "full watch" videos! Keep it up!

[@BooBaddyBig]

Fun fact apparently fossils of birds started off with long tails and then evolved shorter ones and bigger balance organs. I think it was assumed it was mainly a maneuverability thing to avoid predators, but efficiency works too.

[@gur262]

Now i imagine an incredibly braindead bird that looks alot like the easiest to fly airplane. The koala of the air.

[@gogglesfpv7986]

9:28 Whoah! that tiny fpv wing in the corner! i need to build one! could you do a video about that tiny thing? it looks like super fun to fly! this is a super cool project. would be cool to see you catch a record for longest battery flight!

[@RandomSwede-1]

This was a really interesting watch! I tried to build an unstable aircraft with an arduino to make it artificial stability back in high-school, but I lacked enough knowledge to get it it to work properly. Good job!

[@NiclasHorn]

i love flying wing´s / ( delta wings ). i have made MANY wings in my hobby day´s, most of them in balsa, and cover to make the wings low weight, much lower than you can make a floppy foam plane. but they brakes more easy at landing compared to reinforced foam wings. also my fastest ones is balsa wings. the looks have not been the best, but they fly good and FAST. and ofc, the wings have been symmetric or semi-symmetric. the slow loiter wings had have more of a glider wing profile to be slippery in the air. being up in the air for an hour is easy done with a wing that has a slippery glider profile. and i also made a mod for iNAV that triggers the throttle depending on what airspeed the peto tube reads. then the motors dont need to run all the time, and you never go down to stall speed. not even then flying with the wind (if the motor setup is powerfull enought) much of this thanks to @rctestflight #rctestflight then it comes to tinkering with iNAV. my next project will be a Horton EDF flying wing. in foam and fiberglass.

[@d9720267]

The dedication is inspirational!

[@bjlbernal]

Wow. Some really good documentary level editing.

[@primeum]

Just beautiful...Now we need a formation flight of both quantum and serenity flying through the same waypoint mission

[@alem84]

This is hands down the most interesting RC flying channel, thanks for the awesome content!

[@bobirving6052]

Thanks a lot for the video. Great production! I had been very eager for a follow-up on the aft cog, unstable wing design!

[@mhermenault]

My favorite video of yours yet, could really feel the magic in this one!

[@blezalex]

What servos are you using in this project? I think you can benefit a lot from fast (as fast as you can find) servos so flight controller has enough time to compensate for instability. Slow servo in the control loop ruins the whole things. Many servos can run higher voltages and produce higher reaction time when run on HV. Also I'd recommend actually testing the claimed reaction speeds, they differ a lot!

[@chemistt]

Maybe a silly question, and I have to say the throws at 7:33 are the ones of a master thrower....hat down....but why not throw overhead? I also sometimes throw wings from the belly but overhead seems less problematic...mainly in the evening when there could be moisture on the wing

[@willembont4790]

Well done; exciting times ahead. Thanks for sharing.

[@typxxilps]

looks really beautifull and well crafted

[@i_piss_rocks]

thats so cool, i hope in my lifetime we'll see blended wings like this take over the air cargo market. that would be awesome

[@1991jub]

Brilliant channel. Your videos keep getting better and better. Thank you!

[@SwordFighterPKN]

Can you try this with a swept forward wing design?

[@condor4679123]

How did you account for environmental effects on performance between the tests?

[@megatesla]

From the video he it seems like he only did one test. So he probably didn't compensate for any of the many variables....

[@thinkflight]

In this case the humidity was higher, making the performance worse than previous tests.

[@thinkflight]

Its not a wind tunnel. Real world tests only matter with big differences in performance.

[@v1-vr-rotatev2-vy_vx31]

We had stable radio-controlled flying wings back in the late 60s that we built from balsa wood.

[@Fuso4x4]

Outstanding editing and filming. Keep pushing boundaries.

[@tijssens]

The cpu running adrupilot = quantumcomputer

[@mikebergman1817]

This is the kind of video that people at the FAA need to watch. This is the kind of skill that will suffer under regulation of the hobby. Maybe they are cool with other countries bypassing us in everything related to flight.🤷‍♂

[@BABALOOEY46]

Such good work, love watching

[@Kabab]

Amazing work! In the next video, please explain more about where all the instabilities are. CG, low/no reflex and what else? Would a high wing aspect ratio with short/no fuselage apply? You implied as much with in this video, just wanted to confirm. I have dreams of a straight wing with no fuselage or sweep that can fly extra slow and efficient....

[@komandir_dfaa]

your content is inspiring!! I can't wait what contributions these results will turn into, I wish your luck on your journey

[@daxdadog]

Great video. You're getting better, and better at story telling!

[@appa609]

the highest cruise efficiency is almost always achieved near a static pitch margin of 0. Maybe A teeny bit of static pitch instability helps but not a lot.

[@IntelligentQuads]

Great project! Can't wait to see the next iteration!

[@kieren7763]

Lets just appreciate how well it launches for a wing that size

[@Vicybear]

however some aircrafts are using almost the same way to save fuel when they are making a long cruise. Such as Airbus330, it has a fuel tank inside the elevater, connect to the wing tank. The computer transfer the fuel from the elevater automatically to change the CG, reduse the drag from elevater which used to level the airplane on cruise flight.

[@Mike-oz4cv]

Afaik the CoG is still in front of center of lift and the tail still creates a downwards force in level flight (negative lift). It’s just smaller.

[@Vicybear]

@@Mike-oz4cv yep，they will never make it unstable. in A350, they think that system cost too much weight. so they extend the flaps a little bit to change position of COL. interesting

[@pascalfust1035]

I really appreciate your idea of challenging "aerodynamic facts" by experiment. UAVs give such a great opportunity to try out new ideas and verify in reality. I thought that blended wing designs might be most aerodynamically efficient, as such I am currently building one to verify. What's your thought about it?

[@dmitrynuzhdin]

Since you are doing an efficiency test I wonder how the motor power is optimized for efficiency? How did you optimize for the most efficient speed that gives the lowest mAh/km? Is it a feature of Ardupilot?

[@johnroyal4913]

I wonder if a body shaped like the SR-71 would make it efficient. Wouldnt be as stable but you have that figured out. Always enjoy these. Looks amazing.

[@Egg-mr7np]

This is good documentary film making, camera and edit.

[@shaunthomas9814]

Hey, just need a little help Can you tell what's the process of making the body of the plane? Not the 3D modelling part just the foam cutting part and the final layer part. I was planning on using it for a project of mine

[@nitzeli]

Hands down some of the best content on youtube. Thank you!

[@vericksworkshop5007]

Half way through the video but i would love to see a video going really indepth on your process of designing a plane like this such as picking airfoils, calculations and stuff. Like this if you would like to see that tooooo.

[@darrinbunston5932]

I'm not an expert but I would recommend prop savers There a hub with two screws sticking out that have an o-ring that hold the prop on

[@dfgdfg_]

Editing off the hook 🔥

[@Whitepalace24]

You test at Andy Jackson Airpark?!! That’s where I paraglide ❤

[@user-xt2di7bx7p]

Look's very good,how you set that spoiler RUD/flywing AIL ELV mix with ardupilot? I can set it in my Radio without CF.

[@silentblackhole]

When testing the efficiency difference/change how do you account for the wind?

[@chrissugg968]

The new higher aspect ratio wing shape looks way better too.

[@billytuchscher]

Such a fun video to watch!