Un-Folding a Quadcopter to Increase Efficiency - Part 1
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- Опубліковано 12 тра 2024
- Thanks to PCBWay for sponsoring this video--check out their website for an instant quote on custom PCBs, 3D printing, or even CNC machined parts: www.pcbway.com/?from=Nicholas
If you take a large, efficient wing and fold it up into a box, you can turn it into a quadcopter. This sounds kind of silly, but I promise there’s some distinct benefits to controllability in hover, and efficiency in forward flight.
Patreon: / nicholasrehm
How a tailsitter transition works: • Taming the Tail-Sitter...
Can wingtip-mounted motors improve efficiency?: • Can Wingtip Motors Imp...
Peter’s mini quadrotor biplane: • Chasing the VTOL Tail-...
Tail-sitter VTOL designs are a hilariously simple approach to the challenges of mashing an airplane and a helicopter together. Just make a flying wing take off from its tail and pitch over 90 degrees into forward flight. But to improve the efficiency of forward flight generally means to degrade the controllability in hover, since increasing the size of your wing also increases the amount of surface area that can be blown around by the wind. For tailsitters, forward flight efficiency and hover controllability have always been in direct conflict. This design is my attempt at remedying this classic tradeoff, to see just how big of a wing we can turn into a tailsitter. Folding it up allows for motors to be placed in each corner like a quadcopter, dramatically improving control authority, while reducing the wind-facing surface area in hover. If you found this video interesting and want to follow along as we inch closer into forward flight, don’t forget to subscribe!
Intro: 00:00
Design Overview: 00:57
The Build: 03:25
First Flights: 05:15
Forward Flight Game Plan: 07:14
Transition Testing: 08:00
Conclusions: 09:56
#FoldWing #VTOL - Наука та технологія
That moving X-ray overlay of the 3d design at 2:22 🔥
Thanks for noticing 😃
Oh yeah
Real lit indeed
I had a little bit too much fun doing some video transitions: ua-cam.com/video/uxb8ACWtDkI/v-deo.htmlsi=BhoITlYh0DR6NczF&t=50 (similar project, btw.)
Next time, an X-ray overlay. Great idea.
Earned my sub instantly
The oscillations are due to the polyhedral on the wing. You're ending up in a Dutch roll situation. You might want to try unfolding further before pitching over for forward flight. Another option to consider is a Z shape instead of a U.
Yup, I concur. And all that mass at the wingtips wobbling around is probably making it worse. Still, damn impressive!
I'm thinking he needs to dampen yaw oscillations with a control loop using differential thrust from the tip motors. The lack of vertical tail and huge dihedral make this especially Dutch-rolly.
Might be that, combined with poorly tuned PID gains
i'm guessing it would be fine to crank the damping values up quite a bit since you don't need much agility during the transition
it's effectively like having huge dihedral right? so there's a strong bias towards rolling back to center
I'd love to see this design "fully unfolded"
Hopefully soon!
The geometry of the plane seems off. I think it would lack roll/rudder authority for such a thin wing without sweep.. unless the software is very good :p
* ba dum tss *
@@ethanhermseythat's why he designed his own flight computer
@@NicholasRehm
I wish you success.
So where is part two. Im wanring more
After 5 months I'm guessing this channel is dead 💀☠️
I can already imagine the full transition looking totally majestic! Really excited to see part 2, great work 👍💕
Thanks!!
Can't wait for part 2 this is quite possibly my favorite project of yours yet. Such an amazing awesome design
Guys like you here on UA-cam who are doing backyard/garage engineering give me great hope for the future. The things I see you do are amazing to me (a non engineer). I look forward to your next video and wish you great success in your future, but a guy as smart as you doesn't need luck.
I am also impressed with the comments on this video too. Lot of seemingly smart helpful people out there.
Wow. Good on you for being patient with the forward flight transition and taking the time to tune. Keep going!
Well done. I like hearing the details of 3d printing. I never heard of lightweight PLA before, good to know. Looking forward to episode 2.
This video is so well made and I love the design. Can’t wait for the next part!
Many thanks!
Fantastic! Love this one.
I've been redesigning some of my linear actuators and playing with load rating them a bit. I'm glad to see use of linear actuators in this sort of application. Very impressive use of torque and lever action over that long distance. I'm surprised (impressed) how your printed materials stood up to the forces they had to endure.
Great job!!
I have been thinking about this for years, bravo! I look forward to see how this further develops!
Mate, I have been a follower since the start, I fly professionally in the DCL racing league, me and the guys love how you've been furthering the hobby! Keep going!
That’s awesome, thanks!
This is a super cool project! Very excited to see the next video and hear how you smooth out the instability. Can this be done with SW only or will it take physical changes? CH change? A tail of some sort? Good luck!
I have become intensely interested in transitioning EVTOL. This platform holds so much promise to create the new age of aviation where you can take off from your yard and fly hundreds of miles on electric power.
Thanks!! It will definitely be a software fix, but there’s some hardware tricks we can play with to make that process a little easier. I’m thinking some removable horizontal tails to temporarily improve longitudinal stability. The end goal is actually an unstable wing in forward flight, since those can be even more efficient. Kavin @thinkflight has played with this idea quite a bit
@@NicholasRehm The whole concept of a VTOL, high aspect ratio, unstable wing is so appealing, it is the best of all worlds!
I don't fully understand the advantage of having the center motors off in forward flight, I would have expected distributing the thrust across more motors would be more efficient. I guess with a decrease in tip motor speed there is a decrease in tip vortices reduction so maybe that is the tradeoff? Maybe you can explain more in the next part?
@@dfgaJK A wing requires ~1/3 the energy of an aircraft hovering on thrust alone to carry the same weight. Turning off motors reduces power, and increases flight time, efficiency. Folding props reduce drag. The other trick mentioned in the video is the propeller prop pitch is different between inner and outer motors. Inners are optimized to offer better hover performance, and the outers offer better fixed wing cruise performance.
This is such a great video Nicholas! Really cool take on this problem. Your video format and information, like that about certain aerodynamic aspects of the design, add a lot. Keep it up!
I can't wait to see this with a much faster transition mechanism so you could be a lot more dynamic with this awesome build. Really creative craft!!
have you thought about having the wings fold upward? You could then use a "simple" strap in tension to keep the wing in its flying configuration. Just realized you could take your existing drone and fly it upside down 🙂Nice project! Good luck!
I had the same thought: make the wings fold in the other direction, with a stop at the joint to take the load, rather than asking the actuator to take the load.
Great idea. I guess it will depend on whether there is a stability or software advantage in an anhedral versus dihedral configuration during the transition phase.
@@GodmanchesterGoblin Intuitively it seems this approach would make transition even less stable, with the center of mass now being above the center of lift. There might be ways to overcome that problem.
@@truejim Agreed - but software control can sometimes benefit from an inherently unstable system since the corrective actions may be more consistent across a range of situations.
@@truejim : That's the way I see it too. It might prove simpler to have a latch at the fully unfolded position. That is assuming there is a need for anything... if the linear actuator is not back-driveable, and it doesn't need to suck battery power to stay unfolded, I guess you would leave it alone.
Incredibly cool! The VTOL transition stuff is so fascinating and satisfying to me. :)
You came to the right place then!
Such a creative idea! Loved every part of the video including the smart fly testing and cant wait for part 2
What a delight. Thanks. Looking forward to part II.
Your stuff is always so creative. And you do quality construction. Keep it up!
Appeciate it!
Dude this is awesome, such a good idea and it looks like something from Star Wars. Theres so many folding ships they have. Cant wait to see this design optimized and flying well! And whatever else you think up!
As far as Star Wars ships goes, this probably looks closest to an upside down "V-19 Torrent Starfighter".
Amazing attention to design and construction details and solutions. It's clear that you will take this concept to its highest level and determine its pros/cons. Looking forward to the next video!
Thanks!!
This seems very similar with the X-P4 Transwing project and it's awesome to see the difficulties face when doing such a project and made me appreciate so much more the idea
With it being partially folded like that, it can't help but remind me a bit of Star Wars' V-19 starfighter! That aside, seems like a cool build!
I can't even count the amount of times I said "WOW" in astonishment! You're brilliant my good sir. It's a pleasure to watch this process👌
Really appreciate the compliment, thanks!
Man, I can't wait to see it fully transition. Great video.
Marvelous glimpse of a great engineer at work. Much respect.
The best vtol+unfolding winged quadcopter I've see is the PteroDynamics X-P4 Transwing. Their design is ingenious, especially the transition.
Was going to mention them, most promising design I’ve seen of a vtolwing
Yeah the twist is real nice, makes it you don't have to sit on the tail. I wonder how much the mechanism weighs, though... Also, lack of hover efficiency is a concern for them as well as for nicholas
@@ardaricus1566 The PtroDynamics's transition genius is that fuselage stays flat regardless of flight mode, just like a V-22 osprey, but with the added quadcopter dynamics. And the folding joint is mechanically sound.
Hover efficiency is not important as it's inherently inefficient anyway, hence the need for winged flight mode. Even so, the tilt in their quad-copter mode is maybe 5 degrees, so no reason it's much more inefficient that the standard quadcopter.
Not that you had problems with the wings buckling, but I wonder if is there any cons in folding the wings the other way. They wouldn't make it weird for landing, since it lands on it's "side" and could add a lot of strength to the joints, but I have no Idea if while half folded as a upside down V/U it would be less stable than a right side up V/U. If you could enlighten me about that, i'd appreciate it.
I actually considered that and agree it would probably make the joint much stronger when fully deployed! I figured the dihedral could help through the transition, so that's why I decided to fold them down rather than up
@@NicholasRehm You can always just reverse the controls and fly 'inverted.'
@@toolbaggers That would make it difficult given the lift forces when in forward flight.
Not sure such extreme anhedral would be a good idea. It would probably just flip over
@@HonestAuntyElle would the lift forces actually help the wings open out into forward flight position? The issues I would see is folding back down to vertical flight you would be fighting against that lift.
Great work and it’s very satisfying to see it transition.
I think the thing that always comes back to bite tail sitters in the end is guesting conditions. Ultimately for large scale vtolwings I think just 4 motors on poles that rotate is the answer,
Great work and very inspiring. On my shop bench is my first attempt to incorporate your controller into a tailsitter. Looking forward to your next posts!
Sweet!!
I was waiting for this video, but, honestly I wasn't expecting that. Very interesting choices... I'm waiting for full forward flight, and... lots of performance data! 🙂
Also, Graupner makes quality folding L & R props form carbonfibre and glassfibre - I can recommend them.
Do you have link to any counter rotating sets? I can't find any in their catalog, maybe not looking hard enough
@@NicholasRehm you will be better of contacting graupner and asking them for a reseller. I find them locally and never online. You're looking for CAM FOLDING PROP.
Nifty idea with the prop mounts, I might just shamelessly steal that for my own VTOL project. Can't wait to see the full transition! I'm also quite curious about your method of blending controllers on this. Good luck with the project:)
I basically copied my approach from my last video on tailsitter transitions to fade between flight modes. Unfortunately, I think that simplified approach needs some tweaking to work with a morphing wing
@@NicholasRehm Interesting, that was also a great video by the way. Did you also adjust the motor mixing basf on the position of the wing folds? I cound imagine the pitch authority will get smaller as the motors come closer to each other as looked on from the side. Or is the craft tilted far enough to be out of the stall regime where this becomes noticible?
The controller part of it is defintely a challenge as I found out from my folding wing tailsitter concept a while ago. It seemed like I had to switch to using quaaternions vs euler. Pterodyanmics concept solved that by not having to transition their IMU from vertical to horizontal.
Great work! In the transition state, the control surfaces change from rudders only to V-tail then elevons. I'm not sure if the tilting angle is enough to determine the current state or if an airspeed sensor is a must.😁
Awesome video, First time viewer and I was incredibly impressed with the quality of your video, I liked, subscribed, and shared your video with a few people. You got a good laugh out of me with your commentary on almost wiping out the first time 😂 keep it up man 🤙
Many thanks!!
Love watching your stuff! Stopped my entire morning to sit down with this video lol
My guess is that during your transition, you're getting stalls at the tips of the wings and losing control authority from the aileron on the side of the stall. I'd venture that pitchAttitude + transitionWingDihedral > criticalAngleOfAttack. Combining those two angles obviously isn't a simple sum but I think you get my drift. Also, I bet that in a bank, the higher wing is stalling first, causing the bank to reverse, causing the other side to stall, and then you get into the observed oscillatory feedback loop
Solution space I'd say is either a) redesign the wing to twist slightly as it gets closer to the tip to reduce AoA, or b) just slap some vortex generators on the outboard sections to increase the critical angle of attack.
All in all though great video! Love seeing you draw inspiration from ThinkFlight, Tom Stanton, etc. Waiting eagerly for Pt 2!
That's a good point. There's probably some serious pitch/roll coupling going on with all that dihedral and no fin.
This might be on point. I did some intern work at NASA 35 years ago on stall triggering devices, to enable flight at very high angles of attack without losing control. We tested a number of things, including vortex generators, "bug splitters" (wedges of sheet metal sticking out the front of the wing surface), roughening strips (like, 40-grit sandpaper) to energize the flow at different positions on the leading edge and upper surface, drooped leading edge segments in front of the ailerons (to decrease the local AOA), wing twist, leading edge slats, and more. It's an art, as much as a science; it was a matter of playing around to find the best solution for a given design.
It almost seems like the best answer is simply higher speed in the partially-transitioned configuration to quickly get past that stalled regime, and only then transition the wing fold the rest of the way. Creeping up on the transition at slower speed is going to make things worse, I think.
USNTPS FTM-103 (I mentioned in a previous comment) has a good section on stall issues.
I’ll see if I can straighten it out in software, but some hardware tweaks like you suggested are definitely on the table
@@NicholasRehm A potential starting point here ua-cam.com/video/kA1ENhxLqTo/v-deo.htmlsi=8Hok6ABoFGeW9CZr
These guys have a similar AOA during transition, might be able to replicate their transition
Reminds me of the Ptero Dynamics Transwing drone, but theirs has the entire wing rotate in a unique way. Would be interesting to see a comparison of the two ways of approaching the same problem.
I thought the same... then thought this design might actually breach their patent as I believe its pretty comprehensive regarding the unfolding/rotation of complete wing assemblies when transitining from a VTOL to forward flight modes. Not sure if it would matter unless he is selling the design, but could be complicated if he makes money from the video on UA-cam
We also thought the same, although it's definitely infringement on Amazon's "In-flight reconfigurable hybrid unmanned aerial vehicle" US patent 9550567B1. We had a UA-camr infringe on our patent and never got a response back. He only stopped replying to comments, but he can be held liable for any funding which is more likely the only goal.
@@DinGuScoTrue. They seem pretty chill though. They're open to other people using their patent.
I think I can claim dibs on the folding wing concept 11 years ago for a DARPA’s Uavforge competition.
ua-cam.com/video/qya7MXR-rS0/v-deo.htmlfeature=shared
I couldn’t patent cause I worked for an aerospace company. Pterodynamics concept is different and better and glad to see its progress!
gorgeous build
Great idea, most importantly even greater execution! Well done, nice editing! Definitely earned a sub in one video:)
Instead of having the wings fold up in a “U” shape, you could have them fold down in an “n” shape. This would make it stronger in the plane orientation because the bending forces would be fighting against a mechanical interference instead of the strength of the servos.
glad someone said it!
I have built and flown the N shape. It worked, sort of, but had some problems. When hovering close to the ground yaw was uncontrollable because any cross wind makes it spin like the cup wheel of an anemometer.
That’s the most StarWars thing I’ve ever seen, love it! 😮
I find myself accidentally building Star Wars looking things a lot lately… haha
I suggest to put the wing-hinges different from 90 degrees such to have the wings v-shape backward, like traditional flying wing designs - this will give much more stability for unfolded flying. To boot, you have have the propellers at same level when in drone configuration.
This is a really cool project - good luck and load of success!
Awesome! I'm working on tailsitter project myself for my PhD and I find inspiration in your videos
Sweet!
1:20 Just maker a circular wing so it is endless efficient xDD
Very cool setup. Have you attempted any flights fully unfolded just to see how it handles as a flying wing without needing to risk a crash mid transition?
Such an amazing and challenging project. The recoveries from semi-transition back into hover mode are just amazing (and a scary) to watch. That you're able to recovery so well is an attestant to your skills and all the effort that have gone into developing dRehmFlight.
My brain is twisting as I try to imagine how pitch is controlled/maintained as wings unfold. Wonder if had an elevator, or elevons on the inner wing would help? Such flight surfaces operate similar to flight to those on a tail sitter, reducing the complexity of the outer controls surfaces having a wide transition angles. (swapping between rudders/elevons as pitching, while moment forces from the motors also changes)
The closest transitioning VTOL that tries similar unfolding transitions is the PteroDynamics Transwing. Its wings rotate and pivot the using a heavy complex mechanism.
The dReamFlight folding quad wing VTOL is much simpler mechanically, but a more complex software challenge.
This is phenomenal! Very inspiring, id love to build this! Tho id probably tweak the design to look even more like the lambda t-4a shuttle. Great editing. Keen for part two!
ua-cam.com/video/I3D559DNa04/v-deo.html
Love it. Great conclusion & clever design.
Amazing project, your skills are impressive, hope to see this on the market in a couple of years.
This is such a cool idea! Nice work!
this is some brilliant work
Looks amazing, looking forward to your advances.
I love the idea behind this!!! Please keep it up!!!
Thanks, will do!
as somebody who builds his own aircrafts to fly myself - you earned that sub! jesus the transition was so nice to watch
This is pretty amazing Nicholas. Subscribed!
you hit the nail on the head with this one! you should see if you could patent this. Good job!
Thanks!
This is sooo Coooool!!!! Looking forward to Part 2!!!
Really excited for part 2, great video!
Appreciate it!
This is so cool! Really enjoy seeing your work!
Appreciate it!!
Wonder of all these experiments and innovations in drone design will benefit future manned aircraft design. Please keep up the good work.
Very interesting design. The oscillations may be from having a lot of weight on the wingtips. I discovered this when making a small paper based kite, just for fun. The kite was a traditional diamond shape but bowed using tension from a thread from wing tip to wing tip and secured with rings made from copper wire which I had handy. I had oscillations like yours on its first test flight which went away completely when the copper rings were removed. The fibreglass looks great. Maybe you could compensate for the weight increase by reducing some of the base wing material?
Looks like a very strong dihedral effect during the transition. It goes into a rapid dutch roll. It needs much tighter yaw control during transition so the unfolding wingtips don't get a chance to generate a lot of rolling moment.
Agreed, need to tweak some of the flight controller gain staging to clean it up
This was the best sponsor integration i've ever seen. And thanks for the video, very nice indeed
Me & @PCBWay appreciate that :)
Awesome! Thanks for the video!
You make such magnificent flying machines.
Very nice work, lots of thinking involved fore sure
Quite fascinating, can't wait for part 2 😁
The 3D transparent overlay over the footage is really nice!!
Thanks!!
That is extremely cool! Can't wait to see the next video.
amazing as always! I need to look into making something like this!
Awesome work🎉. Can't wait to see the next vid
What a cool configuration
best thing I've seen on internet today, literally a master piece 🔥
Insanely cool! Staying tuned in :D
I think it might increase forward flight stability if the wingtips were swept back. Maybe the hinges can be at an angle? In the straight configuration it has very low pitch moment and the elevons have little moment arm. Kavin's wings all had some sweep; gliders with wings that shape need a tail.
Static instability is a feature, not a bug ;)
@@NicholasRehm Well that's a very ambitious control task then! I'm looking forward to seeing how this performs relative to Tom Stanton's latest tiltrotor. Perhaps you can devise some kind of VTOL challenge? =)
Good job! The project has a place in life.
This thing looks straight outta Star Wars! Watching it transition for the first time blew my mind.
Way cool! Loads of potential in the desing.
What an awesome project!
THATS FRIGGIN COOL GOOD JOB MAN!
Dope in many many ways sir!
Badass dude!! You’re doing all of the flight configs I wish I had time to play with.
Eagerly awaiting the final product here. I truly think this is the most efficient VTOL concept out there. A future state could even reduce the servos to one with some push rod and gearing action for a slight weight reduction.
I’d be curious also to see some side-by-side performance data with all 4x motors running vs just the 2x outboard. My gut would say you probably gain a little efficiency by running them all at slightly reduced throttle than the 2x config at slightly increased throttle. Not to mention the yaw control is nuts when only using the 2x outboard motors. A motor-out scenario would be catastrophic if not hilarious to watch at Rc scale lol. Chance of survival in a motor out scenario goes way up if 1/4 go out as opposed to 1/2, I imagine
I'll definitely test power with all 4 vs only outer 2 in forward flight
Awesome design, and video!
Excellent video as always! Such a joy to watch!
Thanks Dave!
I've had a similar idea that I've been floating around for a while. I was thinking to use a membrane (like nylon) that is unfurled and pulled taut with thin stranded cable, kinda like a kite. This would keep the drag minimal during copter flight and then when pulled taut it would act as a wing for lift
amazing channel. some of the coolest flight stuff i have ever seen.
Thanks!!
This is a fascinating design. Congrats.
For better stability: Since the ailerons are very far apart, consider adverse yaw reduction and only use upward aileron - no down - for roll control - this will also help with yaw in that direction as there is more drag there - and less on the "up" going wing as that aileron will remain neutral. Since you already have separate actuators for each aileron you're "there" other than the s/w.
You did an amazing job !
Very interesting and inspiring concept!
Never fails to fails to amaze me the ingenuity and dedication of some UA-camrs. This is brilliant and look forward to the transition flight, don't know nothing but would a vertical stabilizer help stabilize the transition?. 👏🏻
Appreciate it--more vertical stab would certainly help add some passive stability
Very neat solution to counter-rotating folding props!
FWIW, APC makes two "folding pusher" (counter-rotating) props.. 5x5 and 9x5.
And if you've got the power, you could try transitioning into "forward" flight by accelerating straight upward while unfolding the wing rather than trying to do it horizontally. The oscillations you're getting at half unfolding look like dutch roll oscillations. They *should* go away when the wing is full flat, but going to be annoying to get past.. without going straight up.
Good find!
i love it! cant wait to see the next.
Such a great project
Bro this stuff is fire!!!! New Sub!
This is sick. I can’t wait for the next update
wow, great design dude! I have to build this
Oooooo this is so cool!! I’d love to see what your list of video ideas look like😂. The things you come up with are awesome.
Dude your new vid is awesome too!
@@NicholasRehmThanks man!
Looks like Dutch roll! Awesome video