I had a little bit too much fun doing some video transitions: ruclips.net/video/uxb8ACWtDkI/видео.htmlsi=BhoITlYh0DR6NczF&t=50 (similar project, btw.) Next time, an X-ray overlay. Great idea.
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.
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.
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
Guys like you here on RUclips 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.
If i may humbly suggest using a mechanism that builds up and releases tension to assist with motor transitions-similar to a crossbow slowly drawing back, then snapping forward. The stored energy can help unfold wings or other flight components quickly, overcoming wind resistance. Long time engineer, just getting into programming, but have preformed avionics repairs professionally. Excited to build some quad coptors with my kid from scratch.
@NicholasRehm That’s a great point! I was looking at the framework shown at 3:04 and thinking of a minor adjustment. Instead of adding many components, the plan would involve changing the wing joint's gear ratio, adding an internal cylinder to house a ratcheting spring or rubber band, and using the existing actuator. A small additional servo could be added to reset the ratchet and release the wings for re-folding. The new components would be minimal: light fishing line for the cable, the internal cylinder as negative space inside the wing, and lightweight rubber bands or springs. Are there any concerns with thrust and lift? It seemed like the power output was sufficient, I am curious how tight your weight ratio is now. If you trust random Google Doc links, I tossed a quick sketch with my outline in blue. Its a morning coffee quality doodle, just to get seek perspective on the implications of the weight penalties. drive.google.com/file/d/1nyM1ORi6uhWuGWod22X4buey0zI3kKcD/view?usp=sharing
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!
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.
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.
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!
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.
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.
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.
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.
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
@@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.
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 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.
@@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.
Reverse the body locstion. the wings swing out and down as the craft transitions to forward flight? The hinges would be simple and dramatically stronger AS PASSIVE STOPS WILL CARRY THE LOAD. The motors always point in the correct orientation for tractor or pusher configuration.
360 camera plus gyro for retaining orientation plus fpv = perfect irl flying 3rd person camera. Could even be made thin enough to slip into a backpack.
Alternative: - 2 wing tips props, 1 tail prop - wing can rotate 90 deg - tail section can rotate 90 deg VTOL: wing and trail rotated vertically, works like 3 props drone Normal flight: wing and trail rotated horizontally. Maybe tail prop can collapse (and be drawn into the tail section perhaps with a cone on the prop closing to make it more streamlined). Might need large flaps on the tail to counter it pitching up as the tail transitions. Would love to see one! Hope you're well.
I'm not an RC plane guy, but I do live in the R&D world. The printing issues you are having are not down to just settings, but it also looks like you are having a moisture issue. I would highly recommend a dryer for your filament, which also acts as a pre-heater. The AMS on the X1C has no active heating and relies on a consumable desiccant packet that is not used evenly. Since the desiccant does not move, the outer pellets get used up while the inner are blocked. There are kits to mod the AMS with a small heating element to maintain a constant temperature inside the AMS. On our X1C, I have not been allowed to mod the AMS to have the heater, so I've added 3D printed desiccant pods that screw together inside each spool. This has kept up with our high humidity very well. As a bonus, filling the pods only 3/4 the way full also mixes the pellets as the spool turns, allowing the pellets to be used evenly. I used a color changing pellet, so when they are close to their maximum absorption, the pods are placed on the build plate, or on a sheet spaced off the build plate. The build plate is then heated to bring the internal air temperature of the chamber to 60 to 80C to bake the spools. This releases the water that the pellets absorbed. Every so often during this process, the pods are spun and placed back on their other end. This moves the pellets around and allows the hot, humid air out. This this method, we have not had to change the desiccant in the AMS since the pods were installed. Since the AMS is not the end all, be all of filament delivery, we also have a stand alone filament drier hooked into the X1C between the AMS and the feed input. This was as simple as printing a Y adapter and fitting everything up with Capricorn tubing and quality fittings. This does mean you have to manually load the filament from the drier, but if you are only using the one filament, that's not a big deal. This does give fine control over the storage and preparation conditions of the filament prior to printing. This makes printing with stuff like PEEK, TPA, PC, and the light weight PLA much easier and more consistent. One last point on my already long rant is a controversial one. But, it's one I've found very useful for structural prints. The prints greatly benefit from a post print annealing cycle. I know over the past few years, people have tried various methods to strengthen parts by using a powered substance to pack in and around the print, then bake the print at or slightly above the plasticizing temperature. While this can work, I don't think the rick and effort is worth the reward. What most people don't understand is that the plastic does not instantly go from solid to goo when you jump a degree at some point. The softening is more of an exponential curve, as is the plastic's strength. So, you can heat the print to a temperature higher than its operating temperature, but well below its plasticizing temperature, and increase the strength of the print in both the X/Y and Z planes. Bambu Labs even has a couple white papers on this. Plus, you can do this in your printer. You just need a rigid plate placed over the build plate, with a space between them. You will need some trial to get the build plate temperature perfect for the chamber's air temperature. You are shooting for a chamber temperature half to 2/3 the "melting" temperature of the material. This is held for 6 to 12 hours to allow the discontinuous plastic to naturally bond through various internal forces. When properly done, you will have a less brittle, but stronger print. This does take a while, so if you are not wanting to tie up you printer this long, you can always opt to get a cheap lab grade oven and add a PID to it. You can get a new oven with a volume slightly greater than the build volume of the X1C and a PID system for under $200.
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!
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.
@@NicholasRehm A potential starting point here ruclips.net/video/kA1ENhxLqTo/видео.htmlsi=8Hok6ABoFGeW9CZr These guys have a similar AOA during transition, might be able to replicate their transition
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!
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 RUclips
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 RUclipsr 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.
I think I can claim dibs on the folding wing concept 11 years ago for a DARPA’s Uavforge competition. ruclips.net/video/qya7MXR-rS0/видео.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!
Awesome build dude. Really inspiring your ability to r&d solutions to the efficiency under diverse conditions and altitudes issue. Happily subscribed! Also, do carbon rods function similarly to steel rod just lighter? Are there any differences in performance of the pivoting parts?
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.
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.
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?
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!
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.
Your oscillation is divergent control loop to Dutch roll coupling. You'll either need to slow down the hand off between VTOL and aerodynamic control, or change the entire speed of your transition; likely either slower rotation, faster wing deployment, or a transition in more of a 45° climb using ascent rate as the speed handoff between quad control and aerodynamic control. Really cool design! Although sweep is a slightly less efficient planform, it could be made up by a higher performance airfoil transition negative Cm/ high lift at the root with washout/ and natural or positive Cm at the tips. A horten style center section could still allow tail sitter functionality and prop clearance with trailing edge. Side benefit is it would relieve the tip motors of a substantial amount of their workload maintaining directional stability, and instead can be mixed as a proverse yaw solution instead of active stability management. This can drastically increase the efficiency of your motors as well.
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.😁
If you don't unfold completely this would act like dihedral and naturally keep the roll axes more stable Also adding it might be worth wile to try a swept back wing configuration allowing more angular virginity for the winted motors and providing needed space on the center wing for passive vertical stabilization
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 looks like a production piece right off the line. When they first started playing with the concept of 3D printing they called the machine a Rapid Prototype machine. And you prove that name in fact. What a great presentation.
Hi. Free advice. Make it as M form. But central corner of M should be in the center of square. It will compensate centric problem. The upper corners of M and bottom endings are 4 engines. Top corners of M are movable up in the air (not down like in Your model). The airflow will help to unfold wings.
Making the craft a chevron will stabilise the intermediate stability issues somewhat, but I dont know drones. I spent a portion of my childhood trying to make The Smallest Kite In The World, trying everything from a full delta to a box configuration. I also designed a folding kite-to-glider delta with a string release - the problem you are having is angle of attack, in an aircraft this is a stall condition and usually causes a crash, it is to be avoided. Good luck with this project, tho I feel you are going to need it. 😉
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
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,
Very interesting tailsitter approach and great job so far! I have a few thoughts/questions based on some previous tailsitters I've messed with: 1. Have you considered variable pitch propellers? Could allow you to feather the props without needing to fold them, plus it would solve the issue with the compromise between hover and forward flight performance 2. Having all 4 motors in tractor config might be better since the blown wing reduces stall speed down to effectively 0 (which is probably a factor for you during transition) 3. Unless your flight controller is setup to run quaternions you are going to start getting very weird behavior near 90 degrees in the pitch axis (technically true in roll, but less of a concern). It might be best to turn off auto level for your transition testing
1 - Definitely a good option to better performance, just not at this scale. 2 - maybe, but as long as the wing is even slightly folded, I get get full roll/pitch/yaw control through the motors--no need to rely on aero control or a stalled wing. 3 - Yes I have a quaternion attitude estimate, I convert that to euler angles for my pid controllers, but fade between reference attitude as I do the pitch over; check out my last video for more details on that
I wonder if a folding "H" shape could be better. I mean, the "U" shape places the central pod off center when hovering - not good if you wanted a payload. But an "H" shape would place the central pod in the center. So, in hover it's like a biplane, and you can transition to a biplane horizontally. But then, the wings can rotate flat against the center spar. Because these wings are centered around the pivot point, you wouldn't need very strong servos to do the rotation.
Some advice. Don't worry about "transitioning" smoothly from vertical to horizontal in a linear manner. In r/c helicopter when we "invert" there is absolutely no safe linear transition from regular to inverted. We just go into a well practiced "suicide" flip. It's all in the skills of your finger, plus mental orientation reversal control. Of course, we practice many times on the simulator until it becomes an "instant reflex" with no fear/no hesitation. So, if it's feasible with your aircraft, figure out a maneuver that will work. Then practice or "program it". Go up high, then go into a controlled spiral dive that has some lift, and simultaneously "unwrap" the wings. Then, fly out of it. This will require skill, ofcourse, but allows you to skip the "transitional" vertical to horizontal engineering project complexity.(just research the US army V-22 Osprey development, it's still unpredictable). Also, perhaps, ditch all the wing actuation, and simply spring load and cable it so you have a very light weight instant wing lock. Ofcourse, you are limiting the aircraft to Vertical take off, but horizontal landing. However, it's always best to divide development into feasible phases. Good luck.
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?
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!
You could increase aspect ratio by adding yet another foldable Wing on the end. To have a closed square. It is just the Question if it is worth the additional weight. But you could re-use the construction of the existing joint. 🎉 Awesome Design Work!
Dude. I hope this gets enough views for it to become worth it for you to keep producing these videos. I keep waiting for an update. RUclips keeps showing me this video. PART 2 PLEASE
Have you considered folding the wings down instead of up? This way you can use the strength of a fully extended joint to support the weight instead of relying entirely on the actuator’s holding force. You can have the spar extend a bit beyond the joint axis and lock onto the other spar for additional strength.
Never fails to fails to amaze me the ingenuity and dedication of some RUclipsrs. This is brilliant and look forward to the transition flight, don't know nothing but would a vertical stabilizer help stabilize the transition?. 👏🏻
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!
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!
Shout out to @xjet! I remember that video! Thanks for getting me into all this, Bruce! Your science-heavy reviews walked so Nicholas, Thinkflight, RC Testflight, etc. could run.
Holy moly that is a cool idea! As an electrical engineer, it would be interesting to develop some mathematical model for this hybrid drone and try to figure out possible parameter values to stabilize it in the various states of its operation. This might give better initial values to start with and possibly avoid some crushes :)
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.
@@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? =)
If you really want to focus on efficiency in flight I recommend reducing the chord towards the wingtips to get a more elliptical lift distribution. For a straight wing, usually a taper ratio of 0.4 gets you pretty close to elliptical. This also has the effect of increasing the aspect ratio even further. This might however not be structurally viable, but that depends on how much of the loads are carried by the carbon spar vs the actual airfoil.
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: ruclips.net/video/uxb8ACWtDkI/видео.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.
I can already imagine the full transition looking totally majestic! Really excited to see part 2, great work 👍💕
Thanks!!
Guys like you here on RUclips 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.
If i may humbly suggest using a mechanism that builds up and releases tension to assist with motor transitions-similar to a crossbow slowly drawing back, then snapping forward. The stored energy can help unfold wings or other flight components quickly, overcoming wind resistance.
Long time engineer, just getting into programming, but have preformed avionics repairs professionally.
Excited to build some quad coptors with my kid from scratch.
Very good idea, maybe applied to a slightly larger version so the weight penalty of the additional components is less pronounced
@NicholasRehm That’s a great point! I was looking at the framework shown at 3:04 and thinking of a minor adjustment. Instead of adding many components, the plan would involve changing the wing joint's gear ratio, adding an internal cylinder to house a ratcheting spring or rubber band, and using the existing actuator. A small additional servo could be added to reset the ratchet and release the wings for re-folding.
The new components would be minimal: light fishing line for the cable, the internal cylinder as negative space inside the wing, and lightweight rubber bands or springs. Are there any concerns with thrust and lift? It seemed like the power output was sufficient, I am curious how tight your weight ratio is now.
If you trust random Google Doc links, I tossed a quick sketch with my outline in blue. Its a morning coffee quality doodle, just to get seek perspective on the implications of the weight penalties.
drive.google.com/file/d/1nyM1ORi6uhWuGWod22X4buey0zI3kKcD/view?usp=sharing
So where is part two. Im wanting more
After 5 months I'm guessing this channel is dead 💀☠️
Stroke
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!
Can't wait for part 2 this is quite possibly my favorite project of yours yet. Such an amazing awesome design
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!
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.
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.
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".
Any updates yet?
No😢
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.
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!
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.
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.
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.
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!!
This video is so well made and I love the design. Can’t wait for the next part!
Many thanks!
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.
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
Wow. Good on you for being patient with the forward flight transition and taking the time to tune. Keep going!
it looks like darth vader spaceship when it's unfolding!! Good job!!
Reverse the body locstion. the wings swing out and down as the craft transitions to forward flight? The hinges would be simple and dramatically stronger AS PASSIVE STOPS WILL CARRY THE LOAD. The motors always point in the correct orientation for tractor or pusher configuration.
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!
360 camera plus gyro for retaining orientation plus fpv = perfect irl flying 3rd person camera.
Could even be made thin enough to slip into a backpack.
Nice save @ 9:00. Can't wait for the next video.
Hah, thanks!
Alternative:
- 2 wing tips props, 1 tail prop
- wing can rotate 90 deg
- tail section can rotate 90 deg
VTOL: wing and trail rotated vertically, works like 3 props drone
Normal flight: wing and trail rotated horizontally. Maybe tail prop can collapse (and be drawn into the tail section perhaps with a cone on the prop closing to make it more streamlined).
Might need large flaps on the tail to counter it pitching up as the tail transitions.
Would love to see one! Hope you're well.
damn bro went balls deep with this design he forgot to post another vid
I'm not an RC plane guy, but I do live in the R&D world. The printing issues you are having are not down to just settings, but it also looks like you are having a moisture issue. I would highly recommend a dryer for your filament, which also acts as a pre-heater. The AMS on the X1C has no active heating and relies on a consumable desiccant packet that is not used evenly. Since the desiccant does not move, the outer pellets get used up while the inner are blocked. There are kits to mod the AMS with a small heating element to maintain a constant temperature inside the AMS. On our X1C, I have not been allowed to mod the AMS to have the heater, so I've added 3D printed desiccant pods that screw together inside each spool. This has kept up with our high humidity very well. As a bonus, filling the pods only 3/4 the way full also mixes the pellets as the spool turns, allowing the pellets to be used evenly. I used a color changing pellet, so when they are close to their maximum absorption, the pods are placed on the build plate, or on a sheet spaced off the build plate. The build plate is then heated to bring the internal air temperature of the chamber to 60 to 80C to bake the spools. This releases the water that the pellets absorbed. Every so often during this process, the pods are spun and placed back on their other end. This moves the pellets around and allows the hot, humid air out. This this method, we have not had to change the desiccant in the AMS since the pods were installed.
Since the AMS is not the end all, be all of filament delivery, we also have a stand alone filament drier hooked into the X1C between the AMS and the feed input. This was as simple as printing a Y adapter and fitting everything up with Capricorn tubing and quality fittings. This does mean you have to manually load the filament from the drier, but if you are only using the one filament, that's not a big deal. This does give fine control over the storage and preparation conditions of the filament prior to printing. This makes printing with stuff like PEEK, TPA, PC, and the light weight PLA much easier and more consistent.
One last point on my already long rant is a controversial one. But, it's one I've found very useful for structural prints. The prints greatly benefit from a post print annealing cycle. I know over the past few years, people have tried various methods to strengthen parts by using a powered substance to pack in and around the print, then bake the print at or slightly above the plasticizing temperature. While this can work, I don't think the rick and effort is worth the reward. What most people don't understand is that the plastic does not instantly go from solid to goo when you jump a degree at some point. The softening is more of an exponential curve, as is the plastic's strength. So, you can heat the print to a temperature higher than its operating temperature, but well below its plasticizing temperature, and increase the strength of the print in both the X/Y and Z planes. Bambu Labs even has a couple white papers on this. Plus, you can do this in your printer. You just need a rigid plate placed over the build plate, with a space between them. You will need some trial to get the build plate temperature perfect for the chamber's air temperature. You are shooting for a chamber temperature half to 2/3 the "melting" temperature of the material. This is held for 6 to 12 hours to allow the discontinuous plastic to naturally bond through various internal forces. When properly done, you will have a less brittle, but stronger print. This does take a while, so if you are not wanting to tie up you printer this long, you can always opt to get a cheap lab grade oven and add a PID to it. You can get a new oven with a volume slightly greater than the build volume of the X1C and a PID system for under $200.
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 ruclips.net/video/kA1ENhxLqTo/видео.htmlsi=8Hok6ABoFGeW9CZr
These guys have a similar AOA during transition, might be able to replicate their transition
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!!
Your stuff is always so creative. And you do quality construction. Keep it up!
Appeciate it!
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!
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 RUclips
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 RUclipsr 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.
ruclips.net/video/qya7MXR-rS0/видео.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!
Awesome build dude. Really inspiring your ability to r&d solutions to the efficiency under diverse conditions and altitudes issue. Happily subscribed!
Also, do carbon rods function similarly to steel rod just lighter? Are there any differences in performance of the pivoting parts?
Incredibly cool! The VTOL transition stuff is so fascinating and satisfying to me. :)
You came to the right place then!
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
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.
This thing looks straight outta Star Wars! Watching it transition for the first time blew my mind.
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?
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!!
1:20 Just maker a circular wing so it is endless efficient xDD
Awesome! I'm working on tailsitter project myself for my PhD and I find inspiration in your videos
Sweet!
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.
Your oscillation is divergent control loop to Dutch roll coupling. You'll either need to slow down the hand off between VTOL and aerodynamic control, or change the entire speed of your transition; likely either slower rotation, faster wing deployment, or a transition in more of a 45° climb using ascent rate as the speed handoff between quad control and aerodynamic control.
Really cool design! Although sweep is a slightly less efficient planform, it could be made up by a higher performance airfoil transition negative Cm/ high lift at the root with washout/ and natural or positive Cm at the tips. A horten style center section could still allow tail sitter functionality and prop clearance with trailing edge. Side benefit is it would relieve the tip motors of a substantial amount of their workload maintaining directional stability, and instead can be mixed as a proverse yaw solution instead of active stability management. This can drastically increase the efficiency of your motors as well.
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.😁
If you don't unfold completely this would act like dihedral and naturally keep the roll axes more stable
Also adding it might be worth wile to try a swept back wing configuration allowing more angular virginity for the winted motors and providing needed space on the center wing for passive vertical stabilization
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.
as somebody who builds his own aircrafts to fly myself - you earned that sub! jesus the transition was so nice to watch
This looks like a production piece right off the line. When they first started playing with the concept of 3D printing they called the machine a Rapid Prototype machine. And you prove that name in fact. What a great presentation.
I really appreciate the nice words
Hi. Free advice. Make it as M form. But central corner of M should be in the center of square. It will compensate centric problem. The upper corners of M and bottom endings are 4 engines. Top corners of M are movable up in the air (not down like in Your model). The airflow will help to unfold wings.
Making the craft a chevron will stabilise the intermediate stability issues somewhat, but I dont know drones. I spent a portion of my childhood trying to make The Smallest Kite In The World, trying everything from a full delta to a box configuration. I also designed a folding kite-to-glider delta with a string release - the problem you are having is angle of attack, in an aircraft this is a stall condition and usually causes a crash, it is to be avoided.
Good luck with this project, tho I feel you are going to need it. 😉
Man, I can't wait to see it fully transition. Great video.
Never seen this guy before, by the title and concept fully expected a brit
This was the best sponsor integration i've ever seen. And thanks for the video, very nice indeed
Me & @PCBWay appreciate that :)
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
You're a wizard Nicholas. You make it look easy--a true testament to your skill.
haha many thanks
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,
Very interesting tailsitter approach and great job so far!
I have a few thoughts/questions based on some previous tailsitters I've messed with:
1. Have you considered variable pitch propellers? Could allow you to feather the props without needing to fold them, plus it would solve the issue with the compromise between hover and forward flight performance
2. Having all 4 motors in tractor config might be better since the blown wing reduces stall speed down to effectively 0 (which is probably a factor for you during transition)
3. Unless your flight controller is setup to run quaternions you are going to start getting very weird behavior near 90 degrees in the pitch axis (technically true in roll, but less of a concern). It might be best to turn off auto level for your transition testing
1 - Definitely a good option to better performance, just not at this scale. 2 - maybe, but as long as the wing is even slightly folded, I get get full roll/pitch/yaw control through the motors--no need to rely on aero control or a stalled wing. 3 - Yes I have a quaternion attitude estimate, I convert that to euler angles for my pid controllers, but fade between reference attitude as I do the pitch over; check out my last video for more details on that
I wonder if a folding "H" shape could be better. I mean, the "U" shape places the central pod off center when hovering - not good if you wanted a payload. But an "H" shape would place the central pod in the center.
So, in hover it's like a biplane, and you can transition to a biplane horizontally. But then, the wings can rotate flat against the center spar. Because these wings are centered around the pivot point, you wouldn't need very strong servos to do the rotation.
man this is like a professional discovery channel show
Marvelous glimpse of a great engineer at work. Much respect.
I have been thinking about this for years, bravo! I look forward to see how this further develops!
Some advice. Don't worry about "transitioning" smoothly from vertical to horizontal in a linear manner. In r/c helicopter when we "invert" there is absolutely no safe linear transition from regular to inverted. We just go into a well practiced "suicide" flip. It's all in the skills of your finger, plus mental orientation reversal control. Of course, we practice many times on the simulator until it becomes an "instant reflex" with no fear/no hesitation. So, if it's feasible with your aircraft, figure out a maneuver that will work. Then practice or "program it".
Go up high, then go into a controlled spiral dive that has some lift, and simultaneously "unwrap" the wings. Then, fly out of it. This will require skill, ofcourse, but allows you to skip the "transitional" vertical to horizontal engineering project complexity.(just research the US army V-22 Osprey development, it's still unpredictable). Also, perhaps, ditch all the wing actuation, and simply spring load and cable it so you have a very light weight instant wing lock. Ofcourse, you are limiting the aircraft to Vertical take off, but horizontal landing. However, it's always best to divide development into feasible phases. Good luck.
you hit the nail on the head with this one! you should see if you could patent this. Good job!
Thanks!
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?
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 like this project 👍🏻
You make such magnificent flying machines.
What a delight. Thanks. Looking forward to part II.
You could increase aspect ratio by adding yet another foldable Wing on the end. To have a closed square. It is just the Question if it is worth the additional weight. But you could re-use the construction of the existing joint. 🎉 Awesome Design Work!
Dude. I hope this gets enough views for it to become worth it for you to keep producing these videos. I keep waiting for an update. RUclips keeps showing me this video. PART 2 PLEASE
Amazing project, your skills are impressive, hope to see this on the market in a couple of years.
this is some brilliant work
Have you considered folding the wings down instead of up? This way you can use the strength of a fully extended joint to support the weight instead of relying entirely on the actuator’s holding force. You can have the spar extend a bit beyond the joint axis and lock onto the other spar for additional strength.
Never fails to fails to amaze me the ingenuity and dedication of some RUclipsrs. 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
Fantastic project, cannot wait to see when the next update drops!
Such a creative idea! Loved every part of the video including the smart fly testing and cant wait for part 2
3:15 If you're looking for strength, consider using PETG instead of PLA. Great video, as always!
I've got a set of backup parts printed in CF-PETG!
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!!
This may be the only RUclips video where I've actually "smashed the like button"! And I was only one minute in!
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!
ruclips.net/video/I3D559DNa04/видео.html
This is so sick
This is sick. I can’t wait for the next update
I made something very similar in KerbalSpaceProgram and called it the Albatross. Great work man keep it up!
Shout out to @xjet! I remember that video! Thanks for getting me into all this, Bruce! Your science-heavy reviews walked so Nicholas, Thinkflight, RC Testflight, etc. could run.
Fun fact: Bruce shouted me out on his channel wayyyy back when I was starting out on youtube, helped my channel out a ton. Nice guy :)
Holy moly that is a cool idea! As an electrical engineer, it would be interesting to develop some mathematical model for this hybrid drone and try to figure out possible parameter values to stabilize it in the various states of its operation. This might give better initial values to start with and possibly avoid some crushes :)
Wonder of all these experiments and innovations in drone design will benefit future manned aircraft design. Please keep up the good work.
Super impressive engineering!!!!!!!! That thing sounds SCARY!
Thanks! Yes it does lol
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? =)
This is finally a good use of the folding wing design we see in star wars ships. Lock S foils to attack position!
We absolutely need to see a Lambda-class Imperial Shuttle from Star Wars using this folding wing idea 😂
I can see this having practical applications for real aircraft travel. For one thing it could be a great safety measure
If you really want to focus on efficiency in flight I recommend reducing the chord towards the wingtips to get a more elliptical lift distribution. For a straight wing, usually a taper ratio of 0.4 gets you pretty close to elliptical. This also has the effect of increasing the aspect ratio even further. This might however not be structurally viable, but that depends on how much of the loads are carried by the carbon spar vs the actual airfoil.
I considered taper but ran into issues of thickness at the tips that made cramming a spar in there difficult
Really excited for part 2, great video!
Appreciate it!
Isn't this a bit like a real life imperial shuttle from star wars lol, awesome work btw.
gorgeous build