Not neccesarily, the thrust lines of the engines could be an issue. When they are at the upper level of the aircraft's thrust/drag lines the engines should have up-thrust. Check out some of the amphibious aircraft designs with high mounted engines, they all have up thrust. Great trial.
This just reminded me that Samm Shepard died a few years ago and made me wonder what we have missed out on. He was one of the best youtube rc channels in my eyes
You could probably increase your wing performance if you put the propellers behind the wing. You get super smooth air coming into your super nice wings and then you proceed to make it all swirly and turbulent with the rotors.
I remember seeing Samm's video on this (god rest his soul, that beautiful man he was) and loving it a lot when it came out. Fast forward a few years and I'm a mech E at Gonzaga, and fluids dynamics is about to get into air volumes over planar and curved surfaces, and we talk a little bit about slots and flaps, of course I make the connection to this and bring it up in class, we all watch the video (he apparently showed it to his other classes too), and he goes on a 20 minute discussion about how this wingset works, with the calculus to prove it too. I miss taking fluids, that class was fun as all get out!
@@whitewolf6605 he was driving his motorcycle uphill on road where he used to speed up, but that road do not allow you to see what is at the top because the road surface up there gets suddenly horizontal. Unfortunately a new round about was built up there and he didn't see it in time to break safely, he crashed into it and died three days later....he left behind a loving family, a pilot carreer and a girlfriend that he had just started to date. RIP Sam
*Hey, rctestflight - I made one of these with a "V" tail so I could lift, dive and turn with only 2 servos. I also used a Dihedral Wing shape and it was 800% more stable with that Didedral wind keeping the plane flat. Even in high winds it remained stable. Nothing could knock it out of the sky as it automatically found the most stable flight direction even if you wanted it to turn, the design choose STABILITY for its flight direction! I may need a more powerful motor or just wait for days when the wind is under 20 MPH. AMAZING!*
When i was a kid my friends dad had a biplane, and i remember going for a ride in it. He though it was hilarious that we could fly slower than the traffic on the highway... I think the stall speed on his plane was something like 40 mph... It was pretty cool!
Awesome design, Daniel! Not only is it really fun, but I also thought it was beautiful as well! I had a few thoughts after watching this video: First, if you do a version 2.0, you might consider giving it a T-tail so that the horizontal stabilizer is in cleaner air. Second, this is probably terrible practice for a number of reasons, but I also have a CNC that I use for machining XPS sometimes, and I have found I can basically skip most of the roughing and be super aggressive on finishing passes with the foam. It saves lots of time, and it doesn't care. Just don't run one of those toolpaths on something stiffer than foam! When you fiberglass a wing, try using waxed mylar against the glass instead of peel-ply, and stick the peel-ply outside of that as a vacuum breather. You will get a shiny surface right out of the bag, and won't have to subject the part to the force of removing the peel-ply. Oh, and your plane is in good company when it comes to using elevons for roll control - the F-14 did too!
Maybe put the wings on a servo to rotate them while landing so you can change the angle of attack? They may need to move rearwards at the same time to offset the increased lift and not upset the CG/Drag balance.
@@markp5726 They'd basically be slats and flaps at that point. What youre describing is exactly how aerospace engineers decided to do it on large planes.
@@GS-qw9cc He sadly passed away in a single vehicle motorcycle accident. His father has a video on his channel: ruclips.net/video/UUtTm9be07c/видео.html
I use to love making aircraft from cardboard when I was much younger and tinkering with wing, flaps, shape etc. to get them to fly better and for longer. I used to use the little blue plastic propellers from the 'Flying Gliders' Styrofoam plane kits for propulsion. The kits would cost only a euro and I got endless fun out of making ever more ridiculous designs. Just found your channel, very interesting thanks for sharing!
Really cool build! I think it could be intresting to try this concept for an ekranoplan. They already utilize the ground effect to generate more lift and you could probably make it fly even slower in that configuration.
this looks like it would be super fun to make a ground effect plane with wings similar to this and see what you can get away with like how slow or how steep and maybe how much/little throttle/thrust from the propellers you actually need to keep it up.
Really great engineering. Opens all sorts of options for tweeking. Extending the top wing length by 50% would be interesting to see if it was more stable. Even so this would make a very silent drone.
Could you make some tutorial videos, like on how to solder, 3d model, or basic RC stuff? Always wanted to learn but your videos have made me want to make my own RC stuff!
i think he already has some videos on the basics, however they are really old now, still relevant but not as good filming as his new vids. also sam shepard did a video on the basics of main rc components so you should check that out too
this might have been said already: the thrust force should be located lower to avoid that forward pitch moment on thrust, and this would likely also stabilize it somewhat upon roll
Or angle the motors up. The axle of the motor, if virtully lengthened, should run exactly through the CG of the airplane (not the CG of the wing!) minus 3 degrees, to counter any pitch effects on throttle. If he lowers the motors on this airplane, the props will hit the ground. So either angle the motors or put a landing gear on it and lower the motors.
You should try making a plane you pump up. AKA small backpack plane, you hike into the woods, then you pump it up with a bike pump and it's now a large plane. Fly it for a while, then when done deflate it and put it back into a backpack.
If I recall, there are recipes available online for the smoke used in old school wind-tunnels, and with a good sized shop fan attached to a box with acrylic or fiberglass windows, creating the smoke lines through a few holes in a metal box is actually quite simple. Just remember that you're dealing with fire, so keep the box on concrete and obviously outside.
This was a great watch, i learned so much, but I really like the leisurely speed this plane flies at. That front noise camera was a great perspective too!
I love that you do all the experimentation that I don't have time to do but used to way back when the technology was not what it is today. LOL thanks for uploading and I'm glad you got the plane back without climbing a tree.
There are several effects with the slotted flaps. They are actually called "Fowler" flaps Typically 2 to 4 stage (2 to 4 sections) You can have just one. The flap not only rotates, it is pushed back. This combination opens the slot. It also effectively adds wing area, because in the retracted position, the flap sections overlap each other. Pushed back they expose more surface area. air from underneath is forced through the slot due to pressure differential below vs above the wing. This accelerates the air over the flap. It also helps "lock" the airflow over the main wing panel in a near laminar flow. It helps delay stall. Then there's the changed curve to the effective airfoil, taking a high speed airfoil and converting to a low speed, high lift airfoil, when you consider it as having a continuous curve. The majority of affected air is using this curve. It has long been well known that slots of assorted natures can improve low speed flight. But they add a LOT of drag. There's also a weight penalty involved. Everything about an aircraft is a compromise. Trading increased weight to get strength, increased weight to get more power, increased weight to gain range... Wing shapes are trading between lift and drag. Being able to change the shape of the wing in flight means you can have the low drag shape for cruise and the high lift shape to reduce take-off and landing speed.
Wow! VERY impressive for what appears to be essentially a one man show. I lot of startup companies with a small cluster of employees would be hard pressed to keep up with the ingenuity shown here.
Pretty crazy to see how much your build quality has improved over the years implementing technology, tools, and build techniques. Awesome video, Daniel
Very cool! I remember the Germans had a very successful Tri-plane during WWI - The Fokker DR-1 (DR standing for Dreidecker, or 3 wings) was arguably the most famous plane of World War I. This is probably because it was associated with the Red Baron. The Fokker DR-1 was 5.77m long, 2.95m high, and had a wingspan of 7.19m.
When you Mention the elevons not working well with all three wings attached. It looks like the horizontal stab isn't getting enough airflow because all of the air is being shot down under it.
This feels like a good candidate for 3-d printed wings, since they are each replaceable in that mount. With the flow fly characteristics I hope you continue to develop this or other slow fly designs. :)
@@BlueRadox there's 2 ways of interpreting that comment, it might mean college students don't learn this stuff so they need to or it could mean they do learn it since they need to. I think OP meant the latter.
I'm an old surfboard builder. But when I was a little youngster, my dad and I used to make balsa wood gliders, so I like to see what people are building these days. I Iike the multi wing set-up and the added lift effect. On glassing your wings, I think it's a lot easier to just glass them like a surfboard, with a soft rubber squeegy and fast hardening epoxy. Epoxy that has about 20 to 30 min working time. You can do one side of all the wings in one batch, trim them when they are hard enough not to make the fiberglass frey or tear, so you can slice it clean. That way it fast and easy. Then you put a fill coat on everything, with a 3/4" to 1" (for models) resin brush, so you can sand it flush and smooth.
Daniel, I was super impressed by your design. The presentation was also superb. I had been watching your channel long before ever launching my own just 6 months ago, and you had definitely inspired me in many ways. Keep up the amazing work, and feel free to reach out if you ever need at home manufacturing help. Thats what we are all about. Cheers, Dave
Amazing build! I've always been interested in the use of split airfoil wings. Really cool to see how you used a CNC router for the majority of the build and to make that complex wing geometry! It would be interesting to see how a similar split-wing plane would fly if the entire wing AOA could be pivoted mid-flight, adding a more dynamic flight envelope. Samm Sheperd was another big inspiration to build RC planes for me. Sad to see him go, but great to see his legacy of inspiration continue. RIP
Really interesting. I believe the stalling happens in a little bit different way. The air from under the wing comes around the trailing edge and starts climbing backwards on the upper surface of the wing. The air coming above the wing detatches because there is no vacuum but that backwards creeping air. I got some idea. Make the wing hollow, put a slit at the trailing edge. Add some blower or compressor so the air can be blown out and backwards from the trailing edge. This should stop the air from below the wing coming above. Use the blower at slow speeds, don't need it at high speeds, but it does not hurt, anyway. I have no chance to build a prototype, but it would be interesting to hear if anything like this ever works.
Slow speed fixed wing aircraft looks good while flying. How would this aircraft differ in performance as compared to one with wide wings [as if you stuck these 3 wings tip to tip]?
Given how short these wings are, that would probably just make it a reguar plane. It would likely increase the stall speed, increase the bending moment at the wing roots (increase weight if this requires additional reinforcement), decrease drag signficantly (less induced drag due to the higher aspect ratio; less interference drag; less pressure drag due to decreased area in the direction of flight).
Awesome aeroengineering and construction! I suppose the pitch-down moment when increasing the throttle is because the thrust axes are so far above the averaged lateral axis... seems like that is something that could be overcome with another design. Mount the motors on the middle wing instead of the upper one, maybe.
Couldn't you change the angle that the motors are mounted. I believe RC plane motors are mounted a few deg offset to counteract the propeller rotation causing yaw.
I'm glad to see you make 'special' mention of what you call 'twist' which is really called 'washout'. Washout is critical at conditions nearing stall conditions. At these conditions, portions of the wing nearing the wing tips are still flying. This allows for aileron authority as the stall condition progresses ... you really want that. A more general, yet similar, relationship exists between the mains and tail angle of instances (tail being less than the mains) thus providing pitch authority even as the mains start to stall. Both of these give you a chance to 'wake up' and fly the airplane 'out and away' from disaster.
Hmm, It would be interesting to see if one could make a variable delta wing in this configuration. In a way that it folds/moves into a flatter shape like a normal delta wing after takeoff.
Cool development! Wonderful chilly to watch and listen. What a joy! But what I noticed: a pretty steep angle of the three wings referred to the rear wing. And just by looking at the proportions I could say it was rear heavy. But I was surprised how stable and balanced the flight was. Well done!👍🏼👏🏼👌🏼
Daniel, I truly envy your constancy! I've always been around rc since forever, but lately I could not find time to play around... great videos as always!
Could you build a reconfigurable wing, where each wing can rotate to be more in line with the others and the whole wing assembly rotates to reduce angle of attack?
"All it takes is money" It can be done. The design work takes time (which equates to money... trading $$$ for labor.) It might not be practical due to the structure requirements which might either use prohibitively expensive materials or add excess weight. It takes a lot of strength at the pivot points when you want wing that can rotate in any way.
Dang it flies like a bird! Plus the slower speed does less damage when you run into a tree trunk. I find the characteristics of super slow flight fascinating for some reason. It's under rated in my opinion.
I think it would be absolutely *amazing* for amateurs/children/indoor flight! Imagine if it fly at just about walking speed! You could loiter very well, you could actually fly it indoors in a larg house or definitely a school gym or something. You wouldn't need as much space to fly at low altitude so city kids could fly it at the park, and crash speeds are much lower reducing injury to both people and aircraft! It might be fast, but it's *very* useful! I wonder if inflatable wings could work on this design? It could reduce weight and increase crash resilience.
Very cool Daniel! This may be one of your all time great aviation projects. You have come a long, long way since your first video appearance on FliteTest so many years ago. I remember thinking one day this kid is going to be President of Boeing or something and you are making it happen!
Hopefully not Boeing, that would corrupt his ingenuity and innocence! His own start-up and keeping things innovative without corporate shenanigans affecting decision-making!
I thought about this as well. May i make a suggestion? Try placing the wings in a swept forward and back design. Not too aggressive. The tips should all be close but not touch. Brilliant design and Good luck.
Very nice info on wing aerodynamics efficiency. I’m currently working on a project of my own. But nothing nearly as advanced as this. Nothing relying on any electrical components, just raw materials like cardboard, plastic, balsa wood, and rubber bands.
Your last point is exactly right! To maximise efficiency you want to maximise the lift to drag ratio. Above a certain point it is not worth it to increase lift anymore, because it comes with a larger relative drag increase. This is also why aircraft don't extend their flaps and slats during cruise flight, they only use them when they need more lift for takeoff and landing.
Efficient is a dependable, if you want lift then you cause drag to forward force. So when you have more lift then your plane need more energy to go forward, and vice versa. So in terms of efficient, you need to know motor prop thrust combo and translate that efficient to get exact lift so the drag not holding back the power. Rule of thumb the more airfoil generate lift the more drag they will produce to cruise. So if you targeting to get on the air as long as possible or even hover the plane that might be right term for efficient, but if you want to go from A to B then my explanation above is more efficient
@@ZuNunchaku By definition, the efficiency of an airfoil is the lift-to-drag ratio, it is not debatable. What you are talking about is mission objectives, that is what you are trying to achieve with a certain design. A multi-slotted airfoil is horribly inefficient, but achieves the objective of flying vey slowly.
@@nicholaslau3194 Read carefully the question, he said "the plane is more energy efficient" not the airfoil. There is lot of term of efficient, for example motor-prop-cell efficient, airfoil efficient (as you described), wing area-material wise, etc etc. And my answer is referring to the questions, whereas plane efficient
Around the 10:45 mark you talk about the main gear lifting off first and the aircraft riding along on the nose wheel. I actually saw this exact thing many years ago, 1976 or 77, when Aero Spacelines' Super Guppy took off from Norfolk VA. I was standing at the end of the runway and it was coming right toward me, so seeing it scooting on just the nose gear and rapidly running out of pavement got pretty scary. At that time there was a lot of road construction equipment just off the runway and I had visions of it piling into that, with me standing right next to the fireball. But it barely cleared the obstructions and then flew ponderously off, looking for all the world like a zeppelin since the wings were almost invisible from a distance, leaving that massive fuselage as the main thing I could see. Wish I'd taken photos!
Moving the aft wing up (this is essentially a tandem wing. Between "conventional" and "Canard") will reduce the low speed lift, but might avoid a nasty bad habit of tandems with the wings close to each other.
Engines at the tips could cause some yaw issues. It may be better to mount the engines lower to counter the nose down when throttling issue. The T-tail may make the elevons more effective as there is less downwash from the wings.
@@nicholaslau3194 wouldnt the engine flow going in the wings cause the pitch problem? Maybe puting the engine away from the wings would solve the problem. But yes, lowering the engines would be already a good idea, if you ignore clearance from the ground.
i mean birds already had this down pat as individual feather muscle control and sensory allowing for different flight characteristics based on which muscles they hold tight or loose that's clearly evident in their landings if you can watch such a fast motion and understand it but for takeoffs they'd grip and climb 🪜 through the air only twitching the flaps aka feathers open to slide through the air momentarily bringing wings forward for another down/reverse push stroke
@rctestflight another even better idea for STOL is the following: make it a canard canard and fuse the tail into the slots, e.g. the bigger wings behind, the smaller at front , you know canards are more efficient, and this slotted design will take even more advantage of it
Great Study! Amazing stuff, Eew, Itchy Dust. I love looking back at early flight an it was like Sailing with loose an tight sheets. Must be a modern take on this one day too. Beauty RCTF. brilliant show thanks.
So good to see work being done on this idea. I messed with it myself years ago after noticing the great gliding capabilities of eagles without a high aspect ratio seemed counterintuitive and there must be an idea in it. It depended on multiple winglets or feathers which reduced the inevitable tip vortex that short wings produce.
Search for Al Bowers flying wing for eye opening info on how birds "do it".I am an airline pilot ,ex HGlider and PGlider and i found his theories(based on Prandtl/Horten) and experimental models fascinating.
Daniel, you are absolutely brilliant ... so funny, great design, a plane you can run along with ... visualizing the airflow side by side ... though I was missing some home made music with vocoder lyrics on aerodynamics, as well as one of your hilarious ads ... hopefully next time
Smart projects, perfect video production. Impressive. I would enjoy also a video from the onboard camera flying around and in between trees, with music.
I am an ex Air Force aircraft engineer so no all about theory of flight this is so interesting! I have witnessed the unusual take off attitude of your model with the 'nose down take off' on B52's! Watch them on take offf and they have an almost 'helicopter' strange nose down take off unle any other aircraft I have seen,
Watching this from Feb 16th, 2022. I don't normally watch these so if what I'm about to say sounds a bit strange, oh well. Here goes. In those last scenes of flight when it was on autopilot, it looked like a cartoon character. The color was just right. And its end, totally tragic. You even named the character. Beefy. You might find someone good at cartoon, (AKA Pixar, Plains) illustrations and use Beefy as a staple for your videos. Great job and I learned a lot. Sorry but my mind just see's things like this. 63 and still a child at heart.
What seems to be nice about this multi-part wing design is that it seems to be symmetrical in a design that can fold itself nearly flat for normal use and then unfold for low-speed work. Using flexible membranes and internal shifting "bones" using very light-weight carbon-based materials, you could get this kind of multi-shape wing that gives flight from supersonic to almost like a kite...
That nose-down takeoff definitely showed the magnitude of the crazy pitching moment from this wing. Awesome work man
Ever seen a B52 take off. The rear always gets off the ground first
Do us some new videos about vtol
Not neccesarily, the thrust lines of the engines could be an issue. When they are at the upper level of the aircraft's thrust/drag lines the engines should have up-thrust. Check out some of the amphibious aircraft designs with high mounted engines, they all have up thrust.
Great trial.
Exactly what is a "work man", and how does an awesome "work man" differ from a regular "work man"? Eaten any grandmas lately?
@@vumba1331 I always wondered about the angle especially with sea planes.
The fog machine demonstration was fantastic!!! Seriously appreciate the effort you put in to help us visualize the aerodynamics at play.
This just reminded me that Samm Shepard died a few years ago and made me wonder what we have missed out on. He was one of the best youtube rc channels in my eyes
Yes rip samm he did very cool stuff
Yes Sam is a legend 😇🙏
I started studying engineering thanks to his inspiration
⁵0 to 0
RIP Samm, I loved his channel.
You could probably increase your wing performance if you put the propellers behind the wing. You get super smooth air coming into your super nice wings and then you proceed to make it all swirly and turbulent with the rotors.
Это точно!
I remember seeing Samm's video on this (god rest his soul, that beautiful man he was) and loving it a lot when it came out. Fast forward a few years and I'm a mech E at Gonzaga, and fluids dynamics is about to get into air volumes over planar and curved surfaces, and we talk a little bit about slots and flaps, of course I make the connection to this and bring it up in class, we all watch the video (he apparently showed it to his other classes too), and he goes on a 20 minute discussion about how this wingset works, with the calculus to prove it too. I miss taking fluids, that class was fun as all get out!
How did he die?
@@whitewolf6605 he was driving his motorcycle uphill on road where he used to speed up, but that road do not allow you to see what is at the top because the road surface up there gets suddenly horizontal. Unfortunately a new round about was built up there and he didn't see it in time to break safely, he crashed into it and died three days later....he left behind a loving family, a pilot carreer and a girlfriend that he had just started to date. RIP Sam
Will soon be starting in CU boulder aerospace engineering program, I count Samm Shephard among my inspirations
omg fellow fluids jerma nerd
*Hey, rctestflight - I made one of these with a "V" tail so I could lift, dive and turn with only 2 servos. I also used a Dihedral Wing shape and it was 800% more stable with that Didedral wind keeping the plane flat. Even in high winds it remained stable. Nothing could knock it out of the sky as it automatically found the most stable flight direction even if you wanted it to turn, the design choose STABILITY for its flight direction! I may need a more powerful motor or just wait for days when the wind is under 20 MPH. AMAZING!*
Well, now I want to see just how slow you can make a plane go without stalling out
When i was a kid my friends dad had a biplane, and i remember going for a ride in it. He though it was hilarious that we could fly slower than the traffic on the highway... I think the stall speed on his plane was something like 40 mph... It was pretty cool!
Peter stripol made a walking speed rc plane, was super cool
It's all relative since the lower your weight the lower the lift needed to maintain trim
Anything is possible with enough headwind.
Search vought v-173 flying pancake should be what youre thinking
Throttle causing an aggressive nose-down moment would make for some terrifying go-arounds! Very neat build.
I've been following you for many years, the best flying invention channel out there.
I agree, we all meet here ;)
Awesome design, Daniel! Not only is it really fun, but I also thought it was beautiful as well! I had a few thoughts after watching this video: First, if you do a version 2.0, you might consider giving it a T-tail so that the horizontal stabilizer is in cleaner air. Second, this is probably terrible practice for a number of reasons, but I also have a CNC that I use for machining XPS sometimes, and I have found I can basically skip most of the roughing and be super aggressive on finishing passes with the foam. It saves lots of time, and it doesn't care. Just don't run one of those toolpaths on something stiffer than foam! When you fiberglass a wing, try using waxed mylar against the glass instead of peel-ply, and stick the peel-ply outside of that as a vacuum breather. You will get a shiny surface right out of the bag, and won't have to subject the part to the force of removing the peel-ply. Oh, and your plane is in good company when it comes to using elevons for roll control - the F-14 did too!
Maybe put the wings on a servo to rotate them while landing so you can change the angle of attack? They may need to move rearwards at the same time to offset the increased lift and not upset the CG/Drag balance.
Yeah, having the bottom 2 wings an a switch to level them out would be sick.
Wouldn't that have to be forward, given it's already tipping forward when accelerating...?
I was actually thinking, add a servo and linkage to collapse the lower two wings into the top one. The linkage would be a pain to calculate though...
this is staring to sound like some kerbal spaceprogram level engineering now hahah
@@markp5726 They'd basically be slats and flaps at that point. What youre describing is exactly how aerospace engineers decided to do it on large planes.
Stunning job! and thank you to use the metric notation alongside the imperial one!
99% of the international viewers will be happy!
Rest In Peace Samm. I hope you're still up to your crazy antics, wherever you are
What happened?
@@GS-qw9cc He sadly passed away in a single vehicle motorcycle accident. His father has a video on his channel: ruclips.net/video/UUtTm9be07c/видео.html
Yah man I thought the same thing when he mentioned his name. Gone so young. RIP Sam🙏
Fly high Sam, forever
@@Guffy1990 my heart sunk when I saw his father in front of the camera
I use to love making aircraft from cardboard when I was much younger and tinkering with wing, flaps, shape etc. to get them to fly better and for longer. I used to use the little blue plastic propellers from the 'Flying Gliders' Styrofoam plane kits for propulsion. The kits would cost only a euro and I got endless fun out of making ever more ridiculous designs. Just found your channel, very interesting thanks for sharing!
Would love to see an ultralight version. Seeing how slow you can get the stall speed would be very interesting
Really cool build! I think it could be intresting to try this concept for an ekranoplan. They already utilize the ground effect to generate more lift and you could probably make it fly even slower in that configuration.
Try peel-ply for hinges, it's lighter, cheaper and easier to work with than kevlar. Just gotta be more careful when cutting to free up the join.
THis whole video blew my mind... who would have thought - CNC plane, autopilot... incredible!
this looks like it would be super fun to make a ground effect plane with wings similar to this and see what you can get away with like how slow or how steep and maybe how much/little throttle/thrust from the propellers you actually need to keep it up.
Really great engineering. Opens all sorts of options for tweeking. Extending the top wing length by 50% would be interesting to see if it was more stable.
Even so this would make a very silent drone.
Could you make some tutorial videos, like on how to solder, 3d model, or basic RC stuff? Always wanted to learn but your videos have made me want to make my own RC stuff!
there's a ton of that on the older flitetest youtube videos. have a search. there's even a interview of guys on their stuff back in the day.
i think he already has some videos on the basics, however they are really old now, still relevant but not as good filming as his new vids. also sam shepard did a video on the basics of main rc components so you should check that out too
Yup we need more there can always not be enough of knowledge
this might have been said already: the thrust force should be located lower to avoid that forward pitch moment on thrust, and this would likely also stabilize it somewhat upon roll
Or angle the motors up. The axle of the motor, if virtully lengthened, should run exactly through the CG of the airplane (not the CG of the wing!) minus 3 degrees, to counter any pitch effects on throttle. If he lowers the motors on this airplane, the props will hit the ground. So either angle the motors or put a landing gear on it and lower the motors.
You should try making a plane you pump up. AKA small backpack plane, you hike into the woods, then you pump it up with a bike pump and it's now a large plane. Fly it for a while, then when done deflate it and put it back into a backpack.
If I recall, there are recipes available online for the smoke used in old school wind-tunnels, and with a good sized shop fan attached to a box with acrylic or fiberglass windows, creating the smoke lines through a few holes in a metal box is actually quite simple. Just remember that you're dealing with fire, so keep the box on concrete and obviously outside.
Rip Samm, dude made such good videos.
I was about to say, and I missed this in the rctestflight video, I'm wondering if he knows that Samm passed away. Rip Samm.
His legacy lives on in his videos 🙏
@@MarinusMakesStuff he knows for sure. I think
Wait this guy died?
@@Lotek117 Samm shepherd, not rctest.
Here's a serious compliment. One of the best videos I've seen on YT. (of course I'm a pilot)
This was a great watch, i learned so much, but I really like the leisurely speed this plane flies at. That front noise camera was a great perspective too!
Humanity is involuting... losing cognitive abilities. This video is the evidence.
Absolutely, that was a wonderful perspective.
I love that you do all the experimentation that I don't have time to do but used to way back when the technology was not what it is today. LOL thanks for uploading and I'm glad you got the plane back without climbing a tree.
I always wonder about the slotted flaps when I took a flight.
There are several effects with the slotted flaps.
They are actually called "Fowler" flaps Typically 2 to 4 stage (2 to 4 sections) You can have just one.
The flap not only rotates, it is pushed back. This combination opens the slot. It also effectively adds wing area, because in the retracted position, the flap sections overlap each other. Pushed back they expose more surface area.
air from underneath is forced through the slot due to pressure differential below vs above the wing. This accelerates the air over the flap. It also helps "lock" the airflow over the main wing panel in a near laminar flow. It helps delay stall.
Then there's the changed curve to the effective airfoil, taking a high speed airfoil and converting to a low speed, high lift airfoil, when you consider it as having a continuous curve. The majority of affected air is using this curve.
It has long been well known that slots of assorted natures can improve low speed flight. But they add a LOT of drag. There's also a weight penalty involved.
Everything about an aircraft is a compromise. Trading increased weight to get strength, increased weight to get more power, increased weight to gain range... Wing shapes are trading between lift and drag.
Being able to change the shape of the wing in flight means you can have the low drag shape for cruise and the high lift shape to reduce take-off and landing speed.
Wow! VERY impressive for what appears to be essentially a one man show. I lot of startup companies with a small cluster of employees would be hard pressed to keep up with the ingenuity shown here.
Pretty crazy to see how much your build quality has improved over the years implementing technology, tools, and build techniques.
Awesome video, Daniel
I love the view of the forward mounted camera looking back.
I appreciate the Samm Sheperd credit. Really excellent video.
What a legend, rip Sam
Very cool! I remember the Germans had a very successful Tri-plane during WWI - The Fokker DR-1 (DR standing for Dreidecker, or 3 wings) was arguably the most famous plane of World War I. This is probably because it was associated with the Red Baron. The Fokker DR-1 was 5.77m long, 2.95m high, and had a wingspan of 7.19m.
When you Mention the elevons not working well with all three wings attached. It looks like the horizontal stab isn't getting enough airflow because all of the air is being shot down under it.
neets a t tail. or 3 surface config with canards
This feels like a good candidate for 3-d printed wings, since they are each replaceable in that mount. With the flow fly characteristics I hope you continue to develop this or other slow fly designs. :)
Thanks for demonstrating what aero engineers at the college level need to learn.
Are you saying they currently don't learn this? Because I'm an aero engineer at uni and we definitely did learn this stuff lol. Brilliant video though
@@BlueRadox there's 2 ways of interpreting that comment, it might mean college students don't learn this stuff so they need to or it could mean they do learn it since they need to. I think OP meant the latter.
I'm an old surfboard builder. But when I was a little youngster, my dad and I used to make balsa wood gliders, so I like to see what people are building these days. I Iike the multi wing set-up and the added lift effect. On glassing your wings, I think it's a lot easier to just glass them like a surfboard, with a soft rubber squeegy and fast hardening epoxy. Epoxy that has about 20 to 30 min working time. You can do one side of all the wings in one batch, trim them when they are hard enough not to make the fiberglass frey or tear, so you can slice it clean. That way it fast and easy. Then you put a fill coat on everything, with a 3/4" to 1" (for models) resin brush, so you can sand it flush and smooth.
Daniel, I was super impressed by your design. The presentation was also superb. I had been watching your channel long before ever launching my own just 6 months ago, and you had definitely inspired me in many ways. Keep up the amazing work, and feel free to reach out if you ever need at home manufacturing help. Thats what we are all about. Cheers, Dave
Amazing build! I've always been interested in the use of split airfoil wings. Really cool to see how you used a CNC router for the majority of the build and to make that complex wing geometry! It would be interesting to see how a similar split-wing plane would fly if the entire wing AOA could be pivoted mid-flight, adding a more dynamic flight envelope. Samm Sheperd was another big inspiration to build RC planes for me. Sad to see him go, but great to see his legacy of inspiration continue. RIP
That aero testing at the end was amazing, I would love to see more details of that!
Really interesting. I believe the stalling happens in a little bit different way. The air from under the wing comes around the trailing edge and starts climbing backwards on the upper surface of the wing. The air coming above the wing detatches because there is no vacuum but that backwards creeping air.
I got some idea. Make the wing hollow, put a slit at the trailing edge. Add some blower or compressor so the air can be blown out and backwards from the trailing edge. This should stop the air from below the wing coming above. Use the blower at slow speeds, don't need it at high speeds, but it does not hurt, anyway.
I have no chance to build a prototype, but it would be interesting to hear if anything like this ever works.
impressive how you can basically make everything fly pretty well :)
It is neat to revisit concepts from the two decades before WWII.
Beautiful work.
Slow speed fixed wing aircraft looks good while flying. How would this aircraft differ in performance as compared to one with wide wings [as if you stuck these 3 wings tip to tip]?
My guess is that, as the "slatted" effect reduces stall speed it would, out of necessity, have to fly faster.
Given how short these wings are, that would probably just make it a reguar plane. It would likely increase the stall speed, increase the bending moment at the wing roots (increase weight if this requires additional reinforcement), decrease drag signficantly (less induced drag due to the higher aspect ratio; less interference drag; less pressure drag due to decreased area in the direction of flight).
@@qayray I agree. That's a short and sweet assessment.
@@veloxsouth that aerospace degree of mine has to be good for something! Even if its just commenting on RUclips videos 😂
Need to control “speed” with elevators instead of throttle, the pitch down is caused by CP moved rear as lift increases with constant AOA
Awesome aeroengineering and construction! I suppose the pitch-down moment when increasing the throttle is because the thrust axes are so far above the averaged lateral axis... seems like that is something that could be overcome with another design. Mount the motors on the middle wing instead of the upper one, maybe.
Couldn't you change the angle that the motors are mounted. I believe RC plane motors are mounted a few deg offset to counteract the propeller rotation causing yaw.
It is also probably due to the propeller wash increasing the lift on the wing, and hence the pitching moment.
16.00 look at those control arms bend. great to see people that go to so much effort to experiment and don't give up like i do
That’s an awesome looking plane!
I'm glad to see you make 'special' mention of what you call 'twist' which is really called 'washout'. Washout is critical at conditions nearing stall conditions. At these conditions, portions of the wing nearing the wing tips are still flying. This allows for aileron authority as the stall condition progresses ... you really want that. A more general, yet similar, relationship exists between the mains and tail angle of instances (tail being less than the mains) thus providing pitch authority even as the mains start to stall. Both of these give you a chance to 'wake up' and fly the airplane 'out and away' from disaster.
Hmm, It would be interesting to see if one could make a variable delta wing in this configuration. In a way that it folds/moves into a flatter shape like a normal delta wing after takeoff.
It's slotted flaps, but the whole wing is flaps lol. Sounds like fun
Look up Scrappy Bush Plane a guy did basically that.
Loved the aerodynamics explanation at the beginning! I learned something new off the bat!
I love how slow it looks, it looks like impossible. amazing
Cool development! Wonderful chilly to watch and listen. What a joy! But what I noticed: a pretty steep angle of the three wings referred to the rear wing. And just by looking at the proportions I could say it was rear heavy. But I was surprised how stable and balanced the flight was. Well done!👍🏼👏🏼👌🏼
could you make a multi element 'prop' using these kind of designs?
Crazy idea, but I think its worth trying
Great idea
glad to see a lot of people in this little community remember Samm.
Daniel, I truly envy your constancy! I've always been around rc since forever, but lately I could not find time to play around... great videos as always!
i am not a model plane guy or pilot or engineer but I found this fascinating. Thanks
Could you build a reconfigurable wing, where each wing can rotate to be more in line with the others and the whole wing assembly rotates to reduce angle of attack?
"All it takes is money"
It can be done.
The design work takes time (which equates to money... trading $$$ for labor.)
It might not be practical due to the structure requirements which might either use prohibitively expensive materials or add excess weight. It takes a lot of strength at the pivot points when you want wing that can rotate in any way.
I forgot about your channel. Glad it popped up in my feed. Always love to see your new projects!
Dang it flies like a bird! Plus the slower speed does less damage when you run into a tree trunk. I find the characteristics of super slow flight fascinating for some reason. It's under rated in my opinion.
I think it would be absolutely *amazing* for amateurs/children/indoor flight! Imagine if it fly at just about walking speed! You could loiter very well, you could actually fly it indoors in a larg house or definitely a school gym or something. You wouldn't need as much space to fly at low altitude so city kids could fly it at the park, and crash speeds are much lower reducing injury to both people and aircraft!
It might be fast, but it's *very* useful! I wonder if inflatable wings could work on this design? It could reduce weight and increase crash resilience.
Man, this is so cool, I really love the front camera view. Overall it's a great piece of work, very inspiring.
Very cool Daniel! This may be one of your all time great aviation projects. You have come a long, long way since your first video appearance on FliteTest so many years ago. I remember thinking one day this kid is going to be President of Boeing or something and you are making it happen!
Hopefully not Boeing, that would corrupt his ingenuity and innocence! His own start-up and keeping things innovative without corporate shenanigans affecting decision-making!
This sort of thing would make a really good beginner plane, nicely done.
That was pretty awesome! Have you considered connecting the wingtips for more rigidity?
There is enough rigidity, except when it crashes.
Bravo ! Vous re découvrez le principe des plumes rémiges des oiseaux.
Well done ! You rediscover the principle of the remige feathers of birds.
The concept is great and I'm sure with enough R&D it could make for an efficient and stable light aircraft.
Then yet again, the Simpsons predict the future...
If that Simpson's prediction comes true in full, I'm no longer getting on a plane.
I thought about this as well. May i make a suggestion? Try placing the wings in a swept forward and back design. Not too aggressive. The tips should all be close but not touch. Brilliant design and Good luck.
This feels like we're bringing back multi-winged planes from the early 1900's, but with extra science.
I think so too, there's a reason we abandoned the biplane as the dominant type. But this looks awesome, so I don't mind. :)
Very nice info on wing aerodynamics efficiency. I’m currently working on a project of my own. But nothing nearly as advanced as this. Nothing relying on any electrical components, just raw materials like cardboard, plastic, balsa wood, and rubber bands.
Does more lift mean that the plane is more energy efficient because you can fly it slower? If so, does the increased drag negate this benefit?
Your last point is exactly right! To maximise efficiency you want to maximise the lift to drag ratio. Above a certain point it is not worth it to increase lift anymore, because it comes with a larger relative drag increase. This is also why aircraft don't extend their flaps and slats during cruise flight, they only use them when they need more lift for takeoff and landing.
@@kianheus2487 that's very interesting, thanks!
Efficient is a dependable, if you want lift then you cause drag to forward force. So when you have more lift then your plane need more energy to go forward, and vice versa. So in terms of efficient, you need to know motor prop thrust combo and translate that efficient to get exact lift so the drag not holding back the power. Rule of thumb the more airfoil generate lift the more drag they will produce to cruise. So if you targeting to get on the air as long as possible or even hover the plane that might be right term for efficient, but if you want to go from A to B then my explanation above is more efficient
@@ZuNunchaku By definition, the efficiency of an airfoil is the lift-to-drag ratio, it is not debatable. What you are talking about is mission objectives, that is what you are trying to achieve with a certain design. A multi-slotted airfoil is horribly inefficient, but achieves the objective of flying vey slowly.
@@nicholaslau3194 Read carefully the question, he said "the plane is more energy efficient" not the airfoil.
There is lot of term of efficient, for example motor-prop-cell efficient, airfoil efficient (as you described), wing area-material wise, etc etc.
And my answer is referring to the questions, whereas plane efficient
2:22 RIP Samm... damn its been over 3 years already
Very well made video. The camera shots while flying are incredible.
LOL I just watched a bunch of your old narrated fpv videos and then you upload a new one xD
I know nothing about the subject and I was mesmerized. Wow great video!!!!!
Be interesting to see how this 3 wing setup would work with ground effect on the Ekranoplan
Although lift increases, both profile and skin friction drag increases as well, so more power is required. Very Well done man ... awesome video.
10:10 "I have the altitude set to two meters"
Wow, you must be pretty short, then :P
Around the 10:45 mark you talk about the main gear lifting off first and the aircraft riding along on the nose wheel. I actually saw this exact thing many years ago, 1976 or 77, when Aero Spacelines' Super Guppy took off from Norfolk VA. I was standing at the end of the runway and it was coming right toward me, so seeing it scooting on just the nose gear and rapidly running out of pavement got pretty scary. At that time there was a lot of road construction equipment just off the runway and I had visions of it piling into that, with me standing right next to the fireball. But it barely cleared the obstructions and then flew ponderously off, looking for all the world like a zeppelin since the wings were almost invisible from a distance, leaving that massive fuselage as the main thing I could see. Wish I'd taken photos!
I would like to see this plane with the engines in the tips of the wings, and a mighty T tail. I think that would change things no?
Moving the aft wing up (this is essentially a tandem wing. Between "conventional" and "Canard") will reduce the low speed lift, but might avoid a nasty bad habit of tandems with the wings close to each other.
Engines at the tips could cause some yaw issues. It may be better to mount the engines lower to counter the nose down when throttling issue. The T-tail may make the elevons more effective as there is less downwash from the wings.
@@nicholaslau3194 wouldnt the engine flow going in the wings cause the pitch problem? Maybe puting the engine away from the wings would solve the problem. But yes, lowering the engines would be already a good idea, if you ignore clearance from the ground.
Daniel, this video, commentary, test equipment and work is amazing. Very informative & well, just awesome all round. Thanks for sharing.
i mean birds already had this down pat as individual feather muscle control and sensory allowing for different flight characteristics based on which muscles they hold tight or loose that's clearly evident in their landings if you can watch such a fast motion and understand it but for takeoffs they'd grip and climb 🪜 through the air only twitching the flaps aka feathers open to slide through the air momentarily bringing wings forward for another down/reverse push stroke
i had a fucking stroke reading this.
@rctestflight another even better idea for STOL is the following: make it a canard canard and fuse the tail into the slots, e.g. the bigger wings behind, the smaller at front , you know canards are more efficient, and this slotted design will take even more advantage of it
Great Study!
Amazing stuff, Eew, Itchy Dust.
I love looking back at early flight an it was like Sailing with loose an tight sheets. Must be a modern take on this one day too.
Beauty RCTF. brilliant show thanks.
So good to see work being done on this idea. I messed with it myself years ago after noticing the great gliding capabilities of eagles without a high aspect ratio seemed counterintuitive and there must be an idea in it. It depended on multiple winglets or feathers which reduced the inevitable tip vortex that short wings produce.
Search for Al Bowers flying wing for eye opening info on how birds "do it".I am an airline pilot ,ex HGlider and PGlider and i found his theories(based on Prandtl/Horten) and experimental models fascinating.
Excellent video. I've been interested in this wing configuration for decades.
I'm sure Handley-Page would be happy to see his work still inspiring people today.
Daniel, you are absolutely brilliant ... so funny, great design, a plane you can run along with ... visualizing the airflow side by side ... though I was missing some home made music with vocoder lyrics on aerodynamics, as well as one of your hilarious ads ... hopefully next time
Very Impressive proof of concept prototype. Thank you for sharing this.
Smart projects, perfect video production. Impressive. I would enjoy also a video from the onboard camera flying around and in between trees, with music.
Awesome project, great job playing around with multi wing design!
I am an ex Air Force aircraft engineer so no all about theory of flight this is so interesting! I have witnessed the unusual take off attitude of your model with the 'nose down take off' on B52's! Watch them on take offf and they have an almost 'helicopter' strange nose down take off unle any other aircraft I have seen,
Watching this from Feb 16th, 2022. I don't normally watch these so if what I'm about to say sounds a bit strange, oh well. Here goes. In those last scenes of flight when it was on autopilot, it looked like a cartoon character. The color was just right. And its end, totally tragic. You even named the character. Beefy. You might find someone good at cartoon, (AKA Pixar, Plains) illustrations and use Beefy as a staple for your videos. Great job and I learned a lot. Sorry but my mind just see's things like this. 63 and still a child at heart.
kool plane. you make look into the B-52s "Tail-Up" takeoffs under certain conditions for your answer.........
Indoor flyers will love this concept!
What seems to be nice about this multi-part wing design is that it seems to be symmetrical in a design that can fold itself nearly flat for normal use and then unfold for low-speed work. Using flexible membranes and internal shifting "bones" using very light-weight carbon-based materials, you could get this kind of multi-shape wing that gives flight from supersonic to almost like a kite...
I had no idea how accessible all that autopilot technology is! Unreal!
I never thought that airfoil can be triple or multiple complex, wonderful idea!
Randomly came across this video. Very happy I did. Thank you
There is more technology in this experiment than in in my whole car lol!!! Very well done, compliments!