Ornithopter Flying Machine Part #2

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I really want to do more flying projects. An ornithopter is something that flies by flapping its wings. There are various off the shelf kits available but I wanted to start from scratch and work my way through all of the development. Check out the previous video to see where I failed: • Building an Ornithopte...
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XROBOTS
Former toy designer, current KZbin maker and general robotics, electrical and mechanical engineer, I’m a fan of doing it yourself and innovation by trial and error. My channel is where I share some of my useful and not-so-useful inventions, designs and maker advice. Iron Man is my go-to cosplay, and 3D printing can solve most issues - broken bolts, missing parts, world hunger, you name it.
XRobots is the community around my content where you can get in touch, share tips and advice, and more build FAQs, schematics and designs are also available.

[@integza]

Ive been in love with the idea of 3d printing an ornithopter for a while now, hoping you figure it out so I can copy it

[@g60force]

SAME!

[@SemiCollin]

Same, I have a really small 3D printer though so it sometimes is a pain

[@stocchinet]

I don't see any jet engine in the word ornithopter

[@lucachacha71]

@@stocchinet or maybe a Wankel engine

[@P8FPV]

Dito 😁😉

[@RegisMichelLeclerc]

The problem is still exactly the same as what I pointed out last time: if you're just flapping up-down, you oppose the exact same force when you're flapping up and when you're flapping down, therefore the best you can expect is the same as when you're hovering. Most ornithopters add a mechanism to fold the wing on the upwards movement and extend it on the downward movement. This can be achieved with just a hinge in the middle of the arm, there is no need for extra control surface. A lot of ornithopters implement a forward-backward movement as well to increase the forward thrust, in a movement very similar to swimming butterfly-style. Cheers!

[@baldhat2498]

this needs more likes so he sees it

[@galaxyboots]

thing is I have a sean kinkade ornithopter which flys just by pushing up and down and I've had several toy ornithopters which fly exactly in this way with a simple cam that flaps a piece of canvas up & down. They work great and do fly very well. I think as long as you have an overall positive angle of attack - usually with a servo controlled horizontal tail which can also twist slightly to the right and left for turns as well as up & down and a forward force provided by the simple flapping cam and flexible fabric, it will fly.

[@ihydf]

Why try something new when you can just optimize your bad design ;) Here's what a working bird drone mechanism looks like kzbin.info/www/bejne/hGrFZWiYh7iffZo

[@JMMC1005]

You're right in that you can gain more efficiency with a more complex wing movement, but simple flapping won't prevent flight. Plenty of model ornithopters work just fine without this. Flapping in an ornithopter is to develop *thrust*, not lift. The up-and-down motion (provided the wing fabric is a little flexible) will push air backwards, generating thrust. The wings can generate lift (even without flapping) provided there is enough airspeed. Plus, any positive angle-of-attack means that some of the thrust will be directly acting as lift, too.

[@jameshughes3014]

I'm sitting here staring at yet another one of my projects that has devolved into a chaotic mess, thinking of giving up. Then James posts this, where he returns to an old project and keeps on trying. It was just the inspiration I needed, at just the right time. Thank you Mr. Bruton

[@Matty.Hill_87]

What are you trying to make? Don't give up dude you will get there

[@jameshughes3014]

@@Matty.Hill_87 a thing that plays music with stepper motors , plus a lucky cat robot drummer. Thanks for the vote of confidence 🙂

[@endthefighting]

Never be afraid to start again from scratch. I find that re-approaching a project I've restarted gives me the insight of previous pitfalls and things picked up along the way.

[@jameshughes3014]

@@endthefighting this is excellent advice. Thank you

[@endthefighting]

@@jameshughes3014 it can also be boiled down to "It's not restarting, it's starting with experience ". I find myself constantly doing this in Fusion 360, when my projects get too convoluted :)

[@FrostCraftedMC]

im conviced that a huge amount of efficiency could be gained by giving the wings an "elbow" joint so that they can change shape on the upswing and avoid drag pushing them back down

[@goodboiadvsp3297]

Just like the real thing 🙂

[@MrMontugar]

Plus, real bird wings allow air to pass between the feathers on the backswing.

[@Morberis]

Yes!!

[@sleepyzero5363]

When the wings flap, they produce lift on the downstroke but don't they also produce downforce on the upstroke? If this is the case, should the two forces be equal and cancel each other out? Therefore, shouldn't the wings be designed so that they are stiff on the downstroke, but become flexible on the upstroke to reduce the amount of downforce produced resulting in a net positive lift?

[@schubutz]

the bird wing forms an airfoil like at a plane. the lift comes from the forward moving and not from the downstroke. you will hardly see a bird taking off straight vertically they almost always need a little runway (forward motion) to produce enough lift. of course hummingbirds are an except here, they have their own physics

[@parthsavyasachi9348]

You are right and this is why the way birds move their wings is bit different. The change the shape such that they avoid downforce.

[@myssba]

You are right .There are no airfoils on the wings. Top/bottom equal. Absurd. Or the up and down movement should also change the form. (sorry google translate)

[@ltjgambrose]

@@schubutz Hummingbirds are to birds as helicopters are to airplanes.

[@schubutz]

@@ltjgambrose exactly

[@Travis7109]

Birds don’t flap up and down. It’s more of a forward, wavy, scooping motion. So maybe a cammed flapping mechanism

[@sjdpfisvrj]

That's actually my main issue with this entire effort. I have a bit the impression James thinks enough flapping up and down makes something fly.

[@these.are.my.things]

Coming from an rc plane background. The immediate pitch up when you throw it means it's tail heavy. Move everything further towards the front maybe a more compact gearbox. Try and get it where it glides smooth and straight after you throw it without the motor on. It should not pitch up or down. Then make minor adjustments from there for it to fly with power. I would suggest moving everything forwards remember even a small amount of weight very far back has a big impact due to its lever action. In flying things balance is more important then anything else. You can fly a flat piece of cardboard if you get the balance correct. Get the cg right and the rest will be easy. Maybe buy a kids chuck glider and experiment with attaching weights to see how it behaves so you can recognise the behaviour in your bird. Keep up the good work I hope you get it going.

[@PKMartin]

That was my immediate reaction: every flight stalls, so it looks like it's either trimmed too high and needs the tail tweaked downwards, or more nose weight.

[@these.are.my.things]

@@PKMartin Yeah from what I can see many of these fly with a lot of up trim. My guess would be cg needs to be very close to the front Wing spar. Not an expert on ornithopters but that would be my hunch.

[@Mike-oz4cv]

I think a big problem with the ornithopter is that the center of lift changes as it flaps its wings.

[@5peciesunkn0wn]

I think he should add a nose to it. A) It'll protect the front bearing/pulley system. B) He can add holes in it to fit weights.

[@AltMarc]

I own a Kinkade ornithopter, the pitch up is normal at start BUT without tail control there is no way to counter act it. Once it fly forward the pitching up gets away.

[@sedon7098]

You could also instead of using a bigger reduction a motor with a Lower kV rating to get less rpm and more torque Like use something around 500-600 kV and you wouldn't have the problem of it running to fast and more torque so no stalling out

[@merseyviking]

I came here to say exactly that.

[@TeamPanicRobotics]

500-600kv motors arnt super common in the size he is using, if you go one or two sizes up you can find them but then you need bigger ESCs and are adding more mass so its a trade off

[@merseyviking]

@@TeamPanicRobotics My quad has 580s in 3508 and I use 30A ESCs. They're not that uncommon, although yes they are physically bigger.

[@christianfilloux]

@@TeamPanicRobotics generaly heli motors are lower KV than plane or multi rotor motors..

[@krupert8355]

Some suggestions. 1: Lowering the front pulley to increase distance between wing so that the pushrods are longer, and installing them further out on the wing spar, this will reduce flex and strain within the mechanical system and help reduce the wing flutter from high motor speed. 2: Lowering weight by bonding the carbon fiber parts directly to each other, eliminating the need for 3D printed parts in certain areas. There are a few ways to do this, but one could be wrapping string around the joint and soaking in CA glue, or presoaking in epoxy/resin. 3: Reducing the size of the battery for shorter flights but with less weight. 4: Changing the motor for a more pancake shaped larger diameter one. You will maintain the same weight of the motor, but it will have a higher torque, lower RPM rating. 5: Use smaller bearings. Ideally you want to use the smallest inner diameter bearings as those will offer the least resistance. An overall smaller bearing also means less weight. High RPM and large diameter thin bearings will have a lot of resistance (due to the small balls rolling on a large diameter inner race), like on your current motor shaft setup. There is no need to worry about strength as just about any ball bearing will outlive most of the parts you attach it to. 6: Adding keys in the 3D print so that parts grab onto each other, requiring less screws, and the screws can be smaller, reducing weight. 7: Using a gear reduction instead of belt drive. While the belts are quieter, a gear reduction would be much more compact and lighter, potentially requiring only 1 or 2 stages for the same reduction as a 3 or 4 stage belt reduction simply due to being able to use gears with more size differences. Other than the weight savings from less stages, a gear drive also has no need for belts which further reduces weight. All that being said, I think your build looks fantastic, and I hope to see it fly by itself. Keep up the good work!

[@Mike-oz4cv]

2.: You only gain something if all the string and glue is lighter than the 3D printed connector. 5.: With 3D printed axles large diameter bearings allow for stronger axles. I don’t think the friction of bearings is a significant problem here. The weight is probably more an issue.

[@krupert8355]

@@Mike-oz4cv You are right, however glue and string is a similar construction method as the carbon fiber itself. He could replace string with a fiberglass cloth thread. It would be much more compact than a 3D build as well so overall I don't think there would be a weight gain over plastic, especially sonsidering 3D printed plastic layer adhesion weakness requiering extra plastic. Bearings can be a significient source of resistance depending on application. Even the type of lubricant will greatly affect performance. The low rpm bearings at the front won't be much of an issue due to the low speed and high torque, however the bearing that the motor is mounted on could be a source of current draw due to the motor's high rpm. The bearing design also requires the inner bearing balls to spin very fast which multiplies any rolling resitance. An example of how lubricant affects things is a fidget spinner. These don't use lubricant which allows the bearing to run freely at high rpm, however the lack of lubricant will cause premature wear if put under a weight load. Conversely a bearing with thick grease will have high rolling resistance, but will be able to support higher pressure loads without wearing out prematurely. Your point about shaft diameter is valid though. I think my main concern is with the motor bearing which could be mounted to a smaller diameter shaft, considering the motor already has a small diameter shaft, and torque forces are also low, basically it's just a question of maintaining centering. Still these are good things to think about, and what you said is valid.

[@CuervoRC]

When an airplane climbs suddenly and stalls, it is usually because of the center of gravity. I think that the center of gravity should go more towards the nose, I am an expert in model airplanes but not in ornithopters, although I guess that the distribution of weights and angles of incidence will be similar.

[@CHUCKLZLORD]

It's "stalling" because the engine is stopping, since it can't handle the load.

[@daddyplankton5855]

@@CHUCKLZLORD an aircrafts wing can stall before the engine itself can't handle the load

[@Cowboyfan-wk6ww]

@@daddyplankton5855 you can see this in flight simulator games like War Thunder for instance.

[@rbog8345]

Hombre mister cuervo tio, mi mentor en el rc, está bien verte por aquí

[@JMMC1005]

You're 100% right. I (and a few others) left comments on the last video about this. If the centre of gravity is not correct, it WILL NOT FLY. Period. It was definitely tail-heavy during the first attempt in this video (as was his last design). It looks a lot better once he moves the battery forward, though.

[@GoblinAlchem]

You should think about aerodynamics. To fly a device heavier than air you need lifting force, something that would push the device upwards. By far your ornithopter is symmetrical relative to the up-down direction: it pushes up and down equally during an equal amount of time, so it cancels out. That's why it travels the same distance regardless of whether the motor is on. Probably you need some kind of articulated wings which would fold when moving up, either driven by the same motor or using a free hinge with limited motion range.

[@Linuxpunk81]

He was told this dozens of times in his last video comments but seems to have completely ignored them 🤷‍♂️

[@JMMC1005]

@@Linuxpunk81 It's because it isn't necessary for flight. Look at simple rubber-band powered ornithopters - they fly just fine, with a symmetrical flap. The flapping is to generate thrust (the loose fabric pushes air backwards). Lift comes from moving forward with a positive angle of attack, just like an aeroplane wing. Complex flapping can be helpful, but it is not necessary for flight.

[@plam600]

No ornithopter expert here, but looking at a group like flite test you will note that every build starts with perfecting the glide. No amount of power can fix a wing that doesn't have a decent glide to start. Might just need a little cog and tail configuring. Looking forward to P3!

[@Skyentific]

Great project! Just one more reduction stage to fly!

[@GunGryphon]

Wide bore bearings are an addiction, once you use them once, they end up everywhere.

[@tiporari]

Great progress! Having flown ornithopters successfully and with failure, the initial launch is difficult even with tail control. Unless you can control the pitch up moment from thrust at launch it won't get enough airspeed to stabilize. A small headwind helps. Unlike a prop or jet which thrusts fairly linearly along the long axis, these produce both forward and upward thrust. The tail is necessary to compensate for the lift and produce forward acceleration. Just like a high wing plane with full flaps, you have to push the nose down with the elevator or it will stall as you climb. You also need to give it a fairly strong forward initial launch as these don't accelerate smoothly or quickly. They can't take off from a dead stop. Hope that makes sense.

[@deefstes]

I'm no aeronautics engineer but I'm trying to work out how these wings would generate any lift. It seems to me that the downstroke pushes the ornithopter up while the upstroke pushes it down again by the same amount. So the net result is no lift and gravity wins. I can understand that it would produce forward thrust, which would be useful for generating lift with the tail but something tells me that it would be much more successful if the wings generated at least some, if not most of the lift. One approach I can think of would be to constrain the trailing edge of the wing such that it can't flex above the plane of the wing but it can flex below. That way the downstroke will present a larger surface area than the upstroke.

[@jamesbruton]

Air comes out of the back and it faces up at the front, as far as I can tell

[@leowoolf1532]

@@jamesbruton Falcons and other big birds fly by spreading their wings fully o when moving them down, and then contracting them a bit when putting them back up so they generate push around less air. Do you think you could accomplish something like that with a one-way hinge and maybe rubber bands to keep it from contracting too much? Just an idea I had.

[@jetzereitsma1276]

@@jamesbruton also, if you look at feathers, they are like a one way valve. allowing the air from top to bottom, but not from bottom to top. Maybe you can implement something like that by using a lose peace of fabric as a valve?

[@MediumPointBallPoint]

@@jamesbruton Maybe you should make this point with more vigor. I think the wings operate more like those of a stingray, creating thrust, and lift comes from the angle of attack of the whole mechanism. That said, perhaps a bench test to maximize thrust first.

[@JMMC1005]

The main point is to generate thrust. The lift comes from the same mechanism as an aeroplane wing: airspeed. An ornithopter should be able to glide without flapping. The flapping is just to act as a substitute for a propeller.

[@Matty.Hill_87]

Your unwillingness to give up on a project just because it didn't work the first time is awesome, looking forward to seeing how this thing evolves

[@jamesbruton]

Thanks, well I have been doing robot dogs for a while too ;-)

[@AndrewLeTourneau-CenterOrbit]

Swarm couldn't have picked a better KZbinr to sponsor! Very cool product.

[@richhandler2621]

Have you done regular rc planes? I think there are some fundamentals to be learned that will help with this project ( : I've learned a lot from your videos! thank you!

[@ArtamisBot]

Hey... sometimes ya gotta run before ya walk

[@woofcaptain8212]

Ngl this is the first sponsor on KZbin I've seen in a while that actually seems cool af

[@mickgibson370]

I am watching James! I want to build an ornithopter! I use to fly control line in 1961. I build a model of jet that would FREE FLIGHT for 5 minutes in a room about 6 m x 6 m 3m in high school out 1 gum paper, Juicy Fruit or Spear Mint. They were the smallest powered planes at the time. And then the motor, A FLY!

[@kiwifrogg]

I have a 2-meter V tail glider, the servos are up front in the fuselage and the tail is controlled with 2 quite thin but not flexible wires running inside the carbon tube with a cap on each end to keep them in place. It can handle very heavy Bungy launches and even a winch launch without the flaperons moving. This would allow you to control the tail without adding tail weight, you may also find that some upward tail input is needed when launching.

[@HaloWolf102]

You can see in the demonstration of the ornithopter, that when the wings go down, it wants to go up. If you observe birds before they land, they will leave their wings up, and their trailing feathers down. This is to basically slow down. If you prevent the flexibility of the wing (maybe more tape in those areas) it will be more stable. Example: Hold out your open hand to the side of you. Do a up and down motion. Now what I want you to do is try and roll your forearm back and forth without moving your hand. The motion you are doing is key to stopping, or gaining altitude, in combination with how many flaps per second. In his model, and in many ornithopters, this is not implemented. No one can imagine their ornithopter to land like a bird, so they eliminate that variable and they keep trying with their stiff model. I don't study bats, or birds, so I could be wrong. If you don't want to implement this mechanism, you can go with the bat model, which people already do, and I think it would be better suited for your project here. In robotics, the more you put weight on a joint that is perpendicular to it's mass, it has a hard time moving. So manufactures put the motors closer to the center of mass, and use strings and cables to manipulate appendages. *It's a good idea to make fingers that are restricted in certain axis, and can change the restricted motion of one axis to a motor.* In any case, I am eagerly awaiting your next prototype, hope this helps.

[@Shokman08]

Just a trick for the motor control. You can change the radio control output so you can actually use the radio comfortably. You are using a flysky, check the dual rate and throttle curve configurations. Hope it is useful. Good luck!

[@jarekmace1536]

for a good design idea, look at the ornithopter released by Wowee toys about 15 years ago. Modeled on a dragonfly, it was an RC with two sets of wings for lift, a tail rotor for steering, and a small LiPO battery, all mounted in a Styrofoam body. The wingspan and body were both around 12" long and the whole thing weighed less than a C-cell battery.

[@SteveRowe]

When at first you don't succeed, keep moving forward. Good luck with your design, Steve.

[@vectorentertainment1733]

I love how you design your projects to be assembled so easily

[@Infi3696]

Once when I was young, me and my cousin built something like this with sticks, plastic bag, motor we didn't have any 3d printer. We were working on it until our grandma thought it was rubbish and put it in the bin 😐.

[@Pyromancers]

For super strong but crazy lightweight wing material (much lighter than ripstop nylon) look up cuben fiber. It's used in racing sails and outdoor gear. Amazing stuff. Like tissue paper made from UHMWPE fibers laminated with Mylar. You won't tear it but it'll shave off some weight. Just make sure to get the really light tissue paper like stuff as there are various thicknesses. There are 3m adhesive tapes that can stick it.

[@ojkolsrud1]

Regarding finding the right speed - if you enter the endpoints or mixer settings on the radio, you can set what the maximum PWM to the receiver should be. That way, you can move the gimbal all the way to the top if you like, and have that be the actual top speed of the motor that you want

[@illusivec]

Remember gents, a noseheavy aircraft flies poorly. A tailheavy aircraft flies once.

[@griptopia]

I design for a living, You, Integza, Tom stanton, Peter Sripol , you all have such different but brilliant approaches to things. Thank you for inspiring me and helping me shift my designers block! I design lighting and door handles etc.. Watching others push their creativity in fun ways is just my kryptonite when i'm supposed to be doing real work :)) xx AWESOME STUFF JAMES!

[@scrappypirate2268]

For the wings. If you lay a slightly longer length of rod along the top of the finger splines and attach the ends to the shorter splines you will make them into a scoop. This will add lift

[@NeoIsrafil]

Ooh, I LOOOOOVE ornithopters! Wonderful aircraft! It looks like you need a TOUCH more rigidity in the main wing spar since its stalling when you have it basically at the right speed for flight. Youre so close, gear reduction, a little more rigid main spars, and you may as well build in the tail control cuz you're basically there.

[@marks47]

9:10 never thought I'd hear the word "gnarly" again.

[@Pulsarstunes]

The key thing here is the location of the center of lift, versus the location of the center of gravity. In most model and large airplanes, the center of lift is located around 1/4th of the chord of the wing. Try to position the battery so that the center of gravity of the whole machine is close to the 1/4th point of the wing chord (measured from the front of the wing).

[@DasIllu]

Quick suggestion: If you look at slomo footage of birds in flight you'll notice that the upwards and downwards motion of the wings are not symetrical. If you look at the wingtips you notice that they tilt upwards during the upwards stroke. Thus the wing meets less air resistance than on the down stroke. This is how a bird generates net lift. Imagine sitting in a rowing boat, moving the paddles back and forth but never lifting them out of the water. You wouldn't go anywhere. If wou would turn the paddles ~90° on the back stroke and return to 0° on the forward stroke, you get a net force that pushes you forward. Now a bird does not have the luxuray of being able to "lift it's wing out of the air" so the only option is to tilt. Doesn't have to be 90° though. Another added benefit is reducing the drag on the up stroke, thus reducing the load on the motor, saving heaps of energy. Oops, not that "quick" of a suggestion ;-)

[@KristopherDick]

Your wing spars should be moving through an ellipse such that the down stroke transitions into the back stroke which transitions into the upstroke which traditions into the forward stroke. This will increase wing area on the down stroke and decrease wing area on the upstroke, resulting in best positive down stroke force. The motion of a birds wing is actually much more complex than this, but your current design will only ever fly less than it's passive glide because every time the wind go up, the body gets pushed down and you're creating a great deal of turbulence. You probably also want to use fiberglass rods for wings so they'll flex more, allowing the wing to motion to be exaggerated.

[@biscuitsalive]

Looking at real birds of that size generally have a slower flap speed but the wings move further. So my suggestion would be to change the leverage on the wings so they travel further and move more air, but flap slower. (So gear it down more to give motor more torque too.)

[@ElectraFlarefire]

The fear face about 7:41 is really good.. :) Scary Ornithopter!

[@bellafemedia]

I love that you show all the setbacks and adjustments. It's very encouraging in a real-world way.

[@infantrypaladin]

Dear James, Consider utilizing the tail before your full rebuild. I bet you could motivate the tail to compensate for slow flight, take off and potentially hovering.

[@jman44]

Bigger wing span means lower flap rate. Use 2 servos to control the tail for yaw and pitch. Weight is the enemy of Ornithopters, a smaller battery is better. On a large ornithopter like yours, you may want to make a glide lock so when you reach altitude you can just glide/thermal around. I have an original Kinkade Ornithopter, I suggest you look at how they are built and operate so yours can be successful too. Best of luck!

[@NickRoosen]

To help with motor speed consistency, you could try reducing the Throttle Channel END POINT (pg. 22 in the FlySky manual). That way, you could push the throttle stick all the way up each time, and adjust the max output in software as needed.

[@dimman77]

I had a toy ornithopter as a kid. I remember there was an elastic band than ran from the head to the tail that you would wind up. Wings were like yours except sheet plastic. I remember it flying. I'm guessing the flapping was just a simple offset crankshaft/Conrod from the rotation of the elastic to vertical reciprocal motion. But being a kid and it being ages ago it could have just flapped while you threw it and no real lift...

[@poshhippie6446]

Great video, it seems like the range of motion of the wings is much smaller than other ornithopters of the same size. Large birds like eagles have almost 180° of motion while things like dragonflies can get away with less due to their much smaller mass

[@Spinningininfinity]

First make a glider, that will give you the weight ratios, then add the flapping mechanism to the wings. An aircraft needs forward momentum in order to stabilise, birds don't need this as they have very fine motor abilities which trim their wings and there feathers create laminar flow which also stabilisers the lift. Love your videos, congratulations on your 1,000,000🥳

[@mikosoft]

Me: Trying to minimize my use of plastics James: Builds a huge robot made of plastic every week

[@jameshughes3014]

most 3d printed stuff is made of plastic that can, technically, biodegrade. I'm working on coming up with a reliable, easy way to do that.

[@mikosoft]

@@jameshughes3014 that's good thinking. My comment was kinda meant to be light hearted but it probably didn't come through that way though

[@hultaelit]

I don't see how you are to achieve any meaningful lift from the flapping of the wings when they move in a straight line. Plot the wingtips position on a graph, one axis is fixed and the other goes up and down. As the wings spend half their time going up and half their time going down they will cancel each other out, half the time pushing the plane down and half the time lifting it. A sinewave averages out to 0, as does the lift of this plane. The better attempts is likely due to it acting as a better glider due to the position of the wings at launch. There is not even time for them to flap twice on any attempt, they crash before that. So how is the flapping motion supposed to contribute significant lift?

[@narxic]

I definitely don't have all the answers to the questions you've posed but a single axis flap seems to work on other ornithopter builds he showed in the video. I think it has to do with the trailing end of the fabric wing that creates the forward motion. Here is an example of his build reduced to the most simple form kzbin.info/www/bejne/mXS2Y2p8nrqHiaM

[@crackedemerald4930]

@@narxic it looks like it's just "snaking" through the air, creating thrust, pushing the craft forward, like a snake or an eel.

[@andzerb]

@@crackedemerald4930 yes, I was super into ornithopters for a while, the flapping creates thrust and the forward velocity in air creates lift on the wings.

[@crackedemerald4930]

@@andzerb that's exactly what my hypothesis was

[@k2343ksks3]

3rd stage gears are going to add more weight and in the wrong place.. redesign the two stage to maximum allowed by the belts and whatever weight that adds will be towards the front.. remember when making paper airplanes.. a paper clip is put on the front.. the weight at the front allows the noise to dive and thats how it gets a lift! keep up the good work, cheers

[@Francois_Dupont]

birds use the stiffness of their wing feather to push the air with the feather tips. the front of the wings is also shaped like a plane aerofoil. (or the other way around if you like)

[@sausagesmcgee7079]

how does this guy do so much work! unbelievable! amazing!

[@bpark10001]

The load on motor gets high as the wing flaps down & reduces when flapping up. I would add a spring that exerts 1/2 down force on the wing, so the load on the motor is equal when cruising.

[@lio1234234]

I think the issue is with your motor not being able to run at low speeds. Either brushed or a sensored motor and ESC combo would be a good alternative. The sensored combo would also give you a lot more control over the motor

[@justintyler4814]

I think if you hollow out every part way more and for the front rods and add joints with Maybe a wire to keep it tight you can achieve a more natural lift inducing wing structure. Like if you hollow the front rods, snap em in certain places, keep em tight and together with a cord of some sort and allow it to be a pumping arcing flap instead of a flat one Birds have hollow Bones and jointy movements. The bigger you go the more so.

[@BenRyherd]

You might dial down your dual rates or end points on your throttle. Just run down your throttle up endpoint to wherever the max speed that the wings behave happily at, then you can just go full throttle and know it'll be the right speed.

[@tjwillis2175]

Outstanding prototype project of craftsmanship👍

[@ethanlynch3639]

I love watching you try things you aren't super familiar with and experiment around the problems

[@RIPvizzini]

I love what a silly beefy little moth this is

[@Unknown15916]

It is good that at 8:30 you saw that it was tail-heavy and moved the battery foward. Best to change only one variable at a time though (IMO).

[@johnathanwatsonson6009]

you are a very talented engineer. I like watching your videos.

[@pa4tim]

Mabey first make it work as a glider, then add thrust by a flapping tail and then add the flapping wings. Birds of prey also are great gliders. We had a dovesnest in a three where you could not leave by direct climbing. They let themselfs fall out of the three, gain some speed while gliding down and then start flapping and gaining altitude

[@SonGoku-rl9qf]

Great Job Sir!

[@TheRealAlpha2]

The size this thing is getting, it's starting to feel more pterodactyl like than bird like.

[@IanSlothieRolfe]

If he makes it just a bit larger, he'll be able to strap himself into it and fly off!

[@impuls60]

I would instead buy a quality motor with more coils and lower kV. That would make the job for the esc much easier. Also I suggest using a drone esc, they have much better modern transistors so they are atleast 2x as powerful for the weight than the one you are using. I have that motor and its not good btw. Adding more weight with another gear demands even more of those wings which is already at their limit. A 20g drone esc will outperform that esc lol. Even the dirt cheap drone esc at 20g on Banggood is more powerful than that esc since they use GAND transistors with extremely low Rdson.

[@irkedoff]

Cool project!

[@ArnaudMEURET]

If there’s someone you should copy it’s JSK Koubou. Check out his fantastic series on Orthopters from many years ago!!

[@rzkharris]

Beautiful design work there at 1:45

[@U014B]

Pretty crazy how real birds have all this stuff inside them.

[@NoSuchStrings]

I saw a diagram (of a flying bat) where instead of a belt mechanism they used one small gear (for the motor) and two larger gears. The flexibile wing rods (long flat sticks) are attached to the body as a lever while the inner ends are hinged on the larger gears. As the motor gear spins it rotates the other gear clockwise and the other one connected to it also rotates but counterclockwise. (The gears are arranged flat face forward and the wing rods are hinged on each opposite large gears left and right)

[@ulrichkalber9039]

your Problem could also be that, instead of moving the wings the motor moves the body in the oposite direction. Dragonflies have four wings, two pairs of wings moving in oposit direction nullifying this. if you arrange the wings like an X the mechanics could be at one point, also the forward right wing should be moving with the backward left wing to also balance lift/thrust. in this case the two forward and the two backward wings could actually be conected in a solid fashion, as the left forward wing would move up when the right forward wing goes down, this would also allow the two pairs of wings be driven like the two wings in the two winged version.

[@casualobserver9341]

I think it would help if you glued the frame of the wings onto the fabric while it was under tension, Then just cut around the outside and the rigid frame would hold the tension. Never done this before, just an idea i had.

[@andrewstubbsis]

On the wind up ornithopters the tail is connected by a small steel piece that can be bent to dial in the angle, which was necessary in my case.

[@GeahkBurchill]

You need superglue de-bonder. It’s a solvent for CA glues which are used by model builders and you should be able to find it at a hobby shop

[@aserta]

Drop some sodium bicarbonate over the glue when you make joints like that. Faster, but also creates a far bigger glued area for the structure.

[@10p6]

Nice. I would make the cross spars of each wing flex though when the wings go up like a normal bird to give more lift at a lower speed. You could make a simple Carbon Rod hinge with a little tension from a spring or rubber band that locks flat on the down movement, and allows about 30 to 40 degrees on the up movement.

[@AltMarc]

Either get down on 2s or use a pignon gear reduction on the first stage. Add tail control, my Shrike (from Kinkade) had always a pitch up tendency AT START, but vanished while in flight. The tail is an important part, to trim the bird. Good thing you listen to us, your ornithopter looks VERY promising...

[@wyrefpv9553]

one thing you could do is put a Throttle curve on the radio, or limit the throttle travel. These can be done easily in the radio itself so that you should be able to judge the throttle position easier.

[@davidvwilliamson]

thank you. really cheered me up. keep going.

[@chrissugg968]

You could use the lighter pulley and make a protective guard in front of it by curving the 2mm bendy carbon fibre tubing, in case of another crash.

[@dfgaJK]

I reckon you need a much lower kv motor, ideally a sensored setup.

[@JTCF]

IDea of flapping wings to create lift is based on that you have more surface area when moving wings down than when you move them up. This way, more upward force is generated than downward force (if just talking about the wings - to fly this would also need to overcome gravity). So this extremely simple ornithopter seems to me like a complete waste of energy. Wings have the same surface area when moving up or down and should generate same amount of force, so it would just vibrate in place + gravity. I think simple glider could be far more efficient at flying.

[@EricRobb]

You should also look into getting a lower KV motor and a different esc that is meant for an airplane.

[@oadka]

Hooked to this series, cant wait for part 3!

[@tobywebb2112]

At 8:15 you said there's too much lift. No such thing. It's your cg. That's specter of gravity. For some reason you put your battery at the back wich is pulling the back of the ornithocopter down. Put it in the first third of the craft. Where the "birds breast" would be. Also at the bottom for stability.

[@worldpeace1822]

A bird of prey with wings spasm … very cool project

[@manuelimboden1582]

I was about to order a SWARM eval kit, your coupon code came very timely 😃 thanks! Looking forward to part 3

[@_bluespider5470]

Sewing would be more efficient as to weight and strength than the glue. Use 5 points zigzag and a decent spacement between points for preventing ripping along the sewing. Great project still, sincerely, a kite maker 😁

[@masterpig5s]

Learning to glide with it after getting height and then steering would be great

[@blaccy5991]

Add a springed hinge on the wing so it bends on the upstroke and i think it'll work

[@lucalauro_]

It seems that this type of ornithopter flaps the wings to produce forward thrust and not lift (like the propeller of a plane) and the tail gives pitch control; that's why wings have a "triangular" shape. I think the thing to do is to maximize the forward thrust keeping a bit of tail weight, then wings should automatically produce lift but because they're pushed forward in the air. So try to consider wings like the blade of a propeller instead of... wings (i would maintain max wing axial pitch above 45° to convert the "flapping" in more forward thrust instead of vertical lift) . Finally, for completeness, if you want to actually produce lift by flapping the wings the concept is that they have to produce more uplift in the down stroke than downlift in the upstroke, like other comments suggested; try to take a look at Da Vinci's ornithopter!

[@davidvwilliamson]

remember its torque that breaks things. are you sure it isn't what broke that front wheel. you can make your first reduction stage ever so delicate

[@olsonspeed]

I have been fascinated with ornithopters since I received a windup version back in the 70's.

[@stevenstevenson7291]

I think that a simple PID control system to maintain a set motor speed might be more beneficial than changing gearing or swapping the motor. Since the motor speed is guaranteed to decrease after launch due to the increased load I cant see how it would be possible to overcome the speed issue without modulating the output voltage to the motor, although maybe with a lot of practice you could do it manually with the controller.

[@rustymustard7798]

Oh, and also forgot to mention, about the wing speed, set the end limit/throttle curve on your transmitter to only allow it to whatever percent you want as max to prevent the 'spasms'. A trick you can use for it is to mix one of the dial knob channels negatively to the throttle so that it acts as an adjustable limiter, allowing on the fly speed limit adjustment.

[@HanZie82]

So much potential, love the thing. But some ideas; im guessing the belt driven gear reduction looks very heavy and bulky. There must be better ways. Also the motor is one that is meant for speed not power. You will want to get a motor that has a way lower kV rating. For the rest, it looks really good.

[@danielrisueno8003]

Idk, but I kinda feel that the tail has some important role that is not being fulfilled. It's just a feeling, though, I can't tell for sure.

[@matt7403]

If you connect the motor to a worm drive arrangement, possibly via a carbon fiber shaft running front back, you maybe could get a bigger gear reduction with greater simplicity and at lighter weight...

[@pauljaggers402]

Hi James, with your transmitter you can adjust reduce your throttle (less power) so that you have more resolution. This will mean that you can find the sweet sport to flapping wings with efficacy to over flapping much easier.

[@andrewsolano4957]

Keep going! Don't lose hope!