Instructables

Desktop Ornithopter

To create a flying machine that simulated bird wing movement ( an ornithopter) but was able to have smooth movement.

The difficulty in creating an ornithopter is the issue of having smooth and consistant wing movement. Many people have tried building these and never quite get the movement right with the wings flapping unevenly.

This little project started about 18 months ago whilst pondering how to do it... this little instructable hopefully explains how I got around the problem.
 
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Step 1: Items used

1. Coffee Stirrers
2. 4mm MDF
3. Motor from redundant 1990's video camera
4. Various cogs and clips from video camera
5. 2mm thick dowels from PC cleaning equipment
6. SupaGlue
7. Twine

Build Time

6 hours

Step 2: The upper mechanism

The main difficulty that presented itself from the beginning was the issue of the smooth motion required to get the wing blades to move smoothly. This diagram shows a schematic overlay of the wing coupling on the ornithopter. The upper wing joints forming a triangle are fixed and the lower (in the current shot) is fixed to the cam. You will note that the distance between the couplings at the low stroke and high stroke is 36mm but at mid point the distance between the central coupling and each out joint is 30mm.

Due to this issue I saw fit to cut a slit in the wing blade (circled in blue on the left) with a length of 6mm, the difference between the maximum coupling distance and the the shortset coupling distance. The couplings were made by drilling a 2mm dowel into MDF and then feeding the blades onto them. The blades were kept in place my minute aluminium washers found in the video camera.
T_T_3 years ago
look at what this person did, it looks pretty simple http://www.youtube.com/watch?v=lhjWX9HAKmQ&feature=related
(removed by author or community request)
i also agree with el_roboto_loco because why else would instructables be called The worlds biggest show and tell?
Actually, it's a good instructable. If he solves one problem, then it might be the missing piece of the puzzle for somebody else who is doing something extreme and novel, but maybe they're stuck on this one item. If somebody does some analysis, and design, and makes a model, then that is a project in itself. Military contracts usually are given out as 3 phases. You submit a proposal for something they are soliciting, and if you win a contract, it's just a study contract to do more analysis and then you do a final report. Phase 2 is to build a working prototype. Phase 3 is production. The point is that if somebody has done some thinking, and some tinkering, and goes to the trouble to make an instructable, then I thank them. Ph.D.s write white papers, etc., which are theories, and theories of operation, and those papers get published. Then, other people get inspired and write a paper and they reference the work in the first paper, and similar papers, and eventually somebody builds something.
budsiskos6 years ago
you can make it smaller by having armA side ways - arm B down at an angle \ and arm c up I OR you can completely eliminate arm c
orni 2.0.bmp
Jezza Bear (author)  budsiskos6 years ago
That is an interesting point. The diagram on the right of your image is worth looking at but I have a feeling (yet to be tested) that it may put a lotof stain on the mechanism....one to test. I have been meaning to post my latest creation which has been sitting on my work bench for the past 5 months where I have used a "conventional" mechanism. Your idea has certainly made me think, thanks for your input.
crestind7 years ago
http://hight3ch.com/post/gorgeous-ornithopter/#more-2382

Here's the one I saw. Amazing. Wood sticks and plastic cloth wings. It seems to be rubber band powered, because there doesn't seem to be a motor. The dual wing design is incredible.

Anyone know anything more about this ornithopter? It's by far the most beautiful and natural looking one I've ever seen. Love to make one, I think.
Jezza Bear (author)  royalestel7 years ago
I have just had a look at the video and paused it at the various points and reckon the cam model is pretty straight forward. I think I may have have a go and make a concept. It appears they are using very light weight material for the wings, possibly fine silk.. I shall have a go tonight and publish a mock up
I was thinking it was a wal-mart shopping bag or something even thinner like a thin paint tarp.
what works well as material for the wings is "plastic" basket wrap tissue, or the same thing in the form of party bags. I got a big roll of the clear stuff (which I had to splash paint on it because I could never find my clear pieces) but it also comes in colors and festive patterns. It's very light weight, and crinkly, but it doesn't wrinkle. It's seems very similar to mylar. I got some from a crafts store, and the party bags at dollar store right next to the first store. It's cheap, too. Also, unlike the normal tissue people use, it's easy to handle, and doesn't stick to your fingers when you glue it. I'll put some pics up later.
cool.
here's a picpic
www.pneumagic.com/instructables/ornithopters
Please post if you have any working ornithopters! Knex seems to be too big for ornithopter joints and such :( Maybe barbecue skewers will work well.
I'm using BBQ skewers. They work great. And I have a very cool linkage for the vertical motion at the crank that I just tested for proof-of-concept, and it works. And, it's frictionless! Also, you don't need to bend any wire as with the typical cranks. Whether it'll fly remains to be seen, but I'll know in a day or two. I just came up with this novel linkage yesterday. As soon as I have something that almost flies I'll do an instructable. I've already started taking pics as I go. I'm also making a hybrid ornithopter, which has a propeller, and I'll put that in the instructable, too.
You can sort of see the gears around 1:04 on the video. I still can't tell what it's powered by though. I can't see a motor or anything.
I think that its rc. During the part of the movie where the guy holds it you can see that it is variable speed and when there is a closeup of the front mechanism there is what looks like an outrunner brushless motor behind it. There also looks to be a small lipo battery right in front of the rudder, that combined with the mess of wires, flying small rc in gymns being common, and another plane in the background for parts of the movie just adds to my theory.
There seems to be a very similar model being sold here.
Jezza Bear (author)  royalestel7 years ago
rofl....I was looking at that very page last night...I am tempted to buy one and then get ideas from them...
lightninjim7 years ago
ROYALESTEL WROTE:"anyone know more about this ornithopter?" posssibly lol Yusuke Takahashi built this remarkable infrared remote-controlled ornithopter based on The Ornithopter Zone's Luna kit. The ornithopter uses a 0.4 gram infrared receiver desgined by Koichi Tanaka. In contrast to the flat tail of the standard Luna, Takahashi's version has separate rudder and elevator surfaces with magnetic actuators(standard indoor modelling practice). The ornithopter also has proportional throttle control. It uses a super slick orange motor.What makes these motors so special? First, they have a weight of 2.7g which is about 1.1g lighter than a typical M20-LV motor. They also have reasonably strong magnets and will attract objects to them. Not all coreless pager type motors have magnets this strong. They also come with various motor windings identifiable by the colour of the motor. The power source was a 70mAh Li-po providing around 10 mins flight times
Jezza Bear (author)  lightninjim7 years ago
Thanks for the feedback, I have been around that site so many times that I hadn't even noticed that section. I am planning the next stage of this project and just getting my materials together.
rickharris7 years ago
have a look herehere
jtobako7 years ago
in step 2, the upper mechinism, you would get better strength with a guide that goes around the spar rather than cutting a slot in the spar. something like a staple or eye hook, even if it had to be able to turn in the suport because of tight tolerances. when you start worrying about weight, i've seen where balsa wood is impregnated with super glue to harden some surfaces without adding much weight.
Jezza Bear (author)  jtobako7 years ago
Hi There Funnily enough I tried that as an option and whilst agreeing, I decided not (for this model and probably others) only because "it was another bleeding part ready to go wrong" :-) In the smaller model I actually built a flexible rod that did work. Thanks for the idea, it would certainly be an option for the future. The super glue idea is very good, I have hardened pegs with this idea before but good to share.
crestind7 years ago
Awesome! I've been wanting to build one ever since I learned about these (last month lol)! I understand the basic concepts, and I'm probably going to use Knex for movement parts. A few questions- -Wing angles. So I'm sure the front tip should be up to generate forward movement. But what angle would be the best? -Horizontal wing movement piece that runs through both grooves. That also serves to ensure both wings move in unison? -Even though it's balsa wood (I think), it looks really heavy even without the base. So how fast does it go? (layman terms please - walking speed, light jog :P) -Is there an "optimal" wing width per weight? Can you post a few side views please? I want to see if you had any rear fins and such and width of wings. Sorry for all the questions, but this is really cool! Since I have no motor, I'm going to try and make a lightweight rubber band powered version.
Jezza Bear (author)  crestind7 years ago
Hi There Thanks for the comments. This one was purely a concept model and just a desktop version, it was way to heavy for it to fly properly. The smaller one in the first image was designed "on the fly" (pardon the pun) and actually flew and then shattered. When I get home tonight I will certainly photograph a side view for you to look at he rig.
Williz7 years ago
Be easier if you used a step by steap guide on how to MAKE it. Not just photo's of it done and instructions. Makes it hard for some people.
You need to read the intro to realize this is not how to make it, just how to fix a common problem ;)

Many people have tried building these and never quite get the movement right with the wings flapping unevenly.... this little instructable hopefully explains how I got around the problem.

;)
Jezza Bear (author)  Williz7 years ago
I hope you note the very last sentence of Step 4 I have made: "...the best way to get linear motion from circular" I thought Step 2 and Step 3 of my Instructable showed the steps to create linear motion using calculations.
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