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Picture of Mini-Ornithopter Prototypes
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Somewhere around 1996 I got caught up in that Magic: the Gathering card game that was going around like the flu. One of the cards, the Ornithopter, had a picture of a set of wings made from sticks and cloth that I found facisnating. I haven't played the game in years, but that card got stuck in the back of my memory, probably because its name is fun to say.

I've had a resurgence of interest in these devices thanks to the growing popularity of micro air vehicles (MAV), like palm sized helicopters and quadcopters, and suddenly had the need to try build my own ornithopter. This Instructable documents my recent  attempts at crafting my own micro-orithopter from inexpensive components. This is really more of an Instructadon't, as none of these prototypes actually fly. I'm close to having a working version in the air, when that happens l will also create new Instructado using a more conventional format.




Project Goals
  1. Design and fabricate a palm sized flying machine using 3D printed parts
  2. Non-3D printed pieces, such as structural material and electrical components, must be cheap and easily to find.
  3. Printed parts should total no more than $10 when being made from ABS plastic or similar.
  4. Total cost should not exceed $40, including RC.
  5. Design and fabricate a Infra-red receiver and transceiver for remote control
  6. Small is the name of the game! I'm shooting for a wingspan of less than six inches.

Materials Used
  1. Spring Steel, aka Music Wire. hobbylinc.com
  2. Guitar Wire
  3. Miniature Motor, common pager style solarbotics.com
  4. 40mAh Lipo Battery sparkfun.com
  5. Tissue Paper
  6. Plastic Film, various thicknesses
  7. Sewing Pins
  8. Gorilla Glue

Design Software and Tools
Objet Printer
Up3D Printer
123D beta9, Autodesk Inventor Fusion
Dremel, scissors, wire cutters, micro drills
 
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Step 1: Initial Design and Material Testing

While building the first design I had three main objectives: to make a working mechanism, to test different materials for strength and flexibility and, most importantly, to make it look cool. I know next to nothing about the science of flight, so I wasn't all that surprised when the first prototype nose dived. The important thing was that I learned why it was failing and how I might correct it.

In the pictures you can see parts of the ornithopter printed from different materials.  These were all printed on Objet 500 UV cure 3D printers that are able to mix a rigid material with a flexible material while printing. To test these materials  I made several separate prints using different ratios of rigid and flexible at different thickness. The parts were then assembled to a semi-functional state and stress-tested to determine what combination made for the best ornithopter.

The type of material that comes out of these photopolymerization printers is very similar to plastic, but it's not quite the same. Thin pieces tended to be floppy, and thicker parts were prone to snapping. These materials were not intended to be made into mechanical parts. As far as durability was concerned, I was having much better luck with pieces made from ABS plastic printed by an Up3D. ABS is plastic, and I think that will be strong, flexible, and light enough to be used in the final version.

I learned a lot from this first test model. For one, the small gear ratio didn't provide enough  torqueto flap the heavy wings. More importantly, I started to realize that slapping on ad hoc paper wings and expecting the craft to actually fly was a bit optimistic. I did find a suitable material, the gears and linkages were working, but the wings were flat and lifeless. I went back to my virtual drawing board and started on the revisions.

Step 2: Version Two - Less Yap more Flap

Having gotten the mechanics working, it was time to move on to the secrets of flight. In the first model I felt that the wings weren't flapping fast enough and that they were not large enough. To shore up these problems in the second version I used a 64 tooth gear instead of a 32, giving the wings much for flapping power. They also attach further back than before to create more area and to produce a more curved wing.

I'd bought a bag of ice and decided that the plastic the bag was made of would work well for wings. I very, very, carefully applied glue to the wire struts, folded the edges of the plastic wing over, and then applied generous pressure to squeeze the glue down the full length of the seam.

Sadly, after all my hard work and perseverance, this version also failed to fly. When thrown it did glide in a far less vertical fashion than the first, and the ABS did stand up to crashes, but I really didn't get the impression that any lift was being generated. After this defeat I realized that it was time for some research.

Step 3: Going Further

Picture of Going Further
600px-Venation_of_insect_wing.jpg
Up to this point the only real research I had done on how ornithopters achieve flight amounted to nothing more than a few google image and youtube searches. I had assumed that one simply makes a mechanism that goes up and down, slaps some wings on it, and the machine couldn't help but fly. It looks so easy in the videos after all. This is where I'm at right now with the project, two prototypes made but not much flying going on. I finally did do another search and took the time to read the results.

As it turns out, there is a lot I don't know about flight! Things like "wing stroke amplitude" and "lift distribution" which, to the uninitiated like myself, sound like they may be kind of important factors to consider in the next design. I eventually found a few websites that go into every little detail of how ornithopters fly, including different designs for the wings. Most of the technical jargon is a good meter over my head, but I think I've gotten the jist of it from the pictures.
www.ornithopter.de, www.ornithopter.org (Ornithopter Zone)

As I understand it, an ornithopter's wings need to twist during flight so that they generate both lift and thrust. This curvature creates an airfoil that, at some points along its length, produces lift during both the up strokes and down strokes. Thrust is provided by wizards...

I still don't fully understand it, but I'm going to forge a head anyway under the banner of "flex good, no flex bad!" I plan to tweak the design more, use guitar wire for the struts, try a few different hinge designs, and see if I can get one of these bricks in the air. At that point all I'll need to do is design and fabricate an IR receiver / transmitter pair to control it, a project that is a little more within my realm of expertise.

Thanks for checking out my progress so far and learning what you shouldn't do when making tiny flying machines. On the final step you'll find a video collection of actual working models made by people who know what they're doing :p

If you or someone you love has experience building these and would be willing to point out what I'm doing wrong, please do leave a comment!

Huge thanks goes out to Jake and Steve over at Instructables for their help in working out the bugs and with the video. You guys rock!

Step 4: Inspiration

Picture of Inspiration
People have attempting to build ornithopters for a very long time, even before Da Vinci did his famous sketches. Unlike my prototypes, there has been much success in getting them to actually flutter about, they are even available as toys. Universities are working on ways to make them smaller and smaller and the Air-force dreams of swarms of microthopter spies.

Shapeways 3D printed Ornithopter
Rubberband Ornithopter Instructable
www.ornithopter.org
www.ornithopter.de

These are videos of some of the more interesting models that ultimately gave me ornithopter fever.


Butterfly Mimic
Hiroto Tanaka of Harvard University and Isao Shimoyama of the University of Tokyo



Cornell's 3D Printed Hovering Ornithopter



Flapping Wing Micro Air Vehicle (Micro Ornithopter) - 2.17 grams



Harvard Monolithic Bee
I'm not sure if this one actually flies, but the fabrication is really neat. The unit is created as though it were a circuit board, and then popped up and soldered into a mechanical structure.
 



Hummer / Da Vinci RC Ornithopter 10cm wingspan 1.1g
Winner of MAV-07, developed by Petter Muren. It was later made into a toy, but was never mass distributed.


Robo Hummingbird
zohaibgmil7 days ago
zohaibgmil9 days ago

pia787

zohaibgmil9 days ago

ahmad

MohamedZ61 month ago

Can I buy one of those??

laith mohamed8 months ago

I like your work

dav130911 months ago

Do you have the CAD models of all the 3D printed parts line the wings, gears, support etc.; if you do could you please share them

ttia sữa1 year ago

http://tritactiasuahcm.blogspot.com/

Tejas131 year ago

awesomeeeeeeeeeeeee :)
i jsttt luvd it

masonmilby2 years ago
Hello im building an Ornithopter from an old rc heli and I wanted to know if you could give me the inventor models so I could print one myself
Manick Yoj2 years ago
Fascinating and very fun. I love watching and reading the videos and research you've put in here and I wish you the best of luck with your future flights!
spylock2 years ago
Too cool,youre a brainy mug no doubt.
zack2472 years ago
if im not mistaken this works in a very similar way to those "dragonfly" toys that used to be sold, but this is incredibly cool nonetheless!
Tomdf (author)  zack2472 years ago
Oh yeah, you are dead on, I think those toys might have even evolved from versions made by hobbyists. They essentially the exact same thing. I certainly could just go buy one, but it wouldn't be near as much fun for me.

Thanks for the comment, Zack.
zack247 Tomdf2 years ago
of course it wouldnt be as much fun, wheres the fun in simply buying something? :P
stihl882 years ago
http://www.rcgroups.com/forums/showthread.php?t=1073892
Tomdf (author)  stihl882 years ago
Thank you Stihl, that stuff is amazing and preddy much exactly what I'm trying to emulate. I can't believe those guys just up and make their own brushless motors, crazy!
germeten2 years ago
There are some excellent 'thopter videos on Youtube. One particular Japanese inventor builds life-size RC bats, birds, insects, flying reptiles which apart from the squeaking mechanicals are hard to tell from the real thing. He also has several videos of construction techniques and details. See: http://www.youtube.com/user/BZH07614?feature=watch
Tomdf (author)  germeten2 years ago
Whoa, that guy is super human. This link is going to be a big help. Thanks :D
M.C. Langer2 years ago
Beatiful work!!!! :-)
Tomdf (author)  M.C. Langer2 years ago
Much appreciated :D
I love the "Inaugural Flight" video--the device is skillfully made and well thought out . . . also it's inspiring; makes me want to give it a try.
Tomdf (author)  MikeTheMaker2 years ago
Thanks mrigsby
GOOD
Nice stuff!
stihl882 years ago
http://www.rcgroups.com/forums/showthread.php?t=596219&page=55
msurguy2 years ago
Very fascinating info and test development here, Tom! Love the idea to 3D print the parts but afraid they will be too heavy, some of the things could definitely be replaced with Carbon Fiber alternatives for a lot more durability and feather-like weight. I have carbon fiber rods 0.2mm, 0.3mm and 0.5mm diameter that would be perfect for this king of development, I'm sure a hobby store near you carries some thin carbon fiber rods as well (maybe not as thin as mine because these are specialized for MAVs). There are also carbon fiber tubes out there that can house the rods by inserting the rods inside which gives you some freedom of how to make the skeleton of the ornithopter.

Do you want me to find some links for Japanese ornithopter makers? They have lots of tips on their websites and I am sure even the schematics and code for the RX and TX for the lightest models. Just let me know and I'll look!
Tomdf (author)  msurguy2 years ago
Thanks Surguy. I think you are right about the 3D printed parts, the smallest gears it can make are too big for a tiny ornithopter. I am having a lot of fun finding ways to cut weight down though, I definitely want to try some of those carbon fiber rods. I also need to get some sockets so I can make those mini-connectors that you wrote about.

I've got the TX and RX figured out, I think, using picaxe, but if you do run across some cool sites I would sure like to see them.
msurguy Tomdf2 years ago
http://blog.goo.ne.jp/flappingwing/
http://www.oyajin.jp/~toko/contri/2005/index.html
http://blogs.yahoo.co.jp/watasidesuyo49/MYBLOG/yblog.html?m=lc&p=3
trhk.exblog.jp
http://translate.googleusercontent.com/translate_c?depth=1&hl=ja&ie=UTF8&rurl=translate.google.com&sl=ja&tl=en&twu=1&u=http://trhk.exblog.jp/i16&usg=ALkJrhgThzIu18NxaF5fM6wvRuS3hIMPbw
http://blog.goo.ne.jp/kobara3211/2

TX info http://www.kyoto.zaq.ne.jp/tkd/transceivmemo.htm
RX info http://www.kyoto.zaq.ne.jp/tkd/airplaneready.htm

Tomdf (author)  msurguy2 years ago
Wow, thank you. I got a chance to weigh some of the parts I've been using and they are really heavy! My motor alone weighs 2.5g, that's twice as heavy as some of the ones I've linked.
I think I have to make this. Even if it doesn't fly. I know someone with this obsession with thopters and I think he needs one of these. Or three. (I am not an enabler... *shifty eyes*)
Tomdf (author)  Easily a-Mused2 years ago
Be sure to check out the videos and links on the last step for examples of ones that do work.
ynze2 years ago
Wonderful instructable! I find the mistakes and the instructadon'ts at least as useful as a flawless how-to I'ble. Thanks!
Tomdf (author)  ynze2 years ago
Thanks, I figured that at the least they are fun to look at :)
rimar20002 years ago
Amazing work!

I speak without knowledge about the matter, but it seems you have too much demultiplication of the motor.
Tomdf (author)  rimar20002 years ago
Thanks, chances are you are correct. I might give up on using 3D printed gears and get some real ones that supply a better ratio.