Luuk Steitner Posted November 1, 2009 Posted November 1, 2009 I'm starting a new project in my (rare) spare time. I'm planning to build a Meganeura, an ancient dragonfly that was extinct a long time ago. These insects had a wingspan of 70 - 75 cm (~ 2.4 ft). I'm not not building one in A:M, I'm building one for real, RC controlled and supposed to fly. Well, actually it doesn't have to be able to fly in our current atmosphere, this is an experiment to see if a dragonfly of this size could fly with the atmosphere pressure as it is now. The reason for this is that some scientists have reason to believe the atmosphere pressure was much higher in those times, estimated about twice the current pressure. I think it would be almost impossible for a dragonfly of this size to fly with the current pressure (I won't go into too much technical details here), so if this experiment shows this is true (I will be testing with high pressure as well) this may add some proof to this theory. First I have to make sure this machine flaps his wings just like a real dragonfly and not like a ornithopter (common robotic bird build by hobbyists). The mechanics for this will be quite accurate so to prevent I will have to build many models before I get the correct wing movement, I decided to build a model in A:M first, rig it and simulate it. I've started this today and so far it's working out quite well. Here's what the Meganeura must have looked like (this is a model): Here's the rigged mechanic I've build so far: I took a lot of time to get a rig I could easily simulate. I started out with only one wing and got this working. You may notice it is not 100% correct yet. I 'm not sure if I will be making sure the tiny details are correct too, as long as the wing movement is good enough I'm happy. The first test is already very close to the movement I was looking for: test01.mov When I got everything simulated like it should I'll be redrawing this in AutoCAD so I can CNC cut the frame and gears. I've already started on building the wings using carbon rods. Quote
NancyGormezano Posted November 1, 2009 Posted November 1, 2009 OMG - The world is not safe anymore !!!! Yeeee hawww!!! This sounds terrific...given the great success of your "Flying Dutchman" - I have no doubt this adventure will be great fun to watch (gee - I didn't know dragonflies had round serrated gears at one time .... ) What's the # of flaps/second projected to be? Quote
MJL Posted November 1, 2009 Posted November 1, 2009 An interesting project to say the least. Having followed your progress on the Flying Dutchman, I'm very much looking forward to following your progress on this one. A very interesting hypothesis, good luck proving or disproving it either way. Quote
Hash Fellow robcat2075 Posted November 1, 2009 Hash Fellow Posted November 1, 2009 Sounds great, I'm eager to see it! Quote
HomeSlice Posted November 2, 2009 Posted November 2, 2009 Attack of the Giant Killer Dragonflys"! That sounds like a great "B" movie. Quote
tbenefi33 Posted November 2, 2009 Posted November 2, 2009 Put a small video cam in the head you got a cool surveillance robot. Quote
Eric2575 Posted November 2, 2009 Posted November 2, 2009 I am going to call you DaVinchi from now on. I love the things you come up with. Quote
Hash Fellow robcat2075 Posted November 2, 2009 Hash Fellow Posted November 2, 2009 I wonder what the premise is that they couldn't fly in today's atmosphere? There are things that fly today with less wing area to body weight than that dragonfly would have. Put a small video cam in the head you got a cool surveillance robot. No one will be suspicious of a giant prehistoric dragonfly following them. Quote
Luuk Steitner Posted November 2, 2009 Author Posted November 2, 2009 I wonder what the premise is that they couldn't fly in today's atmosphere? There are things that fly today with less wing area to body weight than that dragonfly would have. It's in the way they use their wings. The wings are not gliding through the air generating lift like birds or airplanes, but each time a wing flaps it is creating a high pressure turbulence below it and a low pressure turbulence above it. The pressure difference these turbulences generates lift. This can only work if the wings flap fast enough. No problem for a small dragonfly, but if a Meganeura would flap it wings fast enough in this atmosphere it's wings would break, or at least bend so much they will not work properly. Right now this is just guess work, so I may be wrong. It's almost impossible to make a reliable calculation on this since the only evidence for Meganeuras we have are the fossils. The fossils do not tell us how strong the wings exactly are but from the image visible we can see the wings had an even weaker construction compared to modern dragonflies. From my experience in building many rc airplanes and ornithopters it get's an easy guess. But it's still a guess. If this is all true, the only way to make the Meganeura fly with an acceptable flapping frequency is to raise the air pressure. Two times the current atmosphere pressure seems enough to me. I guess we'll find out soon. Quote
Hash Fellow robcat2075 Posted November 2, 2009 Hash Fellow Posted November 2, 2009 Attack of the Giant Killer Dragonflys"! That sounds like a great "B" movie. One of my most-remembered movies from childhood had a sequence with such a prehistoric dragon fly, although it wasn't attacking anyone. Now that I think about it it looks like he's got those wings flapping over a much larger angle than a real dragon fly would , but maybe it made for better animation. Or maybe that's the secret of how they flew! Quote
Luuk Steitner Posted November 2, 2009 Author Posted November 2, 2009 Nice! I don't think they would have flapped over such a large angle. The first reason is that the actual lift provided there would me minimal, second this would distort the turbulence effect they need to fly. Quote
Paul Forwood Posted November 2, 2009 Posted November 2, 2009 Another fascinating project, Luuk! Quote
Gerry Posted November 2, 2009 Posted November 2, 2009 I guess there's a good reason they're extinct! Quote
agep Posted November 3, 2009 Posted November 3, 2009 Interesting project! I hope you will keep us updated when you start the building of it? Quote
Xtaz Posted November 3, 2009 Posted November 3, 2009 Hi Luuk... I can´t find in your site where I can order my own dragon fly Keep us updated... Quote
nino banano Posted November 3, 2009 Posted November 3, 2009 Hi luuk it sounds good, I hope to see advances of it, greetings Quote
Luuk Steitner Posted November 3, 2009 Author Posted November 3, 2009 Hi Luuk... I can´t find in your site where I can order my own dragon fly Well if you want to order this one (physical version) you'll have to be patient. It may take a while to finish the first one as I'm spending most of my time now to get Zign Track 2 ready a.s.a.p. I've donated the dragonfly on my website for the extras DVD a couple of years ago, so that one is for free Quote
Luuk Steitner Posted December 12, 2009 Author Posted December 12, 2009 This project is progressing very slow but I've got some more progress to show. I've got all wings hooked up now and the simulation is exactly doing what I was hoping for. I've also finished building all four wings (just the carbon frame for now). Here's some pics and animation: test02.mov Quote
HomeSlice Posted December 13, 2009 Posted December 13, 2009 That's so cool Luuk. Hope you succeed. I think that is the first time I have seen someone prototyping a real world object in AM. Once you get the idea worked out, do you move to a CAD package? Quote
Hash Fellow robcat2075 Posted December 13, 2009 Hash Fellow Posted December 13, 2009 Very clever mechanism! I have increased respect for dragon flys after seeing that. We used to have huge dragon flies in Minnesota where I grew up but I don't see many here in Texas. Quote
Luuk Steitner Posted December 13, 2009 Author Posted December 13, 2009 That's so cool Luuk. Hope you succeed. I think that is the first time I have seen someone prototyping a real world object in AM. Once you get the idea worked out, do you move to a CAD package? Yes, I'll be using Autocad to make the final drawings so I can CNC cut the parts. The great thing about A:M is that I can see how well the mechanics does work before I build it. Very clever mechanism! I have increased respect for dragon flys after seeing that. We used to have huge dragon flies in Minnesota where I grew up but I don't see many here in Texas. Huge compared to this one? By the way, I should not get full credit for the design of the mechanism. It has been done by other ornithhopter builders before so I have based this design on other models I've seen. I've altered the design so it would work for my dragonfly. Quote
Paul Forwood Posted December 13, 2009 Posted December 13, 2009 Very impressive, Luuk! Is this first prototype aiming at just getting the dragonfly to hovver or do you have some clever mechanism in mind to alter the path of the wings to give forward thrust, reverse thrust, tilt, etc? Very clever stuff and I wish you every success with this project. Quote
Luuk Steitner Posted December 13, 2009 Author Posted December 13, 2009 Very impressive, Luuk! Is this first prototype aiming at just getting the dragonfly to hovver or do you have some clever mechanism in mind to alter the path of the wings to give forward thrust, reverse thrust, tilt, etc? Very clever stuff and I wish you every success with this project. Two servos alter the pivot hinge positions of the wings. This will change the angle of attack of the wings. This way I can control forwards/backwards speed and yaw. Varying the flapping frequency will make it climb, hover or descent. Quote
TheSpleen Posted December 13, 2009 Posted December 13, 2009 Very clever mechanism! I have increased respect for dragon flys after seeing that. We used to have huge dragon flies in Minnesota where I grew up but I don't see many here in Texas. We have tons of em here in Houston. I'll bet it's cause Dallas can't play sports. Dragonflys hate that. Quote
Eric2575 Posted December 13, 2009 Posted December 13, 2009 We must stop Luuk, this is the beginning of the end, where flying mechanical beast fill the sky and take over the world. Must stop Luuk, must stop Luuk, must sto... Quote
Paul Forwood Posted December 13, 2009 Posted December 13, 2009 Two servos alter the pivot hinge positions of the wings. This will change the angle of attack of the wings. This way I can control forwards/backwards speed and yaw. Varying the flapping frequency will make it climb, hover or descent. I should have known that you would have all of the bases covered. Awesome! (I don't use that word often) Quote
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