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Old Jan 14, 2014, 03:41 AM
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Ornithopter gear mechanism

Greetings

Hello friends . I have started to work on ornithopter and collected some information but still there are many gaps left . I hope anyone to clear the gaps

1)What should be the gear mechanism for flapping wings ? There are few mechanisms out there . One of them is four bar linkage mechanism . Are there any other mechanisms for flapping wing flight ? Which of those is the best one ? Why ?

2)What should be the gear reduction ? What should be the flapping frequency of the wings ?
Also, birds twist their wings during the flapping to maintain the angle of attack.What mechanism should we follow for twisting ? What should be the angle of attack of the wings?

3)I am thinking to use balsa wood for my ornithopter and ripstop nylon for wings . Do you suggest any other materials?

4)How do you attach the spar rods to the main frame ? How do you connect the flapping wings and the reciprocating motion of the gear?

5)Is there any theory regarding the flapping frequency and the lift of the bird ?

Please help me with my doubts .

Thank you
Sai Kiran
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Old Jan 14, 2014, 11:42 AM
Kjell Dahlberg
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Mallorca Spain
Joined Nov 2005
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You can learn a lot from Kazuhiko Kakuta

http://homepage2.nifty.com/smark/FalcH22E.html
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Old Jan 14, 2014, 09:50 PM
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Thanks a lot
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Old Jan 15, 2014, 05:39 AM
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Here is one more good place to learn from :
http://http://www.ornithopter.de/
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Old Jan 16, 2014, 11:00 AM
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Joined Oct 2013
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I'm a newbie in this field, so correct me if I'm wrong :
2) The frequency is about 3 to 7Hz, it's depended on the size and the shape of the wing. About the twisting things in birds, if the aoa is negative, it creates negative lift but gives more thrust. Beside, the part of the wing near the body has a small changes in aoa and almost always creates the main lift. Therefore, for ornithopters, even without the twisting mechanism, they can fly. In case you want to apply twisting mechanism, you should study the Smartbird of Festo, in which they use servos to twist the wing (using sensors to measure the wind, etc.). The angle of attacks or do you mean the flapping angle?
5) I find this website quite interesting: http://people.eku.edu/ritchisong/554notes2.html
I'm trying to build one on my own... Hope you could build yours soon )
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Old Jan 16, 2014, 11:54 PM
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One more helpful article:

http://groups.csail.mit.edu/robotics...ackowski09.pdf
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