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Ornithopter flight problem

  1. Aug 22, 2013 #1
    i have designed and fabricated an ornithopter with flapping frequency of 4Hz and span of 1m...... Actuation of wings is perfectly fine but it is unable to generate lift.....what are the possible amendments should i do to make it fly.....and it is a bit over weight i-e 700g....
     

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  2. jcsd
  3. Aug 22, 2013 #2
    Tie it to helium balloons.
     
  4. Aug 22, 2013 #3
    Its too heavy and the thing itself looks to big to generate lift without flexion of the wings
     
  5. Aug 22, 2013 #4
    But i am not an expert on unsteady low RE flight
     
  6. Aug 22, 2013 #5
    I'm no expert either, but I agree, the biggest problem is probably weight. But a close second is the wing dynamics. You're probably getting just as much downward thrust on the wing upstroke as you are in the downstroke. Any way you can allow/induce more flexion in the wings on the upstroke?
     
  7. Aug 22, 2013 #6
    You could probably easily do this just inserting a second joint about 1/3 down the way. Take a look at some photographs of birds that are a similar dimension. Also, what airfoil are you using?
     
  8. Aug 23, 2013 #7
    i am using parachute cloth without any airfoil.
     
  9. Aug 23, 2013 #8
    Yes, you are right weight is the biggest issue but i am unable to reduce the weight. As in the wings, i am using the parachute cloth which is heavy and is not generating required lift....suggest me the material for the wing.Thanx
     
  10. Aug 25, 2013 #9
    If you are producing equal amounts of vertical force on the upstroke and downstroke, and it looks like you probably are, then reducing the weight won't really matter. As was mentioned above you need to improve the wing design. It is looking pretty cool though, good luck!
     
  11. Aug 28, 2013 #10
    you mean to say that the fabriction of designed wing is not good or the design itself.....how can i improve it??
     
  12. Aug 28, 2013 #11
    You need the wing to flex or deform the reason why lift is generated is because of the asymetric vorticies generated by different wing flexions on the upstroke and downstroke.
     
  13. Aug 30, 2013 #12
    Also, any heavy materials you may be using are a bad choice. Lightweight is the name of the game in all of aeronautics. Sometimes one might trade a little weight for some performance gain elsewhere (firepower, maneuverability, etc) but weight is always a major concern.

    Many RC enthusiasts use shrink wrap plastic covering sheets to cover their wing and fuselage structures.
     
  14. Sep 3, 2013 #13
    for test flight of ornithopter i should throw it with head-wind or tail-wind ??
     
  15. Mar 13, 2014 #14
    1] You need to arrange wings such that they should have some angle of attack.
    2] Only straight up-down flapping won't work, give in little elliptical motion, i.e while downstroke they will come down via front perimeter of Circle and when they go up they will use back perimeter. Hint: Bird's doesn't just flap wings up and down, they use slightly circular motion.
    3] The frame you used seems to be heavy, in reality you don't need it for proof of concept, you can get rid of it. Just attache your motor/gear to the rod.
    4] Instead of cloth, you can use polythene, which will be way more lighter than cloth.
    5] Instead of aluminium, you can use light weight wood e.g. balsa wood or similar or plastic straws together.
    6] Implement all of the above points and your bird will start flying as you see other birds...

    Best luck.
     
  16. Mar 13, 2014 #15
    Can someone tell me if there is any value (monetization possibility) in such models or are they strictly a curiosity? Because I see many people absolutely amazed by ornithopters, but I see no practical use for them.
     
  17. Mar 13, 2014 #16
    Toy industry. Hobby. Educational with practical.
    Do you see people fly small helicopters indoor as well as outdoor? The value is just pure Joy and people pay for that.
     
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