ELI5: Why is it so difficult for us to just replicate a bird instead of the kind of fixed wing aircraft we have?

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Flapping bird wings are kind of inefficient. They’re great for picking yourself off the ground, but require a lot of energy to keep going Larger birds, which are still small and light compared to an airplane, achieve flight easier by riding updrafts in the air and gliding, with very little flapping at all. This is what the fixed wing aircraft replicates. This has added benefits of less turbulence, with the plane not being pushed up by the periodic addition of lift.


Number one reason is there is no need to. The mechanics and engineering behind a pivoting wing that is also supporting of the weight needed would be complex. Also, the thrust provided wouldn’t compare to that of modern engines. So more complex with more things to go wrong for less benefit.


It’s not hard…. At the size of a bird. Beyond that, things start to fall apart Birds wings cannot carry much. There’s this fact of the universe called “the square cube law”. Tldr: if you make something bigger, it’s weight will increase faster than its size. This law is why there aren’t many elephant sized birds. If they got too big, their bones would be too heavy. We can technically make bird-sized machines, but bird-like wings don’t really scale up well. They get too big, they just can’t support their own weight. In fact, it’s why there aren’t many elephant-sized animals. Most could not handle the weight of being that big Tldr: Birds just aren’t the best at flying. That goes to aero engineers.


Actually, I know it may not be intuitive, but helicopters fly like birds. Unlike fixed wing aircraft, helicopters manage lift, direction and thrust with their blades, as birds do to their wings. While airplanes handle lift with their wings (and other lifting areas), thrust with the motor and direction with flight control surfaces (e.g. ailerons). If your question is why don’t we have airplanes which flap their wings: basically we don’t have any kind of material which could handle that kind of forces. Additionally, as others have said, it would be very inefficient.


One thing that hasn’t been mentioned either is that the wing shape of a plane (airfoil) does in fact replicate/is very similar to a birds wing in cross-section.