Rotating blades more efficient than flapping wings

dmccormack said:
The weight increase implied in a rotating infrastructure would likely cancel out and gain in efficiency.
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It'd be a hell of a lot easier to build a rotating system than a wing flapping system. The rotating would likely be way less weight as well.

They aren't comparing rotating versus our fixed wings. This is about rotating versus flapping wings in hover.
 
jesse said:
It'd be a hell of a lot easier to build a rotating system than a wing flapping system. The rotating would likely be way less weight as well.

They aren't comparing rotating versus our fixed wings. This is about rotating versus flapping wings in hover.
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If it's so much easier, why are no insects or animals so constructed?

(The only biological equivalent is a samara or maple seed)
 
dmccormack said:
If it's so much easier, why are no insects or animals so constructed?

(The only biological equivalent is a samara or maple seed)
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Possibly because converting a push/pull motion (like muscles or pistons) to rotary motion and transmitting it outside of the body requires seals that potentially leak over time. Leaking is bad because bacteria and viruses can leak into the organism.

I suppose an organism could have been constructed with magnetic minerals (remember bone is a mineral structure) to transmit rotary motion, it wasn't done on this planet. Also, one theory is that wings evolved (or were intelligently designed- I'm not going into that discussion) from something else like legs or cooling devices that flapped rather than rotated, and the motion was kept until this day.

Thr rotary motion was easier for us to construct into machines than flapping- a steam paddle wheel boat is much simpler than the mechanism for moving oars by steam.
 
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dmccormack said:
If it's so much easier, why are no insects or animals so constructed?

(The only biological equivalent is a samara or maple seed)
Click to expand...
I can't think of something in nature that involves fast non-stop rotary motion in one direction under constant power.

That is something that we can build rather easily. Trying to construct a flapping system on the other hand would be by far more complex. There is a lot to the flapping of those little insect wings.

What is easy for nature -- may not be easy for us. What is easy for us -- may not be easy for nature.
 
Jesse- you are correct on the macroscopic scale. On a microscopic scale, some bacterial and at some sperm flagella are driven by a rotary engine based on a protein engine and powered by moving protons (hydrogen ions) or sodium across a gradient.

On a larger scale- nature found it easier to go with the push/pull system. Not to say it couldn't be done- electric eels (and a few other species) store a decent amount of energy to run an electric motor for at least a short time, but earth's biology didn't go that wat (efficiency?). The effieiency of energy conversion in muscles also put our machines to shame.
 
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