

Winged Robots May Shed Light on Fly Aerobatics - Mz
http://www.sciencenews.org/view/generic/id/350138/description/Winged_robots_may_shed_light_on_fly_aerobatics

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Mz
Excerpt:

"At small scales, drag and friction gain importance in flight dynamics. As a
result, many components in large robots, such as gears and pulleys, don’t work
in tiny flying machines."

So they are the size of a penny.

