What was identified as the primary hurdle preventing the success of Leonardo's atmospheric flight designs?

Answer

Power

The primary hurdle for all his atmospheric designs, including the helical airscrew, was insufficient power—specifically, lacking an engine powerful enough to rotate the rotor against its own weight.

What was identified as the primary hurdle preventing the success of Leonardo's atmospheric flight designs?

#Videos

Thousands of Pages of Inventions, Ideas and Flying Machines | PBS

I made all of Da Vinci's Inventions! - YouTube

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