Robert Feldman wrote:
Leonardo DaVinci put errors in the drawings for his
"tank."
But then how many people have built it!
Ornithopter's are a lot more fun. :)
The unrealized dream of aviation -- man powered Ornithopter.
http://web.kyoto-inet.or.jp/people/kazuho/index-e.htm
------
To get back on topic about babbage's drawings,
from what I read it was mechnical design that
could not be produced with 18th century mechanical
enginering.