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• n  a propeller that rotates to push against air

• The airscrew must then act as a giant parachute.
• Until 1933 there had been only two major improvements in the paper airscrew invented by Leonardo da Vinci some 450 years before to pull toy helicopters to the ceiling of his study.
• Leonardo da Vinci designed a spiral airscrew in the hope of achieving perpendicular flight.

• airplane propeller
• prop