rotary wing vs aerofoil

rotary wing and aerofoil both are nouns.

Word	Noun	Adjective	Verb	Adverb
rotary wing	Yes	No	No	No
aerofoil	Yes	No	No	No

As nouns, aerofoil is a hypernym of rotary wing; that is, aerofoil is a word with a broader meaning than rotary wing:

rotary wing: the long airfoil that rotates to provide the lift that supports a helicopter in the air
aerofoil: a device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight

Other hypernyms of rotary wing include airfoil, control surface, surface.

rotary wing (noun)	aerofoil (noun)
the long airfoil that rotates to provide the lift that supports a helicopter in the air	a device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight