autogiro vs eggbeater

autogiro

noun
  • An aircraft in which lift is provided by unpowered rotating wings and thrust is provided by a conventional propeller. 

eggbeater

noun
  • A helicopter. 

  • A kitchen utensil that uses rotating blades to beat eggs. 

  • A swimming stroke involving alternating kicks. 

  • An outboard motor. 

How often have the words autogiro and eggbeater occurred in a corpus of books? (source: Google Ngram Viewer )