capstan vs propeller shaft

capstan

noun
  • A vertical cylindrical machine that revolves on a spindle, used to apply force to ropes, cables, etc. It is typically surmounted by a drumhead with sockets for levers used to turn it. 

  • A rotating spindle used to move recording tape through the mechanism of a tape recorder. 

propeller shaft

noun
  • the shaft which connects the gearbox to the differential on the axle of a rear-wheel-drive or four-wheel-drive vehicle. 

  • The shaft which transmits the rotary motion from an engine to a propeller, as on a ship or aircraft. 

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