It turns up and down (5)
I believe the answer is:
rotor
This clue is a double definition.
'it turns' is the first definition.
(I've seen this before)
'up and down' is the second definition.
(Other definitions for rotor that I've seen before include "Eddy" , "Turning part of machine, palindromic" , "Machine part that turns around" , "Revolving part of a machine, a palindrome" , "Helicopter supporter" .)