Heard Greek character briefly rushed to make revolutionary device (5)
I believe the answer is:
rotor
'revolutionary device' is the definition.
'rotor' can be an answer for 'device' (rotor is a kind of device). I am not certain of the 'revolutionary' bit.
'heard greek character briefly rushed' is the wordplay.
'heard greek character' becomes 'ro' (I can't explain this - if you can you should believe this answer much more).
'briefly' means to remove the last letter.
'rushed' becomes 'tore' (to tear around is to rush or run fast).
'tore' with its last letter removed is 'tor'.
'ro'+'tor'='ROTOR'
'to make' acts as a link.
Can you help me to learn more?
(Other definitions for rotor that I've seen before include "one lifting chopper?" , "Rotating part of machine" , "Revolving mechanism" , "Revolving component" , "The machine part moves in a circle" .)