Engine that’s labouring to purr when hit in the centre (9)
I believe the answer is:
turboprop
'engine' is the definition.
(I've seen this before)
'labouring to purr when hit in the centre' is the wordplay.
I cannot really see how this works, but
'hit' could be 'bop' (bopping is a kind of hitting) and 'bop' is found within the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'that's' is the link.
(Other definitions for turboprop that I've seen before include "Pub torpor (anag) - type of aircraft" , "It may still take off" , "Type of aircraft engine" , "Type of aero engine" , "Jet engine with the turbine coupled to a propeller" .)