Musical Finn freaks out after Lewis jettisoned drums (7)
I believe the answer is:
timpani
'drums' is the definition.
(type of drums)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for timpani that I've seen before include "> kitchen equipment?" , "Mini tap on a large drum" , "PM, I ain't (anag.)" , "Something making drumming noise" , "set of instruments" .)