The most common and most likely answer to this crossword clue is the 8 letter word TURBOJET
I've seen this crossword clue in The Guardian
T
U
R
B
O
J
E
T
Buddy explains!

The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does TURBOJET mean?
TURBOJET noun- A jet engine that develops thrust solely from high-speed exhaust gases expelled from a turbine that drives a compressor.