Originally Posted by
treadigraph
The C-5A had a pretty distinctive howl on take off or when reverse thrust selected - those TF-39s...
The Harvard was banned from Biggin for a bit, but there is one based there again now - another aircraft I occasionally hear in the circuit from five or six miles away when the wind is right.
I believe the TF-39 was the only high-bypass engine to have inlet guide vanes for the fan. That basically makes it a huge siren for noise purposes (which is why none of the high-bypass engines for commercial aircraft have fan inlet guide vanes as they have to certify for noise).
I think all the C-5s still flying have been retrofit with CF6-80C2 engines - so now they sound like a 747-400
