Originally Posted by
Mwenenzi
A
PW R-1830 radial on a DC3. No better aircraft engine noise than a piston radial
4 Wright turbo-compounds on a DC-7C or L1049. Sometimes that was subsequently reduced to 3 though

.
More modern, the Dash-7 in which the revs and noise didn't seem to change at all throughout the flight.
Jets - straight-pipe water-injected 707 or anything with RR Speys.
Modern jets - pah !