Right now that is really the way it is, except the radials do not have an engine damage sound assigned. So, the inline damage sound comes through. There is a jet engine damage sound, but the game does not use it for some reason.
I checked out a few of the engine sounds with Audacity (I think that's what you're using) and it false positives on a lot of the engine sounds when testing for clipping. Audition can clean those spots up to make them invisible to your test, but I thought I would explain what is happening there. A lot of the engine sounds have embedded tracks so that I get the sound I want when the aircraft is moving fast, or diving. So sounds like the radiator cooler are stretched out and mixed with the original engine track, and as the speed builds they reform to their original shape as they get bunched up by the Doppler effect. The stretching causes the amplitude to flatten near the peaks (compression/rarefaction) which the audio application will detect as clipped. This is from the imprecision of digital waveforms instead of an actual artifact.