("Gordon Arnaut" wrote)\
[snips]
A key concept here is tranmissibility,

Like being in college again. 'Transmissibility' ...ouch, it hurts when I
pee!


There is some good reading at this website, with specific info on how
torsional resonance is dealt with in designing aircraft PSRU systems:
http://www.epi-eng.com/BAS-VibBasics.htm

Site is interesting reading. Worth a look.


Montblack