Message-ID: <002601c3e28a$74ac9ee0$ec8fe150@nscvsy6kod72n8>
From: "Tony Dolby" <tony.dolby@tiscali.co.uk>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-2946294@logan.com>
Subject: Re: [FlyRotary] Re: Torsionals
Date: Sat, 24 Jan 2004 14:57:57 -0000
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From: "Marvin Kaye" <marv@lancaironline.net>

> the firing pulses are simply the "exciters"...
>Think about a guitar or piano string...
>The single rotor e-shaft is a little stubby
> thing, with much more torsional rigidity than that of a 2-rotor.  Ergo,
its
> resonant torsional frequency is probably considerably higher than the
> 2-rotor's.  Further, if you consider the resonance of the total system, if
any
> one component has a higher resonant frequency then the total system's
> resonance goes up with it.
(Much snipping..)

Ah yes, thanks Marv. I can picture the two shafts side by side but made
into tuning forks, the frequency difference becomes obvious. I was thinking
of the
firing frequency rather than the "ringing" frequency of the shaft.

> Think about the discussion here to date... if the
> drive coupling (one component) is tight and stiff, the system's resonant
freq
> is raised.  Loosen up or soften that coupling, and the system's resonant
freq
> is lowered, which, as Tracy has so eloquently explained, is the reason
that
> his drive system works so well.

Being a well read Tracyphile I wouldn't think of rocking the boat but I
thought I
understood that the torsional had to be sort of "let out" or allowed to move
and
not connected solidly to anything, vis a vis the dyno shaft blow up in
Tracy's writings.

Otherwise, by George, I think I've got it!

Great Info, Thanks,

Tony