From what I understand, in addition to
lowering the resonant frequency it would also dissipate some of the resonant energy
through flex-induced heating – thus damping the system somewhat…. Exactly
what one would want (verses springs which dissipate very little). Other damping
schemes which I have heard of include both springs and hydraulic damping in
combination.
Cheers,
Pete
Europa builder and single rotor dreamer.
PS- anyone out there care to comment on my
previous question of whether single-rotors do indeed experience torque
reversals?
-----Original Message-----
From: Jim Sower
[mailto:canarder@frontiernet.net]
Sent: Thursday, January 22, 2004 2:09 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re:
Torsionals
OK. So Tracy's re-drive is loose. Would
not rubber bushings make it MORE loose? Or would that turn on more
complex considerations such as the elasticity of the rubber, etc.?
Lookin' for easy answers to hard questions again? :o) .... Jim S.
Al Gietzen wrote:
I realize that these are relative
terms, but my opinion is that Tracy’s re-drive would not be called
“tight” tolerance. There is; what – ½ back and forth
play at the prop tip? As I recall, Tracy had given this some
consideration, and chose to keep the relatively “loose” tolerance.
Subject: [FlyRotary] Re: Torsionals
Assuming (key word here) that Tracy's
PSRU can be regarded as "tighter
tolerances", mightn't rubber
bushings effectively "loosen" the tolerances and
get us INto more trouble than they
get us OUT of?
Just wonderin' .... Jim S.
> Torsional vibrations and
resonance are a fairly complex topic. .. In
> generally tighter tolerances
raises the resonant frequency of an assembly
> and looser tolerances lower
it. Tighter tolerances are generally more
> expensive than looser.
...By the way, since the rotary does not have a
> negative torque region in its
> power curve this problem is
minimal and can generally be handled by some
> simple dampeners such as
rubber disks, etc.
?