Steven brings up good points about flywheels and rotating mass. We know
that the larger the diameter, the more energy it takes to turn it.
Especially if a major part of the weight is at the perimeter. And it
usually is. Big budget race teams reduce the weight/diameter of both
flywheel and clutch. I'm sure that their light wheels and tires help
with this as well. They make up for the smaller diameter tires with
taller gearing, when necessary.
Robert Mc perhaps kiddingly suggested a heavier one to reduce stalling.
The stock flywheel certainly plays a part in a smooth transition when
engaging the clutch, and idle speed steadiness.
Harmonic vibration on the TR six crank comes in between 6200 and 6350
rpm. This is what is to be avoided, or raced thru. The idea here is not
to be caught at this engine speed for long. Lots of good info is in
print about this, so no need to carry on much.
Dick
From: gtg124h@mail.gatech.edu(Steven Altomare)
Subject: Re:.....flywheel
Quoting Sally or Dick Taylor <tr6taylor@webtv.net>:
I feel as Mark does in this matter of the "lighter flywheel". Once the
clutch is engaged, the whole drive train becomes part of the flywheel
and the effect of lightening diminishes greatly. At least so far as
acceleration is concerned.
Steven writes:
In speaking of rotating objects, mass isn't as important as the moment
of inertia is. The moment of inertia takes both the mass and the
distribution of the mass into account. If the flywheel could be
approximated as a flat disk, I = .5*mass*radius^2. If we really wanted
some improvements, reducing the radius would be the way to go! Of course
that really wouldn't work...
So the thing is, just because something is heavy doesn't necessarily
imply that the moment of intertia is large because the radius of
rotation could be small. Relative to the radius of a flywheel, the
radius of the driveshaft is very small.
Having said that, removing the possibility of harmonic vibrations could
be benefit enough in installing a lightened flywheel (I guess depending
on what RPM the vibrations occur at). I would have to think the ligher
flywheel would also offer some performance improvement, however the
performance to $ ratio could be well debated (as it has been!)
Steven Altomare
74.5 without a light flywheel
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