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Re: Rotational inertia?

To: spitfires@autox.team.net
Subject: Re: Rotational inertia?
From: "Ryan Smith" <shmitty99@hotmail.com>
Date: Tue, 01 Jun 1999 18:31:55 PDT
Here's a mathmatical proof.

for a purely rotational example:
      KE=0.5Jw
Where KE is kinetic energy, J is the MASS moment of interia, and w (actually 
omega)is angular acceleration defined by vL (where L is the distance from 
the center where the velocity is measured).

Ok assuming your engine can only produce a finite amount of power which is 
energy per unit time, KE is constant or at least has a finite limit.  The 
mass moment of intertia for a disc is J=0.5mR^2.  So if the amount of mass 
is reduced and the radius stays the same the angular acceleration must 
increase to equal the constant KE.

This is simplified since a flywheel is not a true disk but it mass moment of 
inertia obviously is still a function of mass.

Ryan Smith
72 Emerald Green Spitfire
Mechanical Engineering, VPI&SU

>From: Kma4444@aol.com
>Reply-To: Kma4444@aol.com
>To: sPITFIRES@autox.team.net
>Subject: Rotational inertia?
>Date: Tue, 1 Jun 1999 18:45:21 EDT
>
>Technically , it is the moment of inertia . A flywheel that weighs 15 lbs 
>and
>carries it's mass at the extreme egdes as does the 1500 wheel . has a much
>higher MOI than does a 15 pound flywheel that carries it's major mass 
>closer
>to it's centerline .
>A flywheel and clutch package that lowers your MOI will indeed make your
>vehicle accelerate quicker , all other things being equal .



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