Less inertia means less HP lost. There seems to be a 10-22 percent lost to
the rear wheel due to the transmission, drive shaft and rear gearing.
Another thought is the shorter the drive shaft less flexing on the shaft to
produce rear wheel HP.
-----------------------------------------------------------------
Steven St.Laurent
Test Engineer
Test Branch, GSD,MCTSSA
MARCORSYSCOM, US Marine Corps
mailto:stlaurents@mctssa.usmc.mil (work)
mailto:Saint1958@home.com (home)
Office: (760) 725-2296
-----Original Message-----
From: Mike Schwall [mailto:mschwall@flash.net]
Sent: Thursday, February 03, 2000 12:06 PM
To: dakota-truck@buffnet.net
Subject: Re: DML: Drive shafts. Very weird.
At 11:01 AM 2/3/2000 -0600, you wrote:
>Hey Dester,
>
>Do you have a steel 2-PIECE driveshaft, with a CV boot type thing at the
>joint? If so, lookout! The boot has been known to grenade at speeds
>over 90 mph, and the one piece, NASCAR approved aluminum shaft is DC's
>fix. Anybody's head hurt yet? Here we go...
>
>The aluminum shaft may not provide any gain over the steel one - it's
>all about second moment or inertia, or how much energy it takes to "spin
>up" something. A shaft with a larger OD will take more energy to spin
>up to a certain RPM than a smaller one, given they are the same material
>and wall thickness. The larger shaft, if made of a light enough
>material may have an second moment equal to the smaller shaft of heavier
>material.
>
>So what I'm saying is that the larger diameter aluminum log may not free
>up horsies compared to the smaller diameter steel unit.
>
>Yah?
>Cale
>98cc318sporty
Wheels are turning.... I see your angle, but even if the aluminum is
thicker, it is still lighter than the stock steel. So the rotational mass
of the aluminum is still less than the smaller steel, so the force required
to overcome the inertia is still less, thus allowing more horses to go to
the rear end. Ever seen carbon fiber driveshafts. They have a large OD,
but they are extremely light and strong. Less rotational mass (weight),
less affect by inertia, less power wasted turning the driveshaft.
Mike
__________________________
mschwall@flash.net
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