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From: mrh@cybvax0.UUCP (Mike Huybensz)
Newsgroups: net.origins
Subject: Re: The Mathematics of Powerlifting and the case of the Ultrasaur
Message-ID: <725@cybvax0.UUCP>
Date: Thu, 5-Sep-85 11:20:51 EDT
Article-I.D.: cybvax0.725
Posted: Thu Sep  5 11:20:51 1985
Date-Received: Sat, 7-Sep-85 06:12:10 EDT
References: <387@imsvax.UUCP>
Reply-To: mrh@cybvax0.UUCP (Mike Huybensz)
Organization: Cybermation, Inc., Cambridge, MA
Lines: 41
Summary: 

In article <387@imsvax.UUCP> ted@imsvax.UUCP (Ted Holden) writes:
>      Sixty inches  is five feet;  the ultrasaur would need thighs
> slightly over ten feet in diameter  to have  any hope  of lifting
> his own body off the ground!  Of course, the fudge factors in the
> equation heavily favor the  ultrasaur.  A  realistic figure might
> be more like eleven or eleven and a half feet.
> 
>      Of course, the books do not show the ultrasaur with legs ten
> feet in diameter;   that would  make for  a funny  looking animal
> indeed, with  legs greater  in diameter than in length...
>
>      The Avon Field Guide to Dinosaurs  shows the  ultrasaur with
> legs about  four feet  in diameter, judging from the human figure
> which is in the picture for  scale; about  what you  would expect
> from a  normal feel  for animal  bodies and certainly the way any
> artist familiar with animals  would draw  him....

Ted, your calculations and observations include a number of fundamental
errors.

First, extrapolation of human strength to heavy-bodied quadruped dinosaurs
does not take into account the fact that the mechanical advantages of the
differently proportioned limbs are quite different.  Differing muscle
attachment points would give the dinosaurs' muscles much greater leverage,
perhaps several times more.

Your observations from imaginative drawings in books are also wildly
inaccurate: your "ten foot diameter" legs should be measured in the upper
thigh, which in most modern quadrupeds is well above the belly.  I'm
sure you would also disprove horses and elephants by their small leg
cross-section below the belly.  In addition, quadrupods seldom have a
circular thigh cross section, else they would bulge in the way you claim
the ultrasaur should.

As others have mentioned, please check original research literature, rather
than popular books.  That's where the science is: popular books are usually
pale reflections, drained of details and facts that won't sell to
scientific illiterates.
-- 

Mike Huybensz		...decvax!genrad!mit-eddie!cybvax0!mrh