Re: 4KQ Feulishness

[Andrew Duane USG/PE <duane@zk3.dec.com>]

Hairy green toads from Mars made mike tipton say:

> A quattro, weighing more, should get less milage.

I'd like to add an interesting note here.

About 2 years ago, Scientific American had a great article on 
the future of fuel economy in cars/trucks/etc.

One of the little things they mentioned is that AWD can actually
save fuel, by reducing hysteresis drag. This is the drag of the
tires deforming on the pavement, and is proportional to the fourth
power of the power being applied to the tire. At highway speed,
this accounts for a noticable percentage of total drag.

Doubling the number of drive wheels halves the power applied to
each wheel, which cuts the drag to one sixteenth. Of course, with
twice as many wheels, this translates to one eighth the drag.

I believe this is why quattros do lower around town, but the
same or better on the highway.

-- 

Andrew L. Duane (JOT-7)			duane@zk3.dec.com
Digital Equipment Corporation		(603)-881-1294
110 Spit Brook Road
M/S ZKO3-3/U14
Nashua, NH    03062-2698

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