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Subject:Re: On Fuel Economy - Some Teutonic Observations
From:John Rodgers
Date:Thu, 9 Aug 2001 10:32:35 -0500

Frank Grunthaner wrote:

>  I thought I would share two very interesting data sets with the list. At
> issue are the very detailed fuel consumption maps done for and submitted to
> the German Government for fuel consumption certification.
>

Frank, your comments in your Teutonic Observation post were very interesting.
Particular regards to difference in performance in operation of the Westy's by
Hubert Schmuk and Lenny Milquetoast.

Somewhere back in my ancient past, I studied aviation related aerodynamics and
seem to recall some references to relationships between, lift, drag, speed,
power, and fuel consumption. Where airplanes are concerned Increasing speed
increases lift increasing drag increasing power requirements increasing fuel
needs to produce more power to ovwer come that induced drag and in short order
the whole thing goes to hell in a handbasket.

In Aviation mechanic school and Pilot school, we were taught that in theory, one
could fly a barn door if one put a big enough engine on it.

In the case of our beloved Vanagon based vehicles, we are trying to fly that barn
door, but broad side forward. And in noting your expression of a thirty percent
increase in consumption by doing 80 vs 55 I think the relationsips expressed
above are proved out. In fact it would appear the plot of speed vs fuel
consumption for the Vanagon would be a parabolic curve. So for high speed it's
not  an even trade-off of extra fuel for extra speed. Speed gains are going to
suffer as fuel consumption over-runs the mark, so to speak.

Again, you have presented the list with some very interesting stuff!!

Thanks,

John Rodgers
88 GL Driver