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exploring its mechanical design and some problems that were solved by early engineers and
some that were not. But irst, it is desirable to establish an important feature of nomencla-
ture, to avoid confusion in discussing the literature of the past and of the present.
Notice that we have used both the terms
windmill
and
wind turbine
in the preceding
overview. Modern technology has irmly and rightly established the
wind turbine
as the
prime mover of a wind machine capable of being harnessed for a number of different
applications, none of which are concerned with the milling of grain or other substances (at
least in industrialized countries), together with the various other pieces of apparatus
necessary for a complete power plant:
mechanical transmission, nacelle, tower, load (e.g.
generator or pump), control gear
,
and so forth. The wind turbine is also described as a
wind energy conversion system (WECS)
or, if used to produce electric power, as a
wind
turbine generator (WTG).
However, up to recent times the term
windmill
was used for the whole system,
whatever its duty, be it generating electricity, pumping water, sawing wood, or, as we shall
see a little later, pumping air for an organ. It seems that in nearly all previous writings,
windmill
is used, whether it is directed toward technological, historical, or simply
antiquarian aspects (or combinations of them). Since this chapter is concerned with past
events, it is convenient and has a certain logic in it to retain this term in its historic sense,
using such words as
wheel, rotor
,
or
blades
to refer to what we now call the
turbine
itself.
The adjectives
horizontal
or
vertical
attached to the two major classes of wind machine
are a potential source of misunderstanding. In modern terminology, they refer to the
geometrical aspect of the driving shaft on which the rotor (turbine wheel) is mounted. For
example, an oldtime wooden machine with four sails (a type typiied by the term
Dutch
windmill
)
is now called a
horizontal-axis wind turbine (HAWT).
Past usage terms it a
vertical windmill
,
because the path of a point on a moving blade lies in a vertical plane.
A machine built like a carousel with a central vertical axis and a number of straight or bent
vanes arranged in a direction more or less parallel to the shaft is today called a
vertical-axis
wind turbine (VAWT)
but in past times a
horizontal windmill.
This typology is emphasized
here because the new and old usages are diametrically opposed. To avoid confusion, the
modern terms
horizontal-axis windmill
and
vertical-axis windmill
will be used here,
although molinologists continue to study vertical and horizontal windmills.
The International Molinological Society (TIMS) was formed following a meeting in
Portugal in 1965 of savants and others interested in windmills. The word
molinology
was
introduced and oficially adopted at that time to deine the ield of studies concerned with
windmills, water mills, and animal-powered mills. The term is derived from the root
molino
found in differing national forms in many countries of the Western Hemisphere; it
can be combined with such Greek sufixes as
-ology, -graph, -phile
,
etc. It was proposed
to the philological authorities of every country for adoption into their vocabularies and
dictionaries. Since the irst gathering in 1965, meetings of TIMS have been held in 1969
(Denmark), 1973 (The Netherlands), 1977 (England), 1982 (France), 1985 (Belgium), 1989
(W. Germany), 1993 (Wales), 1997 (Hungary), 2000 (USA), 2004 (Portugal), and 2007
(Netherlands). The published transactions of these symposia are a most interesting and valu-
able source of current matters connected with the history, cataloging, and preservation of
windmills.
This chapter is aimed toward engineers and technology-minded readers and not toward
molinological scholars. Hence, the author has tried to steer a middle course with respect
to quoted sources by endeavoring to give proper credit for speciic material without
overloading the text with references of interest only to the history specialist. In addition,
he has leaned heavily on many of these sources for the general information as well as the
particular material contained in them, and he acknowledges this debt with gratitude.
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