AMERICA'S CUP - AC72:
THE FOUR WINGS
One would
expect that the aerodynamic teams of the three syndicates, Oracle Team USA (defender),
Emirates Team New Zealand and Artemis Racing (challengers) would produce rather
similar wings. Yet such is not the case! To the contrary, it appears that the options
are very different from each other, proof that individual scientists’ personality
and experience produce unique solutions…
The
wingsail of Oracle is a model of its kind: simplicity, soft forms, steerable
trailing edge on the leading edge flap with a thick profile, more flexibility
of the four vertical panels of the trailing edge flap with a thin profile.
The power
will be there, and the team had difficulties to manage righting moment and
unexpected movements in sudden strong wind
ETNZ one is
in its pure form. A straight-line leading
edge, two flexible flaps in plan; the leading edge element is thicker than the
one of the trailing edge, which is vertically divided in four panels. The center
of pressure is lower than the Oracle and Artemis
wings, and a slight complementary surface on the lower flap. The entire system guarantees an amount of
power, which was properly handled from the very first sea trials, the catamaran
displaying a stable flight attitude on one foil.
The first Artemis
wing is more elaborate, with sinuous curves, divided in three elements. The
first element is very large and shows a lenticular profile. The second and
third flaps, with thinner profiles, are divided vertically into six panels;
combined, the three elements resemble the wings of long-haul aircraft with
flaps extended.
The second Artemis wing is intended to support simplicity: it is divided in two elements, and it preserves curves on the leading and trailing edges. The first flap has a thick leading edge profile; the second one is very thin and can be moved from the first one.
The second Artemis wing is intended to support simplicity: it is divided in two elements, and it preserves curves on the leading and trailing edges. The first flap has a thick leading edge profile; the second one is very thin and can be moved from the first one.
On the construction
side we can see the same range of differences. The frame structure of Oracle
wing is 0.64 meter long (2’1’’); it is 0.78 m (2’6’’) long on ETNZ, 1.05 m
(3’6’’) long on Artemis I and 1,20 m (4') on Artemis II.
This analysis reflects
that the power of the three wings is certainly not the same and each profile is
quite unique at various points of sail.
François and Jacques wish to thank Robert and Greg (CupInfo) for their assistance in the translation in English.
Their link: http://www.cupinfo.com
