COPY of cupexperience.com
Super clear explanation of the control system, thanks!
remains of the question what this all really means and what are the limits, just generating power by humans, which is then used by machinery/eklectronics to controll the beast (and next, to drive it?) Interesting question is when sailing stops and becomes motorsports ....AC72 foil control secrets
Some people have questioned whether Oracle Team USA had a secret (and illegal) foil control system in their AC72 that helped them defend the America's Cup.OTUSA has released drawings and photos of their system, which used a simple "mechanical feedback" loop to allow precise control of the daggerboard rake. Helmsman Jimmy Spithill had buttons on the wheel to rake the daggerboard fore and aft in precise increments of 0.5° giving him better control over lift for hydrofoiling.
OTUSA
designers Dimitri Despierres (mechanical systems) and Eduardo Aldaz
Carroll (electronic systems) began work in late June 2013 to help the
team gybe better. The goal was to reduce distance lost in a gybe from
150 meters to 30 meters. To do this the engineers needed to deal with
the problem that board movement varied depending on hydraulic pressure,
making it impossible to control lift. What they needed was a way to move
the board a fixed amount independent of the pressure and drag load on
the board. Within a month, mechanical engineer Alex Davis developed a
test bench with a servo control, hydraulic valve and hydraulic ram to
simulate movement of the daggerboard box (see photo below).
Once
the test bed system worked, the system was tested on board. Accuracy
was fine, but it reacted too slowly. Mechanical engineer Neil Wilkinson
and hydraulics specialist Rolf Engelberts improved the system to improve
response speed and make everything more reliable and robust.
AC72 daggerboard controls on OTUSA Boat 1
The
hydraulic ram for rake is not visible in the photo below, but you can
see the rams for board cant, as well as the daggerboard cage and
daggerboard box. The box moves within the cage, which is fixed in the
hull. Rendering
of AC72 daggerboard cage below. The cage is fixed in the hull. The
daggerboard box moves fore / aft (rake) within the daggerboard cage. The
daggerboard cage moves inboard / outboard (cant) within the hull. Controversy and protest by Team New ZealandOTUSA wanted to make sure their system complied with the AC72 Class Rule. They filed a "Public Inquiry"
to the Measurement Committee and got approval on 8 August 2013 - only a
month before the America's Cup Match was to begin. Team New Zealand
then tried to have OTUSA's system ruled illegal but the Measurement
Committee stood by their initial decision and the International Jury ruled
that New Zealand's protest was made too late, but would not have
succeeded even if it had been filed on time. The marked up schematic
below was part of Team New Zealand's submission. OTUSA eliminated the
spring labeled "Component X" making the TNZ protest moot.
