Sideways airplane wing anyone???
This cat is designed to be ‘autonomous’ and sail on it’s own. They split this thing down the middle and gutted the front to put in a reinforced mast to hold the solid sails. They are controlled by hydraulics, and are split into an upper and lower section. Each half acts like a wing and aileron with the ‘aileron’ used to control the amount of ‘wing’ catching the wind.
You can see how big the mast is in this picture, and it is about that large all the way to the top. Also you can see the ‘probes’ on the gray spars that stick out to the right side of the wing. They are very sensitive instruments that give ‘relative wind’ indications and allow computer control of the wing position.
Strictly speaking wouldn’t that make the “ailerons” servo tabs?
Despite their large size and full span nature.
I want one.
Jon- You are correct, I just couldn’t think of the ‘right’ term last night… Thanks! 🙂
LL- I’ll see what they want for it. 😀
I think they are flaps rather than trim tabs. When actuated they would effectively give the wing camber on one side or
the other allowing it to generate lift. I like the idea of wingsails in theory, in practice I would hesitate to use
them on an open-ocean vessel other than a fully-crewed raceboat like the AC-72s.
I get that the rig is freely rotating and ought to feather, reducing lift and drag, but until you’ve been on a sailboat in a gale at sea you just don’t understand how wild things can get, and how fast wind direction can change. I’d like to be proven wrong. Interestingly, the rules for the massive AC-72s limited racing to winds under 22kt, a nice sailing breeze IMHO.
Amazing
Here’s what I found: http://www.harborwingtech.com/faq.htm
🙂
(I noticed the “X-2” on the stern and googled ‘X-2 airfoil catamaran’.
Old Surfer I think servo tab is more appropriate as they are being used to change the trim of the larger surface. This could be done directly but requires less energy through the use of the smaller servo tabs creating the rotational moment about the mast aerodynamically. That is if I understand NFO’s description of the operation of this yacht.
Once trimmed to a new angle to the wind then the sail assemblage would create a differently angled force vector. Flaps do create a rotational moment but their primary purpose is creating additional lift rather than change the direction of the lift vector itself.
Jonathan, According to the web page cited by Tam, we’re both wrong. The twin tails are also movable and they control the angle of attack. I thought they were passive weathervanes. The aft part of the foil is a “flap” however, in that it is used to control the camber of the wing as a whole. A servo tab is used to move a control surface, or assist it’s movement.
It’s an interesting rig, but it’s seaworthyness? I wonder, wing sails of this general type show up regularly, along with soft rigs that pivot freely as well, and none that I’m aware of have been proven offshore. I’ve been involved with multihulls since the early 60’s, and my boats designs have all had soft sails for reliability and safety reasons.
Incidentally, the boat pictured is a trimaran, not a cat.
All- Thanks! I’m ass deep in work and didn’t have time to do any research. Thanks to Tam and Old Surfer for the explanations!!!
Posted from my iPhone.