Boats and foils comparison

The Advocate

Super Anarchist
Rhino at USD 995 is way way beyond my budget, but I'll scout around for an alternative CAD app that can maybe do the same.  Thanks for outlining the procedure.  :)
The program that Rhino was developed from (I think) was free and available last time I looked. Buggered if I can remember the name of it though, haven't had it on the last few laptops.

 

Mozzy Sails

Super Anarchist
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The flap pivot rules were quite limiting. But even with those rules all teams ended up with surface pivot points. I'm not sure how much of that was just running out of time  / needing reliability. And the team with the most complex mechanisms within the wings were probably the slowest foils (or had most difficulty at low speed at least).

I still think one of the biggest things they could do to widen the wind range would be to open up the flap rules including deformation of main wing. But you'd probably have to slacken the CoG rule for the foils too, to allow those extra mechanisms in without bulking out too much. 

But, having said all that, ETNZ won by moving much of the mechanisms clear of the water and housing in the spat. It's probably that plus the ability of run the T at more extreme cant angles that made the biggest difference. 

 

MaxHugen

Super Anarchist
But, having said all that, ETNZ won by moving much of the mechanisms clear of the water and housing in the spat. It's probably that plus the ability of run the T at more extreme cant angles that made the biggest difference.
What mechanisms could they move?

I would have thought there wasn't much there, apart from the actuator(s) and a couple of hydraulic lines.

Ps: and some sensors I guess.

 
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Mozzy Sails

Super Anarchist
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What mechanisms could they move?

I would have thought there wasn't much there, apart from the actuator(s) and a couple of hydraulic lines.
Hydraulics / electronics actuators. I presume that is why they have the access window to the spat.

LR has an access window a little lower (covered by tape in some photos or seen with water dribbling out).

INEOS had mechanisms within the foil, and you could see they were deconstructing the wing itself fairly regularly by the way the screw holes were covered and re-fared (possibly screw drive or something).

 

MaxHugen

Super Anarchist
Hydraulics / electronics actuators. I presume that is why they have the access window to the spat.

LR has an access window a little lower (covered by tape in some photos or seen with water dribbling out).

INEOS had mechanisms within the foil, and you could see they were deconstructing the wing itself fairly regularly by the way the screw holes were covered and re-fared (possibly screw drive or something).
OK, I thought they would be using hydraulic actuators.

Getting leverage from an actuator, down from the spat, through the "boot" (part of the foil assembly), and to the foil sounds complicated.

I would have guessed that hydraulic line connections would perhaps be in the spat area.

But we may never know!

 

MaxHugen

Super Anarchist
I would have thought the sensors would be further upstream.
Guessing as always, but they may have had pressure sensors on the foil wings? Would be very useful for the designers to get data on when the foil was approaching - or lower than - the water vapour pressure, resulting in cavitation.

Possibly one for the actuator(s) as well, to ensure they had correct pressure there.

 

Mozzy Sails

Super Anarchist
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United Kingdom
Sensors I think go down all the way out along the wing span. 

I'm not certain what ETNZ used in the end, as with the last set of foils they had distinctly split flaps rather than the connecting piece which was part of the control system. 

However... if you want to use only one actuator to control two control surfaces (each flap counts as a single control surface), then it has to be done electronically. 

22.7 A hydraulic actuator within an HCC may only be mechanically connected to one control surface.

24.2 Only the following electric actuators permitted within an ECC:
(d) actuators used to rotate or twist the foil flaps;

 

The Advocate

Super Anarchist
Guessing as always, but they may have had pressure sensors on the foil wings? Would be very useful for the designers to get data on when the foil was approaching - or lower than - the water vapour pressure, resulting in cavitation.

Possibly one for the actuator(s) as well, to ensure they had correct pressure there.
Couldn't they be in the boat though?

 




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