enigmatically2
Super Anarchist
It did. In a fair amount of waves too. This is where it gets impossible to compare performance between boats in different conditions. Seagulls or no seagulls.
INEOS Team GB
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The_Alchemist
Super Anarchist
As enigmatically2 says, it is really hard to tell.
Basically, if these boats are out of the water and foiling they look like they are ripping along...
dogwatch
Super Anarchist
Calling Jonathan Livingstone.........
enigmatically2
Super Anarchist
Which is why anyone saying any team is fastest at this point given different winds, waves, test strategies, points of sail etc is talking utter gobshite.
But then some of our members could pool their brain cells and still not challenge a goldfish intellectually
olo.0815
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Am I the only one not able to find the T6 Day 28 recon video? Supposedly it was a good session, if I'm not mixing up statements... @Mozzy Sails: anything on the recon cloud?
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I don't see a Day 28 but here's Day 29
Minimising downtime in an America’s Cup programme is a golden elixir, rarely achieved but always strived for and with such technically advanced boats being built, re-built, tested, and modified, the gremlins do, on occasion, creep in. For INEOS Britannia it was just one of those days after a scintillating foil data session on Tuesday, with sunshine and a perfect 6-10 knot breeze that looked set to build into the late afternoon, greeting the sailors on Wednesday.
Speaking afterwards, Jeff Causey the Shore Team Manager for INEOS Britannia was understandably giving few specifics away but put the situation in perspective saying: “We've just come out of the shed from being through this upgrade period for last few weeks so there's quite a lot of new kit on the boat and some of the new bits that we’re trying out didn't work as well today as we would have liked and that's part of what we're doing out there, so short day for us."
The_Alchemist
Super Anarchist
Mozzy Sails
Super Anarchist
Day 28 is on the recon portal. Interview with Dylan. Looked a decent enough day.
robingimblett
Member
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With the risk of waves it seems counter intuitive to have the most beneficial lifting section closer to the surface at greater risk of breaching. The W has shorter leading edge length / total length of coloured lines.
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BA said something in a recent video when addressing a question about the W, something about there being 'a tradeoff between the higher junction point and the cant angle.'
JALhazmat
Super Anarchist
That’s all assuming you have the exact geometry..
there will be less leeway on the W foil as you have shown it also
given the bulb height it’s very unlikely both woukd run the same can’t angle
Nauti Buoy
Member
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Watching the Australian Grand Prix, noticed someone who looked like a former Ratcliffe employee in the Merc garage.
Anyone else recognize him? Or am I seeing things?
JALhazmat
Super Anarchist
Who do you think you are seeing? It’s not Nick Holroyd
robingimblett
Member
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Accepting that there are many variables, it's still interesting to push around a few simplistic permutations for comparison.
If 64 degrees were the optimum cant angle for flat water the W foil produces more windward lateral force than the curved foil, as expected. If the cant angle drops to 57 degrees to account for some wave height, the W foil still produces more windward lateral but it's advantage over the curved foil has diminished.
The leading edge length is shorter for the W foil so potentially less drag AND it has less central fin length, which contributes no adjustable force only mass.
If 64 degrees were the optimum cant angle for flat water the W foil produces more windward lateral force than the curved foil, as expected. If the cant angle drops to 57 degrees to account for some wave height, the W foil still produces more windward lateral but it's advantage over the curved foil has diminished.
The leading edge length is shorter for the W foil so potentially less drag AND it has less central fin length, which contributes no adjustable force only mass.
olo.0815
New member
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I fully agree with the concept of looking at special cases to learn about trade-offs!
Two thoughts/questions to add:
1) Do we know whether the W-foil's outer section is parallel to the bottom of the rule-box or whether it tilts upwards? There was a lot of talk about the angle at which the foil intersects the surface, but for your cases there's hardly a difference (assuming same cant angles - which might be a bad assumption...).
2) Is it allowed to actuate the inboard and outboard sections of a foil flap differently, or is there a symmetry requirement I've overlooked in the rules? That would allow to tune the ratio of lift vs. upwind force which could be cool.
Two thoughts/questions to add:
1) Do we know whether the W-foil's outer section is parallel to the bottom of the rule-box or whether it tilts upwards? There was a lot of talk about the angle at which the foil intersects the surface, but for your cases there's hardly a difference (assuming same cant angles - which might be a bad assumption...).
2) Is it allowed to actuate the inboard and outboard sections of a foil flap differently, or is there a symmetry requirement I've overlooked in the rules? That would allow to tune the ratio of lift vs. upwind force which could be cool.
enigmatically2
Super Anarchist
olo.0815
New member
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Tell me if I'm mistaken (or this has been discussed) but that option with a W-foil sounds like an awesome tool for moding without any need to change cant:
High & slow - maximum flaps.
High and progressively faster - reduce flaps on 'horizontal bits' first.
Max speed - no inner flaps, use wing-tip flap(s) for fine control.
High & slow - maximum flaps.
High and progressively faster - reduce flaps on 'horizontal bits' first.
Max speed - no inner flaps, use wing-tip flap(s) for fine control.
The_Alchemist
Super Anarchist
I would assume the optimum cant angle to be greater than 64 degs since most of the boats tend to have a portion of the foil tips out of the water.
Mozzy Sails
Super Anarchist
Not got any great head on shots yet, but the outer segments (small tip excluded) look parallel to bottom of the box / inline with one another.
We might get an idea to whether they think they will need those external actuator pods or not by looking at whether they sit within the box or outside. If they were a feature on the final race foils, they would have to be inside the box, thus raising the lifting surface by their depth. But if they're just a stop gap measure, then INEOS might have made them outside the box.
Just to clarify, the wing, including flap and actuators has to sit inside the box across it's range of flap angles. I therefore doubt the leading edge of any foil is quite on the bottom of the rule as it has to allow for flap movement below the leading edge.
Now each flap segment doesn't have to be linked they can really play with individual flap segment angle. Meaning they can really play with the rations of vertical to horizontal lift as shown in @robingimblett post.
The downside, as covered a lot, is you need four actuators, which take up volume below the water (versus ETNZ housing one actuator in the foil arm). Plus a slight reduction in righting moment (although perhaps this could be equalised with use of flaps).
We might get an idea to whether they think they will need those external actuator pods or not by looking at whether they sit within the box or outside. If they were a feature on the final race foils, they would have to be inside the box, thus raising the lifting surface by their depth. But if they're just a stop gap measure, then INEOS might have made them outside the box.
Just to clarify, the wing, including flap and actuators has to sit inside the box across it's range of flap angles. I therefore doubt the leading edge of any foil is quite on the bottom of the rule as it has to allow for flap movement below the leading edge.
Now each flap segment doesn't have to be linked they can really play with individual flap segment angle. Meaning they can really play with the rations of vertical to horizontal lift as shown in @robingimblett post.
The downside, as covered a lot, is you need four actuators, which take up volume below the water (versus ETNZ housing one actuator in the foil arm). Plus a slight reduction in righting moment (although perhaps this could be equalised with use of flaps).
