Starboard fuselages and stability

What's the difference in flight stability between the old 95+ and 115+ fuses? I have the 2021 GT-R+ setup (95+, 800, 85 cm carbon mast) with a 255-2 tail wing. As the chop grows, I have some problems maintaining level flight, which I don't have nearly as much with the SuperCruiser fuselage and the 1300 wave front wing (in the front 2 holes, with the corresponding stab).

I assume a 95 cm mast would help, but spending $1400 or $1900 for the C400 is out of my budget, so I'm looking at other options. I recall some comments that the longer fuse would help reduce dolphin rides. Getting a larger front wing is also an option, although it's a bit questionable if I want to put more money into the old fuse.

I'm well aware of the angle benefits of the larger fuse, but they don't matter much, since I'm not racing and the angles I'm currently getting are good enough.

Might sound a little crazy, but if all you want is ride stability and you're not too worried about upwind angles, I'd be trying to get one of the old black 115 fuses. The 115+ would improve the situation for you, but the mast to fuse join ends up being more central on the fuse, which makes for a less stable ride than a fuse with more tail and a less forward front wing.

You'll definitely get a more stable ride with a longer fuse though. I was surprised how much slower the pitch happened when I got on a longer fuse, compared to a short old school one. It was night and day.

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tswei99 said..

Subsonic said..
Might sound a little crazy, but if all you want is ride stability and you're not too worried about upwind angles, I'd be trying to get one of the old black 115 fuses. The 115+ would improve the situation for you, but the mast to fuse join ends up being more central on the fuse, which makes for a less stable ride than a fuse with more tail and a less forward front wing.

You'll definitely get a more stable ride with a longer fuse though. I was surprised how much slower the pitch happened when I got on a longer fuse, compared to a short old school one. It was night and day.

Fully agree w/. Subsonic here. The 115 "black" is a classic, and I believe a lot of PWA riders keep one in their quiver for this reason. I have both the 115 and the 115+ and for across the wind really pushing speed, I prefer the 115.

And, according to my dealer, this geometry is so popular that Starboard kept it in the the new upgraded Evolution designs. There is a fuse called "115 Classic" that retains the original 115 geometry.

Every 10 cm in fuse length makes a BIG difference in stability, but there is a point where the wing is too far forward for cross-wind sailing. For a budget friendly option, you could also find a used 105+ fuse to make your ride more stable. This fuse also gives you the shims in the tail to fine tune.

Yeah, the 115 black may be the cheapest option if he can find one. However, he can't go to Evo fuses without getting a new front wing unfortunately. So either 115 black or 105+.


Oh also does the 115 black not have a shim? I wonder if that means he would have to do something with the tail wing since he has a -2?

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boardsurfr said..
Thanks for all the feedback. The used market for Starboard foil components in the US seems to be somewhere between very small and non-existing, and "the" SB foil dealer does not have the original 115 in stock. So it's between the 105+ and 115+, or switching to the Evo fuselage. I realize that I'd have to buy a new front with when switching to Evo, but I could possibly sell my SuperCruiser setup and get a couple of evo front wings from the proceeds plus the $300 I'd have to spend on the new plus fuse. Does that make sense?

Yeah your options seem to be:

115 black fuse (if you can find it), may need a different shim to work with the 225-2 rear
105+ fuse (with your current other wings
115+ but it's going to put the foil lift way more to the front

105 Evo
115 Classic Evo
115 Evo (same power issue as 115+)

I don't know enough to say whether the 115 Classic Evo or 105 Evo would be better for you or not. A lot of other brands seem to be closer to 100-105cm lengths for slalom (vs longer for course racing), but they likely measure them slightly differently.

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boardsurfr said..
Currently thinking about a switch to the Evo fuse (probably the 105+) with a front wing that's larger than the 800. Does anyone have experience with the 1000 and 1100 front wings, and how they compare to the 800? I was quite impressed with Sam Ross pushing the FR1100 quite easily to 26 knots .. but that could reflect skill more than foil characteristics.

What sail sizes and wind conditions are you intending to use the 1000 wing in? I always felt the C300 mast was too soft to really be pushed with the 115+ and 1000 wing (albeit on a 9.0). Especially when going deeper upwind or downwind, I would feel the back foot mysteriously wobble when flying through chop. It was jarring enough that I'd turn my head and look down at my feet while in flight. The 800 wing and 115+ fuse never felt unstable on the C300 mast.

The C400/C600 mast will feel 'easier' to use in all conditions, straight out of the box. It's quite a noticeable difference!

You'll go a bit slower than normal on any longer fuselage compared to what you're used to on the 95+

As for Sam Ross pushing 26 knots on the FR1100... Most people I know who own the 800 wing have barely come close to that speed, so I wouldn't have my hopes set on breaking speed records with the 1100 if you get it

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Niichts said..
As for Sam Ross pushing 26 knots on the FR1100... Most people I know who own the 800 wing have barely come close to that speed, so I wouldn't have my hopes set on breaking speed records with the 1100 if you get it

I don't think I'll every break any speed records on the foil. But I'd love to know how the 1100 compares to the 800 for others that may be closer to my limited skills than Sam Ross. In the Sam Ross videos, it was not so much that he reached 26 knots - it was the apparent easy of getting there, while talking into his headset all calm and relaxed, and not he least bit out of breath. Very different from me getting to 20 knots on the 800!

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boardsurfr said..

Niichts said..
What sail sizes and wind conditions are you intending to use the 1000 wing in? I always felt the C300 mast was too soft to really be pushed with the 115+ and 1000 wing (albeit on a 9.0). Especially when going deeper upwind or downwind, I would feel the back foot mysteriously wobble when flying through chop. It was jarring enough that I'd turn my head and look down at my feet while in flight. The 800 wing and 115+ fuse never felt unstable on the C300 mast.

I'm thinking about the 1000 or 1100 for lighter conditions (under 13 knots average on iWindsurf meters, which is about 11 knots measured on shore). Above that, I have no problems flying on the 800, without having to pump like crazy.

I'm nowhere close to pushing the limits on the foil. I have felt the wobble you mention on alu masts when pushing my (low) limits a bit, but never with the 85 cm carbon mast I have. I'm usually on a 7.0 Severne Foil Glide 2. I got 7.8 and 8.5 sails with 2-3 cams that I have also used on very rare occasions, but the Foil Glide is so light and easy to pump that I usually don't bother.

I have both the 800 & 1000 Millennium front wings and I find the 1000 is a big jump in terms of early flying. It still has an impressive top end, but is much harder to jibe than the 800, it takes a more deliberate and gradual turn-in.

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Niichts said..

What sail sizes and wind conditions are you intending to use the 1000 wing in? I always felt the C300 mast was too soft to really be pushed with the 115+ and 1000 wing (albeit on a 9.0). Especially when going deeper upwind or downwind, I would feel the back foot mysteriously wobble when flying through chop. It was jarring enough that I'd turn my head and look down at my feet while in flight. The 800 wing and 115+ fuse never felt unstable on the C300 mast.

The C400/C600 mast will feel 'easier' to use in all conditions, straight out of the box. It's quite a noticeable difference!

Completely agree that a large wing and long fuse combo (115+/1000 in your example) really call for a stiffer mast than the C300, even on 7.0 (biggest sail I foil on).

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WindFlyer said..
* The 115 black neither requires nor takes any shims; the stab mounts directly. One can choose a "zero" or "minus 2" stab.

But the 115 black takes the same stabilizers as the plus system, right?

A couple of degrees between the stabs seems like quite a large jump, though. I found that even a change of 0.5 degrees can make quite a difference.

I have the 115+ and the 95+ and honestly never use the 95+ Because it's not nearly as stable (pitch control) as the 115+. For freeriding/freeracing I find the 115+ better. I also have the 800 and 1000 wings. The 1000 gives you that little extra lift for those very light winds and allows you to pint upwind very well. I don't find it to be a hard wind for jibing unless you are in very light wind and are using a big sail (I don't think the problem is the wing, the problem is experience and apparent wind backwinding the sail). In my experience the 115+ will make your flights much more stable

starboard will keep selling the original plus fuselages for a while (at least the 115+ and 95+ because they are part of the Olympic setup).
yes, the black fuse takes the same stabs but you cannot use shims (as you/others pointed out) and that is one of the reasons I decided to get the 105+ Instead (which I haven't been able to use yet).

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boardsurfr said..
There seems to be total agreement that the 105 and 115 fuses make stable flights a lot easier. What surprises me a bit is that with the Slingshot Infinity and Starboard Supercruiser setups, a fuse that's comparable to the 95+ in length is perfectly adequate for stable flights. Is this because of the larger front wings and stabs used with the Infinities and Supercruiser setups? For both, I liked the 1300 wings best, but those are still a lot bigger than the 800s. Or is there something else?

I think it's because the low aspect and delta shape makes it less sensitive to angle of attack changes. And slowwe speeds. The fat rear wings keep it from being sensitive. High aspect wings with no sweep are much more sensitive to angle of attack.

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boardsurfr said..

aeroegnr said..
I think it's because the low aspect and delta shape makes it less sensitive to angle of attack changes. And slowwe speeds. The fat rear wings keep it from being sensitive. High aspect wings with no sweep are much more sensitive to angle of attack.

That seems to make sense, but I'm not sure that angle of attack is a big factor. I have not found any graphs that compare lift vs AOA curves for different profiles.

Speed could theoretically be an issue, but I doubt it's a big factor in my case. My typical speed on the 1300 is just 2 knots slower than on the 800, perhaps a bit more than 10%. On either wing, I'm far enough above the stall speed that instabilities near stall don't come into play.

I'm thinking this might be more something like simple resistance, like pushing a plate into water. A bigger plate will have more resistance, which is probably +- linear with plate size.

There's some inertia effect too but yes it stretches out the lift curve so it takes more angle to get the same lift. So you end up having more margin for error and small movements affect it less. I'd have to go back to some old books and look up some stuff to get real numbers but longer fuses overcome it.

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aeroegnr said..

I think it's because the low aspect and delta shape makes it less sensitive to angle of attack changes. And slowwe speeds. The fat rear wings keep it from being sensitive. High aspect wings with no sweep are much more sensitive to angle of attack.

Not in position to comment on the theory... But going from experience, you may be on to something here.

For what it's worth, the 1100FR wing has some good sweep to it (which I supposes contributes to its comfort factor).

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aeroegnr said..

boardsurfr said..

aeroegnr said..
I think it's because the low aspect and delta shape makes it less sensitive to angle of attack changes. And slowwe speeds. The fat rear wings keep it from being sensitive. High aspect wings with no sweep are much more sensitive to angle of attack.

That seems to make sense, but I'm not sure that angle of attack is a big factor. I have not found any graphs that compare lift vs AOA curves for different profiles.

Speed could theoretically be an issue, but I doubt it's a big factor in my case. My typical speed on the 1300 is just 2 knots slower than on the 800, perhaps a bit more than 10%. On either wing, I'm far enough above the stall speed that instabilities near stall don't come into play.

I'm thinking this might be more something like simple resistance, like pushing a plate into water. A bigger plate will have more resistance, which is probably +- linear with plate size.

There's some inertia effect too but yes it stretches out the lift curve so it takes more angle to get the same lift. So you end up having more margin for error and small movements affect it less. I'd have to go back to some old books and look up some stuff to get real numbers but longer fuses overcome it.

Interesting. Armstrong has a tail wing that has a very pronounced sweep angle, the Flying V Tail Wing. Some lighter wingers absolutely love it, while heavier wingers consider if worse than straight wings or even unusable. Seems it does not "stabilize" enough for the heavier wingers, which the curves above show.

But the Flying V tail is an extreme example. Low aspect foils have much more moderate sweep angles at quarter chord (which seems to be where the angle is typically measured). At those lower angles, the effect on lift would only be moderated. But the data are usually for airplane wings, which have the same sweep angle over the entire length. Low aspect foil wings are often rounded off, so they have increased sweep angles towards the tip. I'd expect more sweep towards the tip to lead to less steep curves.

I also did find a lift vs. aspect ratio graph in a publication at www.researchgate.net/publication/281148227_Aerospace_Vehicle_Design_Regional_Jet_Transport_-_An_Aerodynamics_Perspective :



It's the same effect as the sweep back: a steeper curve for higher aspect ratios. The direct comparison of the 800 and 1300 show both the higher aspect ratio and the lower sweep angle for the 1300:



So the combined effect of higher aspect and less sweep means that higher aspect foils are a lot more sensitive to angle changes, and therefore changes in foot and mast foot pressure. So I obviously need a longer fuse for the 800 to get similar similar stability in chop.

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Niichts said..

FWIW, I did not like the feeling of the 1000/115+ on my 85cm SB foil freeride board at certain points of sail, but it felt mostly fine on the 91cm slalom.

I'd concur with this.

I also felt that the 1000 is most at home with boards on the wider end of things (happier on the 91cm SB foil 177 than on the 85ish freeride/freerace boards).

Had my first session on the SB 1100 freeride front wing with the Evo 105 fuse and 225/-2 stab today, and loved it. Surprisingly, the distance from stab to the tip of the front wing is only 3 cm longer than for the 2021 SuperCruiser fuselage with a 1300 wave wing mounted to the front holes. But the front wing is moved forward about 9 cm, and since it's higher aspect, the center of lift is moved forward more than 10 cm. I think the advice from North Beach Windsurfing to not get the 115 fuse with the freeride wing was spot on - another 10 cm forward would have been too much.

It was flat (off shore wind) today, and gusts were 18-25 mph, so it remains to be seen how this combo feels when it gets choppy and windier. First impression from a bit of boat chop, though, was that the wing is much less affected by the chop than larger wings. This setup feels like the right mix of speed, excitement, control, and ease of use for me. Can't wait to try it on a typical choppy and windy day.

Thanks to everyone for the advice in helping to pick this combo.