The stab on my AFS W95 foil was not even close to being 90 degrees to the mast, and while the F1080 wing was at 90 degrees to the mast, the F770 and S670 wings were not. Initially I used clear tape of different thicknesses to get wings and stab at 90 degrees to mast, BUT over time the glue squeezed out and they went out of alignment. So used a piece of hard plastic to shim the stab, but finding the right thickness was just not possible, with the plastic shim aligned with centerline of the stab. Then I realized if I trimmed the shim away from the centerline using a piece of plastic that was a little too thick, I could fine tune the shim to get the stab to be 90 degrees to the mast. But because stab shim was not on centerline it was not easy to eyeball where it should be when I removed screws to clean and lube. So now I just remove 1 screw, clean and lube, with other screw still tight, and that keeps the stab aligned to mast.

For the wings I ended up using stainless steel tape, with a short piece of clear tape on each end to hold it in place, F1080 was perfect, F770 wing needed 1 layer of ss tape, S670 wing needed 3 layers of ss tape (only one went to centerline, other 2 trimmed back). Now everything stays at 90 degrees to mast. I can feel the difference when wings are aligned, just a really smooth feeling in the water, and really helps in getting up when on the low end wind range for a wing/sail combination.

Put foil on a flat table, wing tips will naturally touch the table since they are wider than stab, then tapped stab on both sides to hear it there is a gap between it and table, adjusted wing shims as needed. Can rotate foil 180 degrees to check that table is flat.

The newest AFS windfoils with 95/105 masts have wider wing and stab mounting areas on the fuselage, but the current foil with 85 cm mast is the same as the W95 shown here because they use the same wings/stab.

Have seen two brand new Axis foils with stabs that were not aligned with the wing, and those have machined aluminum fuselages, so it it hard to get everything aligned.

Used a caliper to confirm mast is aligned with upright level (looks a little off in picture).


Stainless steel tape side shim on F770 wing.

When I first got my AFS-2 in 2017, the wings (F700 and F800--old names) were 90 deg normal to the mast, but the stab was not.

I ended up sanding the cradle on the stab until it was 90 deg normal to the mast, or parallel to the wings.

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segler said..
When I first got my AFS-2 in 2017, the wings (F700 and F800--old names) were 90 deg normal to the mast, but the stab was not.

I ended up sanding the cradle on the stab until it was 90 deg normal to the mast, or parallel to the wings.

How did you determine that the wings were 90 degrees to the mast?

I did sand a little, but it was so far off, like one stab tip was 22 mm higher than the other, that I decided to shim instead. Plus there is just not much there in terms of width so easy to the change the angle of the stab front to back (angle of attack) by accident.

Using the above method you can get the stab aligned exactly with the wing, as long as the wing tips were not damaged and the table is flat.

And you can eliminate the table flatness as an issue by putting a level under the wing tips, and a second to lay the stab on, and then using small shims to make both levels level (the backs of wing and stab do not need to be on the same plane, just close)..

Update, you can get the stab and wing very close in alignment using the above and tapping each side of the stab, but the weight of the mast/fuselage will bend the stab a little making it appear to be aligned. What I now do is after tapping both sides of the stab to get it close, I then slightly lift each stab tip to see if it takes an equal amount of effort. If the effort is not equal I then adjust shim in/out until it is equal.

Then if you sight down the fuselage and move your head downward the stab left and right wing tips will protrude the same amount below the wing, see below pic where they stab tips protrude "about" the same amount.

Make sure everything is dry before shimming, and carefully assemble since it is easy for shim to move.

Decided to make a stab side shim out of ss tape (to replace plastic shim), like I used on the wings, and then tape the side shim to the stab instead of having it loose on the fuselage. Then checked stab alignment with all three wings by sighting down the fuselage (above) and levels on the table ( below). By elevating the stab using 2 levels I got most (but not all) of the mast/fuselage weight off of it so stab was not flexed as much by the weight, then when I lifted and lowered the stab by the tips I could hear and feel if both sides touched the level at the same time. The readings I got doing that were the same as with the sighting method. I used clear packing tape on the ends on all the ss tape shims to hold them in place, did not put across the middle because the glue will get squeezed out over time changing the shim thickness a little. The table/level method uses the bottom-side of the stab and wing tips to determine level, while the sighting method uses the stab tips and wing topside to determine level.

So I decided to re-align the stab. on my AFS W95 foil to be 90 degrees to the mast, and then re-aligned my 3 wings (F1080/F800, F770/F700, S670/F700S) to be parallel to the stab.

First I aligned the stab. to the mast by putting the fuse. in a vice with pipe jaws (protected fuse with rubber and 1/8" plastic) so the top of the mast pointed towards the floor, I then used a string taped to the back edge of the mast close to the fuse. with a weight on the end (fishing lead weight that hung into a cup of water on the floor to dampen the swinging) to get the mast perfectly vertical and then tightened the vise. I then mounted the stab. with a plastic side shim taped to it and adjusted until it was perfectly level using a 36" bubble level.

Next I used the table leveling technique (see above) to side shim each wing to be as close to parallel with the stab. as possible. And here is the interesting part, the F1080 and F770 wings both needed about the same amount of side shimming to be parallel with the stab. "on the same side that the stab. was side shimmed". BUT the S670 wing did not need any side shimming to be parallel to the stab. and at 90 degrees to the mast! That makes me think that the saddles on the fuselage were good, and the problem was the saddles on the stab. and F1080 and F770 wings were not level side to side.

The next problem is when I put an AFS carbon front stab. shim in it made the stab. go out of alignment (increased side shim effect), so I will have to make a different stab. side shim for use with the AFS front stab. shim. For now I am going to try the foil without a front stab. shim and see how it performs. I was convinced 1 front stab. shim was needed back in the early days "before" I realized the stab. and wings needed side shimming. My technique is improved and the mast/stab./wings are now all aligned, so maybe I will not need the stab. to be shimmed in the front since while it will increase lift it will also increase drag and so reduce speed. Will get back after next session.

After I was done side shimming the wings, went back to bench vise and re-checked stab. alignment again was still good, also used a tape measurer to see if distance from both stab. wing tips to mast head were them same, they were.

So I have done the side shimming several times now with different results. The difference this time was:
1) I used water to dampen swinging of the weight on the end of the line to get mast pefectly vertical so I could align stab. 90 degrees to mast,
2) and then when using the table alignment method (see above) instead of feeling, or listening to, the stab. left or right side touch the level I sighted down the fuselage, while holding fuse. by end, got a much more accurate reading that way. The stab. left and right sides flex remarkably easily for the first 1/8"-1/4".

Got out today with the AFS W95 foil and F1080 wing, forgot I did not have a stab. shim in and got up easily, even got all the way around in the air on a gybe, on a gusty day. I was surprised I just kept gliding around the gybe, so looks like no stab. shim is better when the mast/stab./wing are aligned.

Could not help rechecking the alignment, the F1080 and F770 wings were almost perfectly level with the stab. as I remembered, but tried putting a piece of clear Scotch tape on the side of the saddle that did not have a shim, and then got both of those wings perfectly aligned using the table level method. With the S670, it was so close to level that adding clear Scotch tape threw the alignment out the other way. Do not have any tape that is thinner.

The other thing is, the table alignment method, which uses the front wing tips and stab. bottom-side, does NOT give exactly the same result as the sighting method which uses the stab. tips and front wing top-side. So when I have the stab. and wing perfectly aligned using the table method, the sighting method shows one wing tip slightly lower. The table method uses the front wing tips which have a greater span so should be more sensitive than the sighting method which uses the narrower stab. tips. The sighting method is also influenced by my eyes, and they are not accurate, because when I used a tripod mounted camera in the padt I got a different result than what my eyes told me.

Shimming the wings is a little tricky, so here are some notes for using the table alignment method.

1) when foil is on the table and levels, if the Right side of the stab. is high as you lower the stab. end of the foil down to the level using the end of the fuselage, then the wing needs to be shimmed on the Left side. I will put a piece of blue painters tape on that side of the wing before remove foil from table, because you have to turn the foil upside down to remove the screws and that can confuse you as to which side of the wing needed shimming.

2) the closer to the centerline of the wing, the more effect a shim has (shim starts at centerline and goes all the way to far edge of saddle), so if you shimmed the Left-side of the wing to correct a stab. with a high Right-side, and the stab. then becomes high on the Left-side, you have three options, A) use a thinner shim on the Left-side of the wing, B) move the wing Left-side shim farther away from the centerline, C) add a very thin shim on the Right-side of the wing to try and split the difference (did that for F1080/F770 wings). I got lucky that I got the F1080 and F770 wings perfectly aligned with the stab., for S670 could not get it perfectly aligned, just very close and tried A,B, and C.

Turns out I was able to get the S670 wing perfectly aligned with the stab., initially I had 1 strip of clear Scotch tape far away from the wing centerline on the Left-side of the wing saddle, which left the stab. Right-side high, so tried putting the same tape on the Right-side of the wing, but that made stab. Left-side go high. So instead tried using a slightly thicker clear packing tape, the same way as above for the Scotch tape, and then the F670 wing was perfectly aligned with stab., i.e., both side of stab. touched the level at same time when lowering stab. end of foil to level using end of fuselage.

So it takes a selection of different thickness shims, but you can get the wings and stab. perfectly aligned. I used 2" wide stainless steel tape, 2" wide clear Gorilla tape, 2" wide packing tape, and 1/2" wide clear Scotch tape, with tapes listed in decreasing order of thickness. Just want to avoid using multiple layers of clear tape, since the glue will get squeezed out over time. So start with thick tape like SS tape first, if alignment is way off, and then fine tune with thinner clear tape.

Couple of notes:
1) if you have a side-shim taped on the stab. saddle and remove the stab and then reassemble, you need to re-check the alignment with the wings because it can change a little, guess it is due to the saddle on the fuselage being so narrow. Now I did make alignment marks on the stab. side-shim and fuselage saddle (light scratches) to make sure I got it back close.
2) I can get the stab. and wings aligned using the table level method so that as one side of the stab. just touches the level, while being lowered by the fuselage tail, the other side of the stab. is within the thickness of 1 piece of regular copier paper to the level. Think that is about as close as possible using side shims.
3) write down which side of stab. is high, and by how much, for each wing. So when you re-check at a later time you have a reference. If there are any major changes, check the stab. screw inserts to make sure they are not pulling out.

So the reason sighting down the fuselage to check the stab. and wing for level does not work is because I am so close when I do it that I have to use just my right eye, and then "if the stab. and wing are aligned using table level method" the right stab. tip is lower, if I use my left eye the stab. left tip is lower! So can use one eye, but need to use other one too, and if both stab. tips are lower by the same amount then stab. and wing are level. But the table level method does not have that issue, and is more sensitive and precise.

Got out today and used the AFS S670 cm2 wing with Aerotech Phantom 4.5 sail in conditions that I did not think I could get up in, but I did. And that was without a stab. front shim, so a properly aligned foil is more efficient, and that is obvious

So what I did not mention is on the last run of the session was ripping along and hit a manatee, stopped kit in its track and sent me flying. Wind was dropping and was worried about damage so slogged in to shore. Foil and board looked fine. But decided to check the wing and stab. for level at home, AND guess what? they were way out of alignment (see pic., Right side of stab. is raised above the RED level, Left-side of stab. is touching RED level). Checked first to see if it was due to wing or stab., used a drop level with foil on table and mast was straight so wing was good (see pic., drop level is triangular fishing lead weight hanging near top-side of fuselage) so somehow the stab. side-shim had increased the shimming effect, so trimmed side-shim away from centerline and got stab. back to level with wing.

What happened, I do not know, thought maybe a stab. screw insert came loose but both inserts were good. Maybe stab. side-shim shifted, does not take much to change the stab. level, but tried repositioning side-shim using alignment marks and it was still giving too much shim no matter how I placed it, so finally trimmed it back.

What was surprising to me is the wing was fine, and that is what should of hit the manatee first, but apparently the stab. hit it too.

Couple more notes: 1) when using tape to side shim the stab. some of the glue does squeeze out after a couple of assembly/disassembly cycles, and that will reduce the shimming. So I always go through 3-4 cycles before accepting the final result; 2) I always start with the tape going to the midline of the stab./wing, because if it is too much side shim (but close) I will then trim off 1/16-1/8 of the tape away from the midline to fine tune the shim, and of course you want to do that after 3-4 assembly/disassembly cycles. 3) the problem with using a plastic side shim for the stab., that is taped in place on the ends, is there is so little saddle to work with that small changes in the plastic side shim position can have significant effects on the stab. level. So I went back to using tape side shims on the stab.