How to setup the Liquid Force Medium Aspect Foil?

allenlight · Since 19 Jul 2008 44 Posts

So I've been foiling for a while now and have never been able to get a decent session on this foil. Not sure how to describe it, but it seems to take a lot of power to get any lift at all, and when it does go up it's really unstable. Oscillating up and down with the slightest amount of weight shift.

Ideally, I'd like it generate more lift earlier on and more gradually. I'm hoping this is just a matter of installing the appropriate shims and maybe locating the wings in the right positions on the fuselage. The wings came with a set of shims. One for the front and three different shims for the rear stabilizer. The rear shims are labeled 1.5 degree, 2.0 degree and 2.5 degree.

I've been running the wings with no shims at all and on the furthest ends of the fuselage so far. Any advice on which shims to use and where to place to the wings on the fuse to make this a more user friendly setup would be greatly appreciated.

For reference on my normal foiling setup; I'm very comfortable running this same mast and fuse with the LF Impulse 110 wing set (no shims) and I also have the Slingshot GW 633 setup which works great.

macgruber · Since 06 Dec 2011 490 Posts SE PDX volcano Obsessed

Had it and I think I used the highest degree but Pepi at Pure Stoke would know for sure. I never really liked it though. Thruster and Impulse were a lot better. I wish the Thruster could have worked on the carbon fuselage. Liking the Phantasm 657 now

Singlemalt · Since 21 Jun 2015 475 Posts White Salmon Obsessed

I’d love to hear about it, if you get it figured out. I haven’t.

It’s a pretty small wing. About 550 square cm, if I recall correctly. And it came out a while back. All the video I’ve seen had fairly light weight guys, who were already skilled foilers, making it work.

At 200 lb, wings in the 900 sq/cm range seem to be my sweet spot. Maybe one day I’ll figure the happy foil out. Or it’ll collect dust until the next swap meet.

I think there was a lot of spaghetti thrown at the walls in the rush to grab a chunk of the foil market.

Pepi · Fri Dec 09, 22 2:59 pm

sfbomber · Since 27 Jun 2012 114 Posts Stoked

I'd go one extreme to the other (no shim to biggest shim).
No experience on this fuselage, but a well designed fuselage with no shim will have 0 angle on the stabilizer for optimal minimal drag. Once you start introducing angle on the stabilizer, the drag goes up. But you will also find that your lift goes up with more shim. If 2.5 is not enough, maybe try stacking shims, i.e 1.5+ 2.0 (with longer bolts if necessary).
https://www.youtube.com/watch?v=kaj4JqE2n5Y
I'd keep the spacing between the front of the front wing and the front of the rear wing to the maximum spacing if your are looking for stability.
Does this mount with a tuttle box or plate mount. If plate mount, you could try 1/4" movements in the plate.

sfbomber · Since 27 Jun 2012 114 Posts Stoked

I came across a setup video for this foil:
https://www.youtube.com/watch?v=kHZ0eHBHU8w
In it he uses the most rear bolt settings for the rear foil and the most forward bolt settings for the front foil. He used shims for both the front and rear foil, which appears the same as allenlight set up his above (except no shims).
There are some pictures of the foil setup on this web page too, which look like it was setup similarly.
https://www.iksurfmag.com/reviews/boards/hydrofoil-boards/liquid-force-kites-happy-foil-and-happy-foil-board-4-10-2017/
I had my first go on this foil recently. I setup the foil differently. I used the front foil bolts that are closer to the mast. The idea was to get the center of lift closer to the mast. I used the rear foil bolts that are closer to the mast (on accident), I meant to use the bolt pattern with the rear wing farthest from the mast for more stability.
I had recently used the rear happy wing with the most rear bolt spacing farthest from the mast, and the 1.5 rear shim using the black rocket foil as the front wing. I have a strong dislike for the rocket rear wing as it feels super slow (which is ok for absolute beginners). I prefer the thruster rear wing with the black rocket front wing (also works with the impulse front wing). With the black rocket front wing and rear happy foil wing combo, it worked with the 1.5 shim. I believe this is the fastest shim for the rear happy foil wing with the least amount of front foot pressure. It made me feel like trying the 2.0 shim next. It did feel like you lose some low end with rear happy foil with this setup (similar lift to thruster foil set combo, which is a better setup)
Back to the happy front and rear foil combo, I was able to get up on foil. I wish I would have used the most rear bolt spacing for the rear wing. But using the front bolt closer to the mast seemed to still work. It would be interesting to compare front wing back/rear wing back and front wing forward/rear wing forward relative to the mast, and seeing which system is more stable but still turns well. It also made me want to try a taller rear shim. The impression I got was this foil is meant to be ridden powered where I would be on the same size kite as I would be on my surfboard or skimboard. Any time I would lose kite power, I would lose speed and lose lift.
Coming from an impulse the takeoff speed is completely different. The impulse (1126 cm2) you can take off in 1st gear. With the black rocket (860 cm2) you can take off in 2nd gear. With the thruster (774 cm2) you can take off in 3rd gear. With the happy (564 cm2) you can take off in 4th gear. That is coming from a 200# rider on a 4'2" liquid force galaxy board with the mast plate at the back of the box. With these 4 wings, I could have only 1 kite and pick a wing to match the conditions. Or if I only had one foil and many kites, in the same conditions, I could use a impulse with a 7M kite, the black rocket with e 9M kite, the thruster with a 11M kite, and the happy with a 13M kite.
My favorite for light winds is the Cloud IX designed impulse and I like the Matt Wheeler designed Thruster for when there is more energy in the water. The thruster has a decent low end for its size, you just have to keep your speed up. I willI continue to experiment with the rear happy wing with different front wings. But the Thruster covers my needs for a front wing over the happy.

For an initial happy setup, the 2.5 rear shim could provide the most lift and most front foot pressure. I would use the more rear bolt spacing away from the mast for the rear foil for the most pitch and yaw stability. Front wing on the bolts farthest from the mast should offer the most pitch and yaw stability. . Be sure to use the shim for the front wing. Pay attention to the arrows of the shims so that they are pointed towards the front of the system.

The happy is a much smaller setup to what you have been riding. The 633 is 1214 cm2 with an aspect ratio of 3.3. The impulse is 1126 cm2 with a similar aspect ratio of 3.3. Whereas the happy is 564 cm2 with an aspect ratio of 6.5, more similar to Moses 550 (572 cm2, AR 6.3). And for reference the thruster has an aspect ratio of 4.2 and the rocket has an aspect ratio of 3.5. The Phantasm 657 is 743 cm2 with an apsect ratio of 5.8. In terms of grouping the GW 633, Impulse, and rocket are freeride foils. the thruster is a powered freeride foil, and the happy is a powered speed foil.

This video describes what shimming does for the rear wing:
https://youtu.be/sX2gz0pFv1g?si=gCq5E9G5zdk0GKBS

This video describes the effect of mast position on the board:
https://youtu.be/wMTM-CioJ0o?si=OjiTy-EEXrducHS1
I believe Kane De Wild states the center of lift is approximately on the first 1/3 chord of the front wing, not the center of the chord as mentioned in the video.