The question “Do bigger stabs provide more lift?” is ambiguous enough. I would ask the following question instead:
Could a different tail (e.g.: different area, type, differently shimmed, etc.) cause a change in front wing’s angle of attack? Given that you leave everything else unchanged. I’d say yes, of course it can.
And since the lift of the entire foil partly depends on the angle of attack of the front wing, it could well be that by changing to a different tail (and/or by shimming the tail differently) you change the amount of lift the foil produces.
I will say that I have been surfing the same spot, with the same gear, every two or three days for the last three weeks. Due to this thread, I put on the same version but larger tail on Sunday.
It felt like I had increased low end glide and pumping ability with a definitely lower stall speed. This change was what I was looking for, and I am thankful for this discussion.
I am an engineer, and I understand the force vector diagrams. I will say it does feel like increased lift. Although, I would better characterize this feeling as increased useablilty at the lower speeds I am operating at. Note, I am still in the beginner phases of prone foiling and although I have the foiling on a wave generally dialed, the catching waves and pumping around is challenging.
I have been winging waves for years and my strategy there is always a smaller rear foil to reduce drag and increase maneuverability. I have had smaller rear foils bring front foils to life.
I always shim my rear foils close to flat for reduced drag.
Your front foil obviously provides upwards lift. The tail is exactly what the name says. A stabilizer. It helps with pitch, yaw, and speed/glide.
Assuming your front wing remains the same, you can have thinner faster foils. You can have thicker slower tails. You can have higher aspect very wide tails that glide well. Your tail is technically pushing the fuselage down, which pushes the nose up. It provides resistance to pitch adjustments. Generally, the bigger the tail, the more resistance you have. It will be very stabile and in turn be difficult to turn.
This is where opinion comes in. Some riders like a larger front foil and a smaller tail. Some like a larger front foil and a larger tail. Some riders like small front foil, larger tail or smaller front foil and smaller tail. It’s all preference. What you want to do is match a front foil and tail with foil characteristics like speed.
For example, if you have a very low aspect, thick, slow front foil paired with a very thin, high aspect tail, it’s like your tail doesn’t achieve the speeds needed to work well because your front foil is too slow. Alternatively, if you have a super fast high aspect or mid aspect front foil and a big slow low aspect, tail, your front wing is begging to be unleashed and go faster and let loose.
So generally, high aspect foils like higher aspect tails, but it isn’t mandatory. And shimming. Depending on the brand, you can change the tail angle. This is what makes Armstrong so unique in my opinion as you can adjust nearly every aspect of your ride. The front foil and tail will have some sort of offset in angle of attack. Basically, your front foil pushes up, your tail pushes down. If the angle of attack has no offset, it’s the fastest setup you can have. If your offset in angle of attack is larger, you have more “lift” or nose-up tendency along with slower and more stable speeds. Think of a low offset as a tail that’s parallel with the surface with little to no drag. Now change that angle and you create more drag and lift. There is however a certain of angle attack you can shim your tail where your tail now pushes up the same as your front foil. I haven’t tried it but I am going to do it just as a proof of concept.
That was an amazing breakdown. I am still in the less is more stab camp but might start pulling out some bigger ones to make sure. One thing I do like about the larger stabs is the improvement on stall speed. Some of my best turns have happened at low speeds. thanks!
Literally JUST yesterday I tried my new Armstrong Speed 180 tail. Much faster and loose than my Surf 205. I nearly stalled a few times because I was used to the bigger tail. But the trade-off is I could actually flag out my wing and downwind. Before, I kinda struggled because my tail was too slow. I thought I just sucked at downwinding.
In regards to the dock starting video, the dude was able to apply more FRONT foot pressure with the bigger stabilizer without nose diving into the water with the bigger stabilizer.
When doing dock starts, I found it’s easier to get started with the bigger stabilizer because it’s forcing the nose up more, allowing more room for error. But once I’m actually pumping away from the dock, a smaller stabilizer is is easier to pump around due to reduced drag.