I understand there is more lift when mast is forward. But how does this translate to pumping efficiency? Is a more forward mast mean easier to pump?
Moving the foil forward doesn’t make it more efficient but tuning your tail for less lift (which then requires you move the mast forward to get the lift back) does make it more efficient.
When you tune the setup for less lift(smaller stab, less downward angle on stab) there is less interference between the front wing and back making the foil more efficient.
More downforce on the stab means the stab is pointing in a different direction than the front wing. If the wings point in the same direction it will be more efficient.
The more forward position makes the foil more responsive and harder to control “twitchy”. Your level of control is the limit of the efficicy you can gain from this.
This type of tune mostly benefits heavier riders. For a given wing a heavier rider needs to be going faster to stay above stall speed. The increased efficiency helps stay above that speed.
2 Likes
So the ultimate goal (if possible and within ability to control) is to have the mast in the most forward position with the smallest possible tail?
I’m on axis and have all the progressive tails from 300-400. I have found the 400 has a better pump but the 300 makes everything faster and looser with less pump.
You’re saying to go with the 300 (or smaller) and move the mast all the way forward? What if I moved my mast all the way forward and had the 400? Wouldn’t the 400 pump better?
Moving the mast forward isn’t your end goal.
Why Does CG Location Affect Your Airplane's Performance? | Boldmethod).
2 Likes
I was thinking about CG and the “balance test”
I thought that perhaps a better balance test would be setting your foil up so if you were walking along with the board in the water say to dockstart, and if you were to push the board, the optimal position would be that it glides as far as possible. If you had the foil too far back, it would sink to quickly, if the foil was too far forward, it would stall due to too much angle. I think this is a roundabout way of achieving the same thing as the balance test that James is talking about. My understanding is that you want the foil+board to contribute as neutrally as possible to the overall balance, and the overall balance is where you get the longest no-pump glide
2 Likes
Not necessarily. Efficiency isn’t everything. For a smaller rider you might find the foil becomes too slippery and your overfoiling sit out running the wave with that extra speed. Also there are limits to the effectiveness of that method I’m sure
I have the same question as Meow, but maybe a little different. Let me try to explain. Let’s assume the mast does not move in relation to the board but you stand further back. No changes to tail or tail angle or any other tuning changes.
Ignoring the increased effective weight of the nose, does the need to ride with more front foot pressure make it easier to pump? This is almost the same question as Meow’s, except for the increased swing weight of the nose of the board. But, my question relates more to making the technique easier rather than tuning for best efficiency.
The reason for my question is that I struggle to pump and tend to like to ride with my foot just in front of the mast and somewhat balanced front/rear foot pressure. Most people I see who pump well have their foot on or slightly behind the mast. It would seem to me that riding with a lot of front foot pressure would make pumping easier. I have been trying to relearn to foil like this and have had some minimal/inconsistent improvements when pumping.
The slower I’m moving, the more I find I need to have my back foot further ahead of the mast otherwise I’m more likely to stall the foil. If I’m moving fast, then I can pump with my back feet behind the mast.
here is a clip, right before the link turn, I move my back foot further back to be able to push more into the turn. I felt that coming out of the turn I was too slow and so I moved my back foot forward to avoid stalling the foil and to give a chance to pump away.
How this relates to your question - the position of the mast in your board doesn’t matter, as you’ll move your feet around (you should move your feet around) in a way that gives you the correct feeling for that context. Swing weight is incidental really for small prone boards.
The only thing that mast position does make a difference is takeoff, if the waves are powerful you can have the mast too far forward, and if the waves are weak you can have the mast too far back, but this can be overcome with a bit of adjusting the takeoff, and will have little to no impact once you are up and riding.
What does make a difference in making pumping easier is a baseplate shim, thick end at the back, which changes the angle of the board relative to your foil and can make a big difference
1 Like
initially it will make it easier to pump (not more efficient). all these questions are hard to answer because it depends on skill level and style. a really good foiler with wide stance will pump alot differently to someone with a narrow stance etc. but following the main principles outlined in teh thread definitely will get you on the road to the end goal. learning to pump efficiently takes years unfortunately.