Neil Pryde F4 Carbon Foils with slalom board...

just wondering if anyone has used these foils with thier slalom gear with any success?

i tried a set of these in my JP 85 wide slalom board and struggled to get them to fly the board like I can with the RS Flight AL foils. I kept moving my mast track back til the foot was almost out of the track but the board still kept wanting to touch the water constantly. I had the rear stabiliser in the highest lift position as well. Any thoughts?

Cheers. :)

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CJW said..
Something sounds wrong because the f4 carbon foil is a way more powerful foil than the AL flight. Big front wing? Are you sure you had the rear stab trimmed correctly? Same board you used both foils on yeah?

Yeah I couldn't work out what was going on either CJW. I had the big wing on and the rear stabiliser was as far in the lift position as I could get. It was 18mm from straight but I was struggling to keep it flying. It's the same board I used for my AL foils which give me heaps of lift.

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CJW said..
Yep that's pretty weird because every experience I have had between the two is the opposite. That said I did extend my F4 fuselage 300mm but that's more to do with racing, big sails and upwind performance. With the stock config, rear stab maxed (I got mine to about 19mm) I found it had way more lift than an AL:Flight (JP 135).

Yeah that is interesting. I'm using my full slalom racing sails as well but the AL foils seem to give me much more lift.

Thanks for your input Paducah. Yes I measured my rear stabiliser angle with Sean who is a very experienced foiler in WA that also uses the NP F4 foils, and it was reading 18mm, and yes the rear stabiliser was pointing down at the front.

Im going to try and get out tonight again and measure the angle of the foil parallel to the bottom of the board to see if that may be the issue. If it's not then I don't know what else it could be.

All good mate. I appreciate the input from people who have had more experience with these foils and foiling in general as I've only started foiling in the last few months. It may just be that I need proper foiling boards to get it to work at its best as I find the wider wings on the F4 are harder to control without the extra width of full foil boards. I'll give it a few more goes and if it's no better I'll stick with the Ali foil. Cheers. :)

Still has me a bit confused
Foil appeared to be setup fine, did measure stabilizer but nothing else
Yes definitely straps were not ideal for a F4 being a little inboard and a little bit too forward but this doesn't explain matt feeling like the ali had more lift
Pretty sure the symptoms point towards the front wing being at a unusual angle either due to its mounting or the entire foils fit in the box, still sounds strange to me
Will have to have a better look

Same size sails, same wind strengths? Just trying to reduce all possible variables but honestly I don't think I can help

I will say though that in standard form the F4 is a twitchy foil, very sensitive to rig and foot pressure changes, more so than the AL; I found anyway. However, I find it very quite neutral in terms of lift changes with speed till you get right up to the top end (i'm talking 26-27kts) when in the config I usually sail it, it becomes hard to keep it in the water.

When you get it flying does it seem like the board is flying bow down? I don't think I've ever measured it (I can check tomorrow) but I don't think I run the fuselage parallel to the board, I think if anything the fuselage is closer at the back of the board (so if fuse is parallel to the water the board is flying slightly bow up). If your board is flying bow down the wind over the deck could be pushing the nose down to the water, particularly up/cross wind and in windier conditions. As Sean said, weird front wind setup or something like that is the only thing I can think of

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CJW said..
Same size sails, same wind strengths? Just trying to reduce all possible variables but honestly I don't think I can help

I will say though that in standard form the F4 is a twitchy foil, very sensitive to rig and foot pressure changes, more so than the AL; I found anyway. However, I find it very quite neutral in terms of lift changes with speed till you get right up to the top end (i'm talking 26-27kts) when in the config I usually sail it, it becomes hard to keep it in the water.

When you get it flying does it seem like the board is flying bow down? I don't think I've ever measured it (I can check tomorrow) but I don't think I run the fuselage parallel to the board, I think if anything the fuselage is closer at the back of the board (so if fuse is parallel to the water the board is flying slightly bow up). If your board is flying bow down the wind over the deck could be pushing the nose down to the water, particularly up/cross wind and in windier conditions. As Sean said, weird front wind setup or something like that is the only thing I can think of

All the same gear as last time CJW. The board doesn't fly bow down, it just wants to keep touching down on the water as if the rear stabiliser was in neutral. I was under the impression that the carbon foils from Neil pryde were not as twitchy as the aluminium foil's because they have more lift, but I can fly the AL foils with no problems.

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Maddlad said..

Paducah said..

Maddlad said..

scarrgo said..
Still has me a bit confused
Foil appeared to be setup fine, did measure stabilizer but nothing else
Yes definitely straps were not ideal for a F4 being a little inboard and a little bit too forward but this doesn't explain matt feeling like the ali had more lift
Pretty sure the symptoms point towards the front wing being at a unusual angle either due to its mounting or the entire foils fit in the box, still sounds strange to me
Will have to have a better look

Today I measured the angle of the fuselage to try and make sure it was parallel to the bottom of the board as I thought that might be the issue, but everything was pretty much level. I moved all my straps to the very back holes and had the stabiliser at max lift, and yet I still had problems flying.
The way it is at the moment, I have to put so much pressure on my back foot just to keep it flying, and then when I get hit by a gust it just wants to fly up too quickly. With my AL foils I can set it up so I have a neutral stance on my deck which makes it easier to account for lulls or gusts and keep it flying. With the F4 foils I'm having to have my mast track so far back it's nearly coming out of my board and the board still keeps wanting to touch the water most of the time.
I think I'll just stick with the AL foils at this stage.

What is the relationship between the back strap and the front foil screw? ie how far forward or backward is the back strap screw from the front bolt?
What is the distance from the front foil screw to the center of the mast base?
Have you tried with no back straps to see where the board balances?

Let's assume the fuselage lines up with the front wing, the fuselage should be angled down about 3 degrees so that when the wing flies straight, the board nose is pitched up a bit. The Glissattitude article covers why but in a nut shell, takes offs and touch downs are both easier.

This is probably the most frustrating thing about foiling is how cms can make such a difference and why dedicated gear can help. You are trying to learn to fly at the same time as tuning your equipment for something you don't quite know how to do yet. On my first board, I'd literally have to yank the board out of the water to fly because I naively assumed that the "middle" settings that worked for regular windsurfing would be fine. They weren't

Here's the board and foil showing the distance between the strap and foil position. As I mentioned in my post above, I don't have any troubles flying the aluminium for oil, it's just this carbon one that doesn't seem to work with my board.

Sorry, hard to read the tape measure from here. (It really does get down to cm) But it does look like the back straps are somewhat beside the foil rather than in front of it and I'm going to guess you have the mast base not too far forward. Thanks for indulging me. I hope smarter minds than me can help you suss this out. Good luck!

btw, you have really nice kit.

Go borrow the second hand 135 foil board from WSP, you have obviously spent lots of $$$ there and obviously looking to spend many more. If the F4 works on that you have a board problem, if it doesn't, who knows. Reg will love the opportunity to sell you a new board as well as the foil.
Good luck. Leave your credit card at home till you know it works for you.

The F4 will be high on my shortlist of toys when i feel the need for more speed, but for now im just happy cruising around. Still got allot to learn.

I used the NP/F4 on my RRD slalom board (225 x 79 @ 122 liters before I got the JP 135) and it worked really well.

I had also learned to foil on the NP pinkie before switching to the F4 and found the F4 to be very sensitive if you do not get enough
board speed first. It will climb out, but suddenly come back down if your not going quick enough. You cannot foil the F4 like the Aluminum, you have to be much more aggressive.

On the RRD I had all foot straps forward with mast base slightly forward of middle of the track.

On the JP 135 its the complete opposite, all the straps are back with mast base slightly back from middle.

Which sail size are you using in which wind speeds? (I am 90kg and can foil in 10/11 knots puff and foil through sub 8 knots with a 7.8)

Take a pic of the board deck and measure center of your deck plate to the first bolt hole, and I will measure the RRD to see where you are at?

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Maddlad said..



Here's the board and foil showing the distance between the strap and foil position. As I mentioned in my post above, I don't have any troubles flying the aluminium for oil, it's just this carbon one that doesn't seem to work with my board.

I have recently started foiling and I have had similar problem.
My first question is why are you asking this forum and not asking your foil manufacturer? Indeed: Thank you for asking us and we will help as much as our knowledge extends. But I have gotten my foil tuned correctly on my first session by texting with my foil manufacturer.

Now what I think about your setup:
These integrated mast + fuselage foils have short fuselage. The main reason for the short fuselage is to fit into a shipping box in order to keep total price down. Longer fuselage would already fly with even not perfect angles. Starboard Race is an example. On the short fuselage you have very little margin for errors on angles setup.
From your description and the picture I think your center of gravity is too much forward in relation to the main wing. Your stabilizer is not generating enough force down to counter balance your weight. Larger stabilizer would probably be an improvement, but it will be more drag. Your stabilizer has probably also small leading edge radius for more speed, but it results in reduction of maximum angle of attack.
I assume you cannot move your wing forward. It means you need to move yourself back. The easiest way to move yourself back is to put more pressure on your back foot. If this works it means that your know what to do. You can move your foot straps back, move mast base back. If not enough check if the mast fits right in the finbox. See if it tilted back.
The next adjustment step is to reduce angle of attack on the main wing. Reduced angle of attack will force you to fly with your nose more up so you foil mast will lean back - it will shift your center of gravity back - this is what you need to unload the stab.
You may need to reduce the angle on the stab because it seems to be too much if the foil want to fly out of water. Ideally you want to have the stab at 0 angle, but it will be sell stable, and more fast.
Note, the stab angle is important in relation to the angle of the main wing for a stable flight. If you need a very large stab angle it means you need to move your center of gravity.
I use a foil that can be moved +/- 8 inch along the board so it is easy for me to adjust while keeping the optimal angle on the wing and the stab factory preset. This is what my foil manufacturer texted my when I was on the spot testing ti for the first time - move entire foil assembly forward. And it worked right away nice and easy to control while fast. But your foil connection to the board is fixed. You cannot move you foil without moving the finbox. It does not mean that the foil is bad, It just means that your foil is more sensitive so little adjustments so even hydrofoling experts like like above do not know what is going on.
If I watched you on water it would be more clear what to do. But I think you need to reduce the angle on your main wing (reduce lift), Or try a smaller wing with current angle?

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XYZ said..

Maddlad said..



Here's the board and foil showing the distance between the strap and foil position. As I mentioned in my post above, I don't have any troubles flying the aluminium for oil, it's just this carbon one that doesn't seem to work with my board.

I have recently started foiling and I have had similar problem.
My first question is why are you asking this forum and not asking your foil manufacturer? Indeed: Thank you for asking us and we will help as much as our knowledge extends. But I have gotten my foil tuned correctly on my first session by texting with my foil manufacturer.

Now what I think about your setup:
These integrated mast + fuselage foils have short fuselage. The main reason for the short fuselage is to fit into a shipping box in order to keep total price down. Longer fuselage would already fly with even not perfect angles. Starboard Race is an example. On the short fuselage you have very little margin for errors on angles setup.
From your description and the picture I think your center of gravity is too much forward in relation to the main wing. Your stabilizer is not generating enough force down to counter balance your weight. Larger stabilizer would probably be an improvement, but it will be more drag. Your stabilizer has probably also small leading edge radius for more speed, but it results in reduction of maximum angle of attack.
I assume you cannot move your wing forward. It means you need to move yourself back. The easiest way to move yourself back is to put more pressure on your back foot. If this works it means that your know what to do. You can move your foot straps back, move mast base back. If not enough check if the mast fits right in the finbox. See if it tilted back.
The next adjustment step is to reduce angle of attack on the main wing. Reduced angle of attack will force you to fly with your nose more up so you foil mast will lean back - it will shift your center of gravity back - this is what you need to unload the stab.
You may need to reduce the angle on the stab because it seems to be too much if the foil want to fly out of water. Ideally you want to have the stab at 0 angle, but it will be sell stable, and more fast.
Note, the stab angle is important in relation to the angle of the main wing for a stable flight. If you need a very large stab angle it means you need to move your center of gravity.
I use a foil that can be moved +/- 8 inch along the board so it is easy for me to adjust while keeping the optimal angle on the wing and the stab factory preset. This is what my foil manufacturer texted my when I was on the spot testing ti for the first time - move entire foil assembly forward. And it worked right away nice and easy to control while fast. But your foil connection to the board is fixed. You cannot move you foil without moving the finbox. It does not mean that the foil is bad, It just means that your foil is more sensitive so little adjustments so even hydrofoling experts like like above do not know what is going on.
If I watched you on water it would be more clear what to do. But I think you need to reduce the angle on your main wing (reduce lift), Or try a smaller wing with current angle?

Lot of advice there, for someone who "recently started foiling".

The dude is a mystery >_>

Anyway sounds like Maddlad is sticking with the AL, not a bad idea as those new wings look pretty nice and a lot cheaper than the F4.

Personally, and this is coming from someone who owns and races the F4....the best foil on the market in the high performance area is the Starboard team setup. It covers every base, short setup like the F4 but a long stable setup if you are serious about racing and other options in between. It's also modular, so easy to upgrade with new wings, different mast, fuselages etc as they release them. I sail regularly against the starboard race setup and while my F4 is competitive it's heavily modified. Top end wise I think the F4 is a faster but that isn't the only factor on a race course where VMG is king.

It appears that Hydrofoils sold as JP and NP are manufactured by the same factory that makes F4 foils. Do I see it correctly?
F4 did not work for you and the same manufacturer replaced it on a better foil but with a different label.
BTW, bringing the issue to the manufacturer, in my opinion, was the way to go as someone above suggested.