Not sure what Axis is doing but F-one SK8, Cabrina, Omen and some others including me, we're loving the advantages of thinned tips and this general planform and front on profile with our own design variations. Curious as to how it feels though gybes because mine is like the SK8 reviews, silky smooth through chop, very noticeable and fast. But more flex, on mine at least.
This video is sooo helpful. I implemented this technique and especially focused on the hips stability. The results are amazing. I can say know that I really can switch my feet
Amazing, stoked to hear it wingfoilguy! Just like going up wind consistently I think being able to switch your feet confidently is such a great milestone to achieve in winging and really improves the overall experience. Hit me up to try an Operator foil if you'd like to experience a similar breakthrough in riding/turning :) greg@omenfoils.ocm
If at high speed foil (and board) are really pointing downwards it means fuselage isn't aligned with the flow. This increases both frontal area and drag coefficient of the fuse. Also then mast wouldn't be vertical like it is supposed to be for minimal drag but this is not that serious flaw than unaligned fuse. Correct method is to adjust foil for high speed so that fuse can ride level, because you want to ride at certain height and water surface is always level. Board don't have to be level and if it rides slightly nose up it helps against crashing when board hits water. If foil produces too much lift at high speed AoA of the front wing should be adjusted lower, not tilting the whole system under the board. Or having a foil which has less lift (smaller area, thin/less cambered airfoil). Of course shimming baseplate is simple but it less than ideal
Great points Bekanav, no doubt you are correct that operating past the designed efficiency range of your front wing also increases the drag due to the angle of the fuselage. So of course the best thing to do is to rig a smaller wing, however, this is not always an option, and some riders may need the larger wing to get on foil, so a baseplate shim is the best option in this case. On our Operator foils not only is the wing designed to have a broader efficiency range but also the fuselage is made smaller to reduce the drag when it is operating at lower or higher speeds than ideal. Together, this significantly increases the range of conditions that the foil can excel in.
@@omenfoils That makes sense. In some foils shimming front wing isn't even possible so then you have to try something else like shimming board/fuselage angle from the baseplate, if some changes are needed. I've always just thought foil should travel pretty much level when riding normal speed and it was a surprise to hear that some foils could have negative AoA at high speed. Of course amount of this can't be big, perhaps a degree or two and therefore can be tolerable even though it is a bit weird or less than ideal. I've made few complete foils and many wings during the years and then I had to think through the physics and variables. I have long history in kite design so things that fly were familiar to me, and foils just fly in water. Less than 10 years ago foils used to be much smaller but also much faster than now usual big foils. Winging wasn't around at all, it was all kite foiling. It was much harder to learn then because you needed more speed to get up and then crashes were harder. I remember how beat up I felt in first summer learning foiling😅 My latest project is monowing, just to see if it is usable or more fun. Auto stable airfoils are widely used in foil kites but there is of course many parameters to think and hopefully eyeball correctly enough. Nice shaping task anyway Last summer I tested a thick 1500cm2 foil and it was much too powerful for me, my speed was ridiculously slow and I had to keep my weight very much on front foot. I was kite foiling, for wing foiling it might have been a usable setup. What is best or most suitable for you is a personal matter and depends on your style of riding etc. Foiling is great sport but it also has that technical side in it. Some misunderstandings of foils, how they work and for tuning are quite usual. Good to see a channel like yours which clearly explains these things 👍
@@bekanav Thanks for the support and great engagement, you're absolutely correct the negative angle at high speed is generally very small, however it does cause a big drag penalty since the speed of the water is high over the wing and fuselage. Ultimately this non-linearly increasing drag is what places a practical speed limit for a foil at a specific rider weight. Similar principle applies to low speed which is why a larger foil will actaully be more efficient in small waves than a small foil since the angle of attack of a small foil operating just above it's stall speed is quite high it makes the whole system very inefficient.
many compliments for your detailed movie of the feet switch with unique tips that i have never heard before! i am on a DW board, so very long, as i understand, i don't have to lean my hips not forward but neither backyard can switch the feet even if my board is flat and not rising up the foil? the board must point downwind? can i ask you also some tips for riding toeside and Jibes? a big help when i try to jibe is to keep my weight forward, on my front feet... thanks for your lovely content, continue like this
Thanks Giovanni! The foot switch is the same on the DW board so no concern there, I actually think it's easier with longer boards as there is more momentum to a longer boards so it doesn't react as quickly to a small mistake in shifting your weight too far back or forward. Take another look at the video regarding the downwind comment, I ride a bit upwind while I am preparing for the switch to give myself more power in the wing to hold onto and become weightless, then once I switch I immediately point a bit more downwind to gain speed. This bit is fairly subtle here though, we're talking ~ 10 degrees or so each way. Do you have a specific issue with your toeside jibes? Maybe I need to do a specific video on them?
I weigh 70kg and I'm looking to change from the 89L board I'm currently riding to 67L. Thank you for the great video and it helped me a lot. Subscribe to the channel.
Thanks! I think you'll have a lot of fun with the smaller size! If you'd like to go even smaller and higher performance the 60L Flux would be a great fit, shoot me an email if you'd like to chat about it - greg@omenfoils.com
Great question Bewi! not in my opinion - I think the same attributes that make a great ocean board make a great lake board. I think about selecting the size of my board for the wind and sizing my foil for the waves. So if the wind strength is the same I'd ride the same board in the lake, however I'd size up my foil to deal with the slower waves. Alternatively, if there are no waves I might choose my smaller foil to practice high speed tacks and jibes. Hope this helps, happy to get more into the weeds on boards! Greg
Great videos on this subject Greg! Got a question for you: When winging in a straight line standing centred on top of the board and performing no other special action(s) I constantly have the feeling the board wants to "dive" (go down with the nose). I have tried to move the mast further forward, but that didn't change this feeling, I just had to stand a bit forward to compensate for that. I also tried to achieve the same by changing the angle of the stabiliser (I had it in neutral (not shimmed) initially), but it also didn't change anything on that "dive" feeling. And in the end I liked it most in the neutral position anyway. The strange thing is, that when I ride down a wave and hold the wing by the handle, the whole combination really performs well and the diving feeling totally disappears...??? Any ideas what's happening here? Any recommendations?
Thanks Ron! To answer your question it would be really helpful if you could try this during your next session and report back: Stand and ride around on your board as normal and ride around to confirm you're comfortable. Ride at a medium/slow pace and note where if the board has this tendency, increase your speed to medium fast and pay attention to the same, finally go as fast as you can and see how the feeling is changed. Don't move your feet at all through this process, once we know how the foot pressure/nose down dive feeling is changing relative to speed we can diagnose what is wrong with your tuning. Looking forward to hearing back! Greg
Dear Greg @omenfoils I just tried out your suggestion: When going slow, there's a slight raising tendency (nose up feeling) that I need to compensate by giving more front foot pressure. So I'm gliding above the water but don't have the board level with the water surface (nose up a bit). After a while, I manage to level out the board after which the board accelerates and reaches a medium speed. I now stand balanced over 2 feet, but I feel the constant diving tendency (nose down). Additionally I can say that this is the position and speed I'm in like 90% of the time. When I push to go to higher speeds, I can keep the board level with the water surface standing balanced over my 2 feet. However it feels like I'm on a bumpy road (in the up and down sense). Not stable at all and I have to correct constantly. By the way: All the above with my feet in the same stance/position. Does that make sense?
@@RonKolijn Totally makes sense Ron. Track position won't help this unfortunately. You either need a larger stabilizer, more angle of attack on your current stab, or a longer fuselage if you have one. I'd try shimming the stab first, make sure you are shimming the leading edge "downwards" relative to the direction of flight (ie. not down when your foil is flipped over and you are working on it). Start by adding 2.0 degrees, then try 1.5, 1.0, and 0.5. Choose the shim that provides most even foot pressure at high speed. Riding will feel more secure if you err on the side of a bit extra front foot pressure (more shim) but you'll get a touch more glide and low end by going the other way. Most folks are better off with a bit extra front foot pressure. Please let me know how it goes! Greg
@@omenfoils Dear Greg, I had an 'early-bird' session here in Holland this morning, as I was eager to try your suggestion(s) This morning I have put my stabiliser to the maximum angle (I own an AK Foil, that works slightly different, but the effect is the same as shimming) And guess what; the 'nosedive-feeling' totally disappeared! On max-speed in a straight line, it's still a bit bumpy, but far less than before, very well manageable. I really didn't expect this, as I thought it would slow down my foil and give me too much front-foot pressure, but no, all fine! This video and the one on tail wing shimming have made a lot of things more clear to me and certainly have helped me. And to top it off, your personal recommendation was the cherry on the pie. Big thanks to you Greg!!!
@@RonKolijn Right on Ron, very happy to hear it! Thanks for popping back in to share. This early in the sport there is still lots of misinformation and equipment available that does not work well out of the box - certainly serves to make things more interesting though! Try reducing the angle of the shim bit by bit to get a touch more performance, and let me know if you'd like to get your hands on some Omen gear :)
Greg, I'm 74 years old and probably too new to the sport to ask this question but... My long active life has given me some persistent right knee (back foot) pain after an hour of regular stance riding. I try to switch to goofy but on a good day the riding is %80-20. Would you suggest a track position that can lighten the back-foot loading? I read on forums of riders who never switch feet and this leaves me confused. Note: I still crash during foot-switching
Hey Kip, the easiest way to lighten the back foot loading is actaully just to stand further back on your board. If your foil is already in a balanced position you should keep it as is, but standing further back relative to the foil will put more pressure on your front leg. Have you checked out our most recent foot switch video? I definitely agree foot switching is incredibly important for keeping the body healthy if you're winging a lot!
Practice, practice, practice. Definitely completely agree with all these tips. I was inconsistent when I was just trying to quickly throw my feet to switch. All about raising up the nose just a touch when switching both directions and then just hammering in the reps until you don’t have to think about it. Such a critical skill to enjoy yourself out there, so much more efficient to go upwind when you’re heelside and not toeside. Side note, I have the Flux 60L and there is no doubt this board is more forgiving during touchdowns / mistakes. Makes a huge difference, love the board!
yeah, I think you could do pretty much the exact same technique except instead of just adjusting your feet berfor and after the switch you also pull them out and replace them into the straps.
I have done the hips advice and simply it works!!! The feet switch is softer and the back feet finds better the right place when it moves forward. My previous technique was based on pushing down the back foot but it generated more instability and it was worse specially in lighters winds. THANKS A LOT!😊
Help. Over 9 years of kite foiling I've become stuck in footswitching that isn't so good for winging. I've caught on to Winging pretty fast with only 8 sessions and now jibing regular stance non stop..... But.... My footswitching is a "shuffle" switch and makes for %90 failure crashes. I'm 74 years old and if I stay in regular stance for an hour of riding my back (right) knee develops 24 hours of old injury pain
Hi Kippy, have you tried the tips in the video for a couple sessions? If you describe when and how you are falling perhaps I can help. Or better yet, send me a short video clip: greg@omenfoils.com cheers!
I can switch from heel side to toe side every single time, but from from toe to heel, I am always falling. anyone facing this problem? any tips please ? next session I will try the hip tip.
Please try the hips trick and let us know how it goes! Can you describe how you are falling during the switch? If you have a video you're welcome to send it to me directly - greg@omenfoils.com cheers!
@omenfoils thanks. Ill try to take a vid next session, i remember just not having control over the foil. And foil coming out of the water and me falling backwards.
I have never tried to switch my feet on a normal prone surfboard but that would be pretty rad! This definitely works great on a kite surfboard though to prevent bogging down and keep speed.
@omenfoils, I can't thank you enough. You articulated exactly what was holding me back. I had been stuck for months, and today you unlocked it for me. Although I've only succeeded in about 30% so far, I now feel confident that with practice, I'll reach 100% soon. Thank you so much once again!
Great video. This is the first time I've heard someone mention the importance of the hips. I'm about 50% at this point and will definitely start focusing on the hips. For some reason I struggle to switch from heel side to toe side (as in can't). Keep the videos coming!
Thanks man, I would bet you'll get your success rate up to 90% within a few sessions - I think a lot of riders keep the hips back naturally without really realizing it, the foot switch is super hard without it! For the switch to toeside I'd recommend keeping your body very forward facing thoughout, or rather, don't try to step your "new" back foot too far back. I didn't mention in the video but also helps to push more up wind while you are travelling towards the apex and then switch to going more downwind right as you switch feet. This will help you get more lift from the wing and a less awkward stance when riding out toeside. Let me know how it goes!
@@omenfoils That’s what so many racers are doing, they footswap just before pulling into a heel side race gybe. The irregular twist in the body is quickly diverted into an initiated downwind direction. Ie race gybe.
Makes a big difference, doesn't it! Winging and kiting can be tough to practice on the water since there are multiple things that need to happen together to make a maneuver successful so the better we can isolate each step the easier it is to progress in my opinion. I'm also a big proponent of visualization to bring steps together between sessions.
👍🏼Great video / explanation. With a lighter Mast for my understanding you have to move the mast little back to compensate the stronger (same) lift force - correct
Thanks Mike! With a lighter mast you indeed want to move it back since the reduced weight at the back end would make the system front heavy so the mast is moved back to compensate :)
Hi, Do you ever ride on foot straps ? I only kite surfboards strapless, since 15 years ago, but it's hard for me to pump the wing board and to find the right spot for the front feet when strapless. Maybe this is a topic for a video
Great video! Weirdest combo I've ever used is a 1780 with a high aspect DW 157 tail. My question: On one of my foils when I put that specific DW 157 tail on (it's monoblock, no shimming allowed) the foil becomes incredibly difficult to get into the air. However, once in flight it is insanely fast and skatey which I like. I'm having a hard time understanding exactly why this makes it harder to take off, but so fun in the air. It doesn't have increased front foot pressure at speed, but it also doesn't have good takeoff, so I'm just a bit baffled as to if this tail is naturally sitting nose up? Down? Flat? Thanks!
Hey Bryan, that is a weird combo! I suspect the problem you are encountering is due to the tail being too small for the front wing as you can probably imagine. To explain what you are feeling thing about your take off with a larger tail. With the front wing at a high angle of attack you'll be getting positive lift from the tail which will decrease your stall speed. Also the larger tail (and also a more cambered planform) will produce significantly more downforce at low speed meaning it will be easy to balance. In your case your foil will be very hard to balance at slow speed but will get easier as you go faster and the high aspect tail starts to produce more and more downforce. Does this make sense? Ultimately it sounds like you know what you're doing, I would think a smaller foil with properly matched tail might actually be a better overall setup for you even in super light wind. Of course that is highly subjective though, curious to hear your weight and reasons for going to the 1780?
@@omenfoils well in the instance of the 1780 it was just for a test run to see if it would work, and it was fine! That was the first foil I ever paddled up. Never ride it anymore. For my recent issue it's actually on a 900 so I don't think the 157 DW tail is too small, but it seems like it has zero lift?
@@Bryan-Wouzel I get it now! I misunderstood and thought you were asking about the 1780. That is surprising the 157 doesn't create enough downforce for a 900. It would lead me to think it is very low camber section at a small angle of attack, however if that was the case it should provide good low end performance. Sorry Bryan, not sure I can help you on this one as I'm stumped as well!
73kg have a 34L 4'4 x17.5 strapped for windy conditions but for most conditions 4'8x20 50L. For light wind midlegnth 5'7x 17.5 75L with inserts this board works for everything but a bit large for jumping
Believe it or not, your lift force always equals the weight of the system when cruising. (Basic aero/hydro dynamic knowledge) Lift and weight are said to be balanced. When the lift gets bigger (than the weight) you start climbing (and opposite). Ideally you do not want your system to climb or drop as the speed (e.g. due to wind speed change) alters. Usually the gear starts to raise the nose as the speed increases which you compensate by moving your body mass slightly forward. If your original trim reacts as described so far you may shim your tail foil to give it less down angle. This reduces the overall nose up climbing which in turn must be compensated by either moving your body to the back (or the mast to the front) If this is trim procedure of reducing the down angle of the tail foil is overdone the gear will start dropping (instead of climbing) the nose as the speed increases. There exists a sweet spot for the tail foil angle where a change in speed wont let the nose either rise or drop such that no corrective relocation of the body mass is needed. It is not desirable to reduce the tail foil down angle so much that the nose drops with increasing speed, better to stay slightly away form this trim point. Better let the nose climb slightly (but not to much) with increasing speed. It should be noted that reducing the tail foil down angle comes together with a necessary relocation of the mass to the back (or mast to the front). As the center of gravity moves to the back the dynamic stability of the system is reduced. many tiny mass relocations correction are needed to compensate for this. If your trim has a rather large down angle the mass must relocate closer to the front this increases the dynamic stability but unfortunately gets you a nose climbing setup as the speed increases.
Hi There, did you watch the full video? I don't think I implied (and if I did, certainly didn't mean to) that the total lifting force increases or decreases with changing the tail shim. Only that (as you state above) that it will vary the rotational moment of the system which must be compensated for by the rider shifting weight as speed changes (or with a great tail design with the perfect shim is balanced through the full speed range).
Also, I would add that most stabilizers are not perfectly designed for the exact setup people are riding so getting them to balance at one speed does not necessarily mean that balance will be maintained through the speed range. This is one of the reasons we have a tail dedicated to each front wing and a shim recommendation for each mast length.
On your last point regarding relocation of mass that's what I was trying to demonstrate showing how my hips moved forward at high speed with "too much" tail shim and backwards with "too little". Maybe an animation would be more helpful to show these concepts. Sounds like you have a great understanding of flight dynamics, I didn't want to get into static and dynamic stability as the video was already a lot longer than I intended but it's a great point and one I hope to tackle in the future :)
Hi Very interesting topic. I’m struggling with my takeoff in surfoil and I’m planning to shim my mast. I use a gofoil foil with a north board. I feel like the front wing has to much incidence : - on small waves it is nearly impossible to gain speed (like if there was to much drag) - on more powerful waves I get ejected unless I put a lot of pressure on the front of the board (I tend to advance the COG very forward but if not enough speed the nose of the board plants in the water even with the mast at its most rear position). My idea is to shim the mast to decrease the angle of incidence of the front wing to help my takeoff and let me recenter the mast on the box. Do you have any comments on this strategy ? Will I have some difficulties with the stab ? You say that mast shim are more a board shim. It is true when flying because the pitch of the system is controlled by the foil. But when the board is on the water, the pitch of the system is controlled by the board lying on the water. Don’t you think that in this case it is more like a front wing incidence shim ? Last question : do you think that the source of power has an influence on the reasoning? When winging, the wing helps to unload the foil with its traction whereas on surf foil all the energy comes from the wave.
Hi Thomas, you are correct that the baseplate/board shim controls the angle of the board when the foil is flying but could be thought of as to control the angle of the foil when paddling the board on the surface. In your case it sounds like your foil has either too large of a tail wing or too much angle of attack (too much nose down angle) on the tail. This would make it feel draggier at low speed and have an overwhelming amount of front foot pressure at high speed. It could also lead to feeling like the foil is trying to rise too aggressively when catching a more powerful wave, however, I think this is more due to your foil being a bit too far foward in the tracks. Check out the video we made on tail tuning to get your tail dialed in. Similarly, watch our track position video and place your foil a bit further back than the balanced position to make it a bit easier on yourself when catching waves. The source of power matters, but in general wouldn't affect the way I tune since I'm optimizing for wave/bump riding either way.
Many thanks for your answer that add a lot to my comprehension … which stays quite low has this topic is very complicated ! About the position of the mast … it is already at its most back position. nothing to do here. I’ve watch carefully your video on the tail wing and will try to play this side … hopefully it will work ! Your videos are very nice and very well explained ! Very good job.
@@ThomasGic happy to help Thomas! Please let me know how it works, and if it's not possible to tune properly due to gear limitation get in touch with me for an upgrade :) greg@omenfoils.com
I designed up and 3D printed a shim to point my front wing down 2 degrees. I make all my own hydrofoils and just recently made my first carbon fibre mast. I put that 2 degree angle into my fuselage connection part of the bottom of the mast and ditched the shim. Either way, the result is more relaxed stance and not needing to partially fold my back leg.
Nice, that is one way to do pretty much the same thing! You'll likely want to re-shim your tail as well and now your mast and more importantly fuselage are flying at a slightly different angle. Depending on what speed your are trying to optimize for this could be a good or bad thing. Awesome that you are building your own gear man!
@@omenfoils Thanks, for me the biggest change for shimming (the mast) is not how it rides at all but my posture riding the foil. I still maintain my COG over the foil but the Axis gear uses a built in climb angle on the front wing which I don't agree with but I copied that angle for potential stabiliser compatibility part way along my own journey of wing design. To my mind, the wing already has an element of lift from foil top convex surface so if I want to climb MORE (Like starting or pumping or almost stalling) then I'll do it with angling the board with my feet. At cruising speed, I want the board flat, I want the front foil flat. At takeoff, I don't want the extra drag from mis-alignment of the board under surface and the foil angle. Of course Axis may have done it themselves in the beginning to compensate for boards with a lot of tail rocker, I'm sure they felt it was positive for them. I think they have reduced the climb angle on their newer foils since they started with it but it takes time, change the front foil angle and then you need to compensate with the rear stabiliser angle. Mast plate shims and doodad shim-angles leave that setting alone though, they just change the ride angle of the board. But you guys seem fairly tuned in, I forgot to mention on my first comment that the original shim was for the mast.
I was confused watching the video thinking that is opposite of what I feel with Armstrong. I guess with Armstrong you do the reverse? Start with no shim and then add shims until it feels balanced?
@@omenfoils you suggest that adding shims would make the nose of the stab point further down, but my shims are thicker towards the rear, so the nose of the stab points further up.
@@visskiss You have to think about it as changing the angle of attack of the tail wing. "Adding shims" is too general since the shim could increase or decrease the angle of attack.
@@Bravohi I believe Armstrong labels their shims the opposite of most brands and what I explain here. Start by shimming the front of the tail lower to get more downforce from the tail and then have the tail get "flatter" until you reach the sweet spot. Does that make sense?
great video, thanks. agreed on every thing you said and learned a few new ones, but there's something I didn't understand and would love a clarification about it. At minute 14 you start discussing what's wrong with too much angle of attack in the stab and you say "even though it might feel like more lift, it's only more front foot pressure, as there's actually less lift because the stab is creating more down force". I'm not sure what your definition of lift is, but if I "feel more lift" because of "more foot pressure", that's enough for me to call it... more lift! The stab is connected to the front foil via the fuse, so if the stab pushes down more, it makes the whole setup want to go up more and, again, that's what lift is in my world! And it's also compliant with one of my fundamental empirical observations I developed over years of experimenting: more lift always means more drag. So, why is it not more lift for you? Thanks!
great question gcgrammar, I didn't go into enough detail on this point as I was already aware the video was getting super long! The difference between "feeling" more lift as pressure on your front foot and more lift from the system is quite a big difference actually so important to understand. You are absolutely correct that generally more lift = more drag, however with the hydrofoil the front wing is lifting up (and creating drag) and the tail wing is "lifting" down (and creating drag). So this means if you add more "lift" to the tail by increasing it's angle of attack you get more drag, and also more front foot pressure since the tail is creating a rotational force which you need to counteract by shifting your weight forward. Nothing new there I'm sure but the next point is a key one! Every foil you have ever ridden is producing the same lift, if you think about it all it is lifting is itself, the board, and you - so whether it is a 2000cm front wing or 600cm front wing the "lift" is the same. The difference is what angle the foil is at to produce said lift through the speed range which corresponds to drag. So a large front wing will produce the same amount of lift as long as you can ride at the same speed, but the smaller wing will produce less drag (in general, as lots of other factors are at play). With this in mind, if you think about the tail producing more downforce, now the front wing has to produce more lift to counteract this downforce. This means the angle of attack of the front wing must increase slightly which also creates more drag. Does this make sense? Apologies for my complicated explanation, much easier to demonstrate with a white board or model!
@@omenfoils thanks a lot for putting that much effort in the explanation. I got your excellent point of any foil creating the same lift when it has to counteract the same weight (foil+board+rider), but with different drags depending on size and shape of the foil. That's why a 600 will always be faster than a 2000 if it's always me with my board riding it, I guess. But let's go back for a moment to the case you were presenting. If I increase the angle of attack of the stab and compare it to the same setup with less angle of attack, I now agree that at any same speed, the lift is the same. But doesn't adding more angle of attack to the tail also lowers the stall speed compared to less angle of attack? There'll be overall more drag, but if you have a steady pull from something (like a jet ski, for example), it should start flying a bit earlier than the same setup with less angle in the tail. That's my experience, at least, and that's why I call it (maybe technically incorrectly, I give you that) more lift. Thanks again!
@@gcammar happy to man, love chatting and thinking about this stuff. Often in explaining things it also sharpens my understanding or helps me to look at it from a new perspective. Most of what you are saying is 100% correct, with a jetski pulling you on a foil if you increase the angle of attack of the tail wing it will cause more drag and "feel" like more lift since you will get increasing front foot pressure as you speed up. The subtle thing you are missing though is when you take off the fuselage is not flying level, the whole foil is acting at a positive angle of attack. At this point the stabilizer actually provides additional lift since the angle of attack of the fuselage is so great. If you shim your tail for "more downforce" it actually reduces this angle and means you need more speed to take off. You will however get the feeling of stable flight starting at a slower speed, however as speed increases this will quickly go away and be replaced by too much front foot pressure.
@@omenfoils thank you, I love talking and understanding foils too. I understood the subtle thing you explained and yes, it opened up a new perspective for me. Here's the thing that makes me think it doesn't really apply to my case, though. I do four foiling disciplines (in order of preference): 1) Foil Drive (Plus, not gen2) assisted SUP foiling on waves, 2) Foil Drive assisted SUP foiling downwinders, 3) winging downwinders, 4) winging on waves. My Foil Drive board is 4.10x25x95L and my wing board is 5.0x26.5x90L, both custom and both with a perfectly straight rocker in the back half (if you really care, you can see them in this video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-pWp92_7AHPU.html) and that means that in all disciplines, I always take off by having the board plane first and then letting the foil come up out of mostly speed. In other words, I never really pump the board too hard when I take off and I keep the angle of attack of the board compared to the water surface always pretty small, no matter what foil I ride. So, in my particular case, it seems to me that in the pre-takeoff planing phase the fuse is always parallel to the water surface (because the board is still touching the water) and maybe that's why I experience the fact that a higher angle of attack of the stab makes the take off happen at a earlier moment/slower speed than with less angle of attack. Any thoughts now that I gave you more info? Thank you.
@@gcammar The board would still be at a positive angle of attack in order to plane but I do get your point that it is much less than stall so agree my point about getting positive lift from the shim is not relevant in your case. Perhaps you are shimming your tail to the same angle of attack as the board makes when planning which means the tail is at zero relative to your speed and giving the lowest possible drag meaning more energy can go into accelerating the front wing?
I recently joined the church of negative shimming last winter. Reducing the angle of incidence for the stabilizer has really helped with weight distribution and reduced drag. It also makes the foil less pitch sensitive.
Hey Tai, stoked you're getting great results with your gear, messing around with tuning is the best way to learn more about your gear. Negative shimming relative to what though is the question. Every brand has a different angle built into their tails so a "negative shim" on one brand might bring your foil into perfect tune while the same with another brand could be going too far and make it super unstable.
@@omenfoils I wish more brands listed their built in angles. The current Kraken fuselages from SABFoil have 2.3 degrees baked in, which is increased from their older fuselages.
@@taiguy yeah, lots of angles at play so it get's complicated fast. They probably don't want to overwhelm beginners with too much info. Ultimately though, the actual angle doesn't matter if you do this procedure to dial in the amount of shim.
Great job, Greg! Super clear information. I love that even though I'm a pretty tall rider, the Omen 850 Operator/87 Stiffy/Ahi small without any shim feels pretty great out of the box. It's one of the few rigs that I'm not feeling the need for a lot of faffing, even though it's something I kind of enjoy. You can just hop on and know it's sorted from the first ride and rip!🤙
It does come at a cost though! You'll notice your foil is harder to pump/generate speed going slow due to the lack of stability and also have to fight the tendency to nosedive at high speed. Have fun playing with it!
@@omenfoils Understood. I'm thinking for low energy downwinding where you might want a bit of help to get up, are often flirting with the low end of the foil, and have a paddle to assist in generating forward speed a negative shim might be a net benefit. Will see!
@@solentfoiler5969 yeah, you are definitely correct - how far you can push it without losing stability is the real question :) Looking forward to hearing how your experiments go!
