Frictional Resistance, Rf - the resistance created by the movement of the wetted surface through the water, chiefly the turbulence at the intreface between water clinging to the hull and that which is flowing past, proportional to the wetted surface and the only significant resistance at low and very high (planing) speeds. Hydrodynamic Side Force, Fs (the turn) - the element of the hydrodynamic force acting perpendicular to the course consequent to the lift created by the hull and its fins moving through the water at a speed, Vs, and a leeway angle, ^ make this work better, than flex means nothing
Man i’m tring to keep it simple… Then You go and post this??? Rf… can’t do much with this till someone comes up with a better Dolphin Skin?? Wet sanded finish is as close as we can get to controling Rf… Fs… we do our best to design boards that do it all. each board has it’s own needs as far as fin lay out goes. We change cant, toe how far we set the fins from the tail add canards to direct water around our lead fins. Then we find that by adding lift with concaves we can channel water thru all our fins and we start using words like Vortex and my god it goes on and on and on… I believe we have learn to get max Drive with the lease amount of leeway angle slide… All the fins, channels and concaves rail designs has let us move thru the water on smaller boards then we ever thought we could say 15 years ago. So i think we have reached our level of drive and control. All we been doing really is changing our design a little to fit the needs of the surfing styles of now… Boards that will launch and land better then the boards of 15 years ago. Everything else we have done for twenty years hasen’t made much of a difference. make this work better, than flex means nothing>>> >> It’s the next step and i think it mean everything for small wave surfing… We have little control in making water slide over its self. We have learn to control Fs it’s been a standard for 20 years now. We just haven’t put much time into controling “Flex” and the benifits of twist as in a spoon… increasing the force of spring in a surfboard as Flex in Snowboards and skis… Flex is the future. Ask why Rusty has put so much time into Flex design… Ask CJ if he thinks flex works… Hell ask anyone who has felt what flex can do to a surfcraft. So Chris do you really think that flex means nothing if we could control water flow over any given surface. Do we really need more drive with less slide… It’s a give and take thing you know. Now lets add a little more spring out of our board when we put them on rail. The thing is we have learn to improve Rf and Fs but we haven’t made any improvements with Flex. the third element…>>> Frictional Resistance, Rf>>> - the resistance created by the movement of the wetted surface through the > water, chiefly the turbulence at the intreface between water clinging to > the hull and that which is flowing past, proportional to the wetted > surface and the only significant resistance at low and very high (planing) > speeds.>>> Hydrodynamic Side Force, Fs (the turn)>>> - the element of the hydrodynamic force acting perpendicular to the course > consequent to the lift created by the hull and its fins moving through the > water at a speed, Vs, and a leeway angle, ^>>> make this work better, than flex means nothing http://surfnwsc.com
Man i’m tring to keep it simple… Then You go and post this???>>> Rf… can’t do much with this till someone comes up with a better Dolphin > Skin?? Wet sanded finish is as close as we can get to controling Rf…>>> Fs… we do our best to design boards that do it all. each board has it’s > own needs as far as fin lay out goes. We change cant, toe how far we set > the fins from the tail add canards to direct water around our lead fins. > Then we find that by adding lift with concaves we can channel water thru > all our fins and we start using words like Vortex and my god it goes on > and on and on… I believe we have learn to get max Drive with the lease > amount of leeway angle slide… All the fins, channels and concaves rail > designs has let us move thru the water on smaller boards then we ever > thought we could say 15 years ago. So i think we have reached our level of > drive and control. All we been doing really is changing our design a > little to fit the needs of the surfing styles of now… Boards that will > launch and land better then the boards of 15 years ago. Everything else we > have done for twenty years hasen’t made much of a difference.>>> make this work better, than flex means nothing>>>>>> Flex is the future. Ask why Rusty has put so much time into Flex design… > Ask CJ if he thinks flex works… Hell ask anyone who has felt what flex > can do to a surfcraft.>>> So Chris do you really think that flex means nothing if we could control > water flow over any given surface. Do we really need more drive with less > slide… It’s a give and take thing you know. Now lets add a little more > spring out of our board when we put them on rail.>>> The thing is we have learn to improve Rf and Fs but we haven’t made any > improvements with Flex. the third element… Rob, Flex in snowboards and downhill skis provide for a smoother transition from one edge to the other. This turning is only to provide more friction from the fall line of g=gm/r2 acceleration due to gravity. The maneuvering to stop acceleration is the fun part. Surfing deals with two variables gravity and wave energy. To utilze the full force of wave energy big or small would be to stand out of the way of flex. The laminar flow is greater on a flat surface that will not flex. “When you have two competing theories which make exactly the same predictions,the one that is simpler is the better.” or “Entities should not be multiplied unnecessarily.” - Accoms Razor surfsup
Rob,>>> Flex in snowboards and downhill skis provide for a smoother transition > from one edge to the other. This turning is only to provide more friction > from the fall line of g=gm/r2 acceleration due to gravity. The maneuvering > to stop acceleration is the fun part. Surfing deals with two variables > gravity and wave energy. To utilze the full force of wave energy big or > small would be to stand out of the way of flex. The laminar flow is > greater on a flat surface that will not flex. I’m reticent to enter this discussion, because you are either ignorant of the practical application of flex, or you are simple jerking your chain while waiting for the Raider game to start. Properly applied flex characterisitice in a surfcraft design is NOT a theory. It is something which has been successfully applied for OVER 35 YEARS. The only reason is is not the standard of conventional surfboards is because the materials do not exists, in affordable form, which allow for both controllable bending and bouyancy. You seem to presume that drag and speed are at odds in surfcraft design. They are not. Speed is the result is proper drag management. A dead straight outlined, flat rockered board with minimal induced drag would be limited in it’s speed potential in most wave conditions. The lack of drag would force the craft down to the base of the wave, where little usable power exists. When drag is introduced in the proper manner (I won’t go into the details of that here, not enough time) the track of the board becomes more parallel…utilizing the power of the wave more effeciently. Practical application has proven this time after time after time. A dramatic indication that drag can and does result in greater speed: look at thrusters surfing a wave like Kirra. They enter a long tubing section low, make seemingly unmakable section after section, and exit the tube at a higher wave altitude than they entered. All of this was the result of the drag induced by the outline, rocker and outer fin toe-in. The board is allowed to find the most effecient track along the upper portion of the face BECAUSE OF DRAG. A flatter, straighter board would wash out and run down the face and be passed by…regardless of who was riding it. The concept of flex does not presume to say that if we were to take that same thruster and introduce flex it would be faster or turn with more accelleration. What it does presume to say is that if we were to remove a degree of the induced drag (say, flatten the rocker line and outline curve) and re-introduce that drag with flex, then the drag would be variable…less when the rider is unweighted and trimming, more when the rail and tail are loaded up in a turn. Both situations would result in more effective use of drag. (A board with tail flex can turn with greater accelleration because more of the rail line can be loaded up in a turn without rider hesitiation. The “smoother transition” you speak of in snow boarding applies to surfing as well…and on the right board, can result in a dramatic increase in speed.) Another way to look at drag as a source of speed is to break down the misconception that “lift” is soley the result of planing effeciency. Lift, in surfcraft, is generated by two things: Planing over flat water (like a water ski), and wave face elevation. Drag is what allows a board to be “lifted” off the base of the wave and into the more powerful mid-section. A board with no induced drag would plane easily, but it could only run along the base of the wave. “Lift” generated by drag is needed to pull the craft away from the dead water along the base and into the power higher up the face. So, a combination of planing and drag-induced lift are needed to reach speed potential. Drag management…that’s what good design is. And, flex has a viable place in that combination. Again, I seem to speaking in theory. I am not. I have had access to and ridden, FOR DECADES, the entire evolution of George Greenough’s kneeboard collection. I’ve experienced first hand the transition between a solid balsa kneeboard and that same board (via molding) as a flexible,torsion stressed form. The difference in both trim speed, accelleration in turns and directional manueverabilty is astonishing.
Sorry, Rob, Paul, My microstate attempt at playing devils advocate for those out there who stoped thinking.
Frictional Resistance, Rf My brain hurts. Chris, you need to go out and surf.>>> - the resistance created by the movement of the wetted surface through the > water, chiefly the turbulence at the intreface between water clinging to > the hull and that which is flowing past, proportional to the wetted > surface and the only significant resistance at low and very high (planing) > speeds.>>> Hydrodynamic Side Force, Fs (the turn)>>> - the element of the hydrodynamic force acting perpendicular to the course > consequent to the lift created by the hull and its fins moving through the > water at a speed, Vs, and a leeway angle, ^>>> make this work better, than flex means nothing
I’m not thinking clearly after reading all this. I actually posted twice due to the scrambling of my brain cells. Chris, please go out now and catch some waves.
My microstate attempt at playing devils advocate for those out there who > stoped thinking. Man i could shoot you right now??? I would have to say you did what you attempted I was so stressed now i can go shape #1 it all stock ( no flex )and will be the model that all will follow… Paul you the man… I almost called you last night… Thanks Chris for making my day… Time to shape with all the Fs and Rf going thru my mind??? http://surfnwsc.com
well, flex has been toyed with for many years, unbeknowing to many… flyers, flutes,fin systems & placement, concaves and channels have all affected performance both thru drag and drive (generally percieved and accepted) but these additions also affected flex. im actually doing the opposite to rusty and cj with stopping the flex at the tail and increasing further forward! we have found flex in the tail for powerfull waves and solid surfers to be slow turning.flex tails seem to unload way to early in a solid turn creating unwanted drag 3/4 way thru the turn. having channels in a quite flexible glassing combo (stringerless) actually increases speed thru turns and makes for much better drive on the flat too. i have been hesitant to talk of this as who am i to tell the rusty stalwarts they are going the wrong way and why so many guys over the years have made attempts at tail flex? it works for dolphins because they are alive and have completly active flex. i was also worried about losing my technicakl advantage with Dru adler my air team rider (currently 5th on quicksilver air curcuit) Dru is 6’6"and 95kg (200lbs) all the guys above him in points are tiny guys and most of the waves the contest are in are 2 foot slop!. his boards with our flex/channel combo give at least 1 foot higher airs than tradional style boards in the same conditions! dave>>> I’m reticent to enter this discussion, because you are either ignorant of > the practical application of flex, or you are simple jerking your chain > while waiting for the Raider game to start.>>> Properly applied flex characterisitice in a surfcraft design is NOT a > theory. It is something which has been successfully applied for OVER 35 > YEARS. The only reason is is not the standard of conventional surfboards > is because the materials do not exists, in affordable form, which allow > for both controllable bending and bouyancy.>>> You seem to presume that drag and speed are at odds in surfcraft design. > They are not. Speed is the result is proper drag management. A dead > straight outlined, flat rockered board with minimal induced drag would be > limited in it’s speed potential in most wave conditions. The lack of drag > would force the craft down to the base of the wave, where little usable > power exists. When drag is introduced in the proper manner (I won’t go > into the details of that here, not enough time) the track of the board > becomes more parallel…utilizing the power of the wave more effeciently. > Practical application has proven this time after time after time.>>> A dramatic indication that drag can and does result in greater speed: look > at thrusters surfing a wave like Kirra. They enter a long tubing section > low, make seemingly unmakable section after section, and exit the tube at > a higher wave altitude than they entered. All of this was the result of > the drag induced by the outline, rocker and outer fin toe-in. The board is > allowed to find the most effecient track along the upper portion of the > face BECAUSE OF DRAG. A flatter, straighter board would wash out and run > down the face and be passed by…regardless of who was riding it.>>> The concept of flex does not presume to say that if we were to take that > same thruster and introduce flex it would be faster or turn with more > accelleration. What it does presume to say is that if we were to remove a > degree of the induced drag (say, flatten the rocker line and outline > curve) and re-introduce that drag with flex, then the drag would be > variable…less when the rider is unweighted and trimming, more when the > rail and tail are loaded up in a turn. Both situations would result in > more effective use of drag. (A board with tail flex can turn with greater > accelleration because more of the rail line can be loaded up in a turn > without rider hesitiation. The “smoother transition” you speak > of in snow boarding applies to surfing as well…and on the right board, > can result in a dramatic increase in speed.)>>> Another way to look at drag as a source of speed is to break down the > misconception that “lift” is soley the result of planing > effeciency. Lift, in surfcraft, is generated by two things: Planing over > flat water (like a water ski), and wave face elevation. Drag is what > allows a board to be “lifted” off the base of the wave and into > the more powerful mid-section. A board with no induced drag would plane > easily, but it could only run along the base of the wave. “Lift” > generated by drag is needed to pull the craft away from the dead water > along the base and into the power higher up the face.>>> So, a combination of planing and drag-induced lift are needed to reach > speed potential. Drag management…that’s what good design is. And, flex > has a viable place in that combination.>>> Again, I seem to speaking in theory. I am not. I have had access to and > ridden, FOR DECADES, the entire evolution of George Greenough’s kneeboard > collection. I’ve experienced first hand the transition between a solid > balsa kneeboard and that same board (via molding) as a flexible,torsion > stressed form. The difference in both trim speed, accelleration in turns > and directional manueverabilty is astonishing. http://www.feraldave.com
Dave when you say channels you mean full channel??? doesn’t it effect flex?? The carring of flex thru the middle of the board is my focus more then any other part of the design… As you brought out in small mushy waves your rider is getting a foot more air. Just what i’m looking for the snap that flex will offer a small light board… How many boards has Dru broke???>>> well, flex has been toyed with for many years, unbeknowing to many… > flyers, flutes,fin systems & placement, concaves and channels have all > affected performance both thru drag and drive (generally percieved and > accepted) but these additions also affected flex. im actually doing the > opposite to rusty and cj with stopping the flex at the tail and increasing > further forward! we have found flex in the tail for powerfull waves and > solid surfers to be slow turning.flex tails seem to unload way to early in > a solid turn creating unwanted drag 3/4 way thru the turn. having channels > in a quite flexible glassing combo (stringerless) actually increases speed > thru turns and makes for much better drive on the flat too. i have been > hesitant to talk of this as who am i to tell the rusty stalwarts they are > going the wrong way and why so many guys over the years have made attempts > at tail flex? it works for dolphins because they are alive and have > completly active flex. i was also worried about losing my technicakl > advantage with Dru adler my air team rider (currently 5th on quicksilver > air curcuit) Dru is 6’6"and 95kg (200lbs) all the guys above him in > points are tiny guys and most of the waves the contest are in are 2 foot > slop!. his boards with our flex/channel combo give at least 1 foot higher > airs than tradional style boards in the same conditions! dave http://surfnwsc.com
we have found flex in the tail for powerfull waves and > solid surfers to be slow turning.flex tails seem to unload way to early in > a solid turn creating unwanted drag 3/4 way thru the turn. Remember Dave, Greenough introduced tail flex into boards with THREE FEET OF DEAD STRAIGHT ROCKER in the tail of his boards. Take a yard stick and lay it along the bottom of any Rusty you have access to. Imagine a board as striaght as that yardstick along the bottom. THEN image flex introduced into the tail. I doubt anyone fooling around with flexible tails on surfboards today begins with anything nearly as straight as that yardstick. No wonder there is unwanted drag 3/4 of the way through a turn…there was too much rocker to begin with. To gain anything from flex, you have to start fresh with variable rocker in mind. Modifying existing designs with tail flex rarely results in anything worthwhile.
Dave when you say channels you mean full channel??? doesn’t it effect > flex?? my channels run from tail to 24" up from and yes they stop the flex in the tail>>> The carring of flex thru the middle of the board is my focus more then any > other part of the design… As you brought out in small mushy waves your > rider is getting a foot more air. Just what i’m looking for the snap that > flex will offer a small light board…>>> How many boards has Dru broke??? none for 9 months
we have found flex in the tail for powerfull waves and>>> Remember Dave, Greenough introduced tail flex into boards with THREE FEET > OF DEAD STRAIGHT ROCKER in the tail of his boards. yes but greenough was riding kneeboards the desired flex caracteristics are completly different !>>> Take a yard stick and lay it along the bottom of any Rusty you have access > to. Imagine a board as striaght as that yardstick along the bottom. THEN > image flex introduced into the tail. I doubt anyone fooling around with > flexible tails on surfboards today begins with anything nearly as straight > as that yardstick. No wonder there is unwanted drag 3/4 of the way through > a turn…there was too much rocker to begin with.>>> To gain anything from flex, you have to start fresh with variable rocker > in mind. Modifying existing designs with tail flex rarely results in > anything worthwhile.
True, kneeboards and surfboards are a different dynamic. But to dismiss tail flex as unworkable for surfboards only means you started with too much tail lift before you started introducing flex into the design.
having channels > in a quite flexible glassing combo (stringerless) actually increases speed > thru turns and makes for much better drive on the flat too. i have been > hesitant to talk of this as who am i to tell the rusty stalwarts they are > going the wrong way and why so many guys over the years have made attempts > at tail flex? it works for dolphins because they are alive and have > completly active flex. i was also worried about losing my technicakl > advantage with Dru adler my air team rider (currently 5th on quicksilver > air curcuit) Dru is 6’6"and 95kg (200lbs) all the guys above him in > points are tiny guys and most of the waves the contest are in are 2 foot > slop!. his boards with our flex/channel combo give at least 1 foot higher > airs than tradional style boards in the same conditions! dave Dave - of course - the channels would stiffen the glass on the bottom (like corrogations in roofing iron) so the rest of the board (ie the bit under the front foot) would flex more. I don’t get the flextail thing either - a bit more flex under the front foot, coupled with a flatter rocker was what I thought folks would have been shooting for.
Dave - of course - the channels would stiffen the glass on the bottom > (like corrogations in roofing iron) so the rest of the board (ie the bit > under the front foot) would flex more.>>> I don’t get the flextail thing either - a bit more flex under the front > foot, coupled with a flatter rocker was what I thought folks would have > been shooting for. i know what paul means about flat rocker combined with flex tails that seems to be the way he is travelling! i guess my tangent is different. my search has been for high speed and vertical drive! and to that end i have been developing the strigerless with tail channels to acomplish that. so far so good but we want more… http://www.feraldave.com
I’m not thinking clearly after reading all this. I actually posted twice > due to the scrambling of my brain cells. Chris, please go out now and > catch some waves. Grant dude , Caught waves yesterday morning and this morning, longboard at Moss & Carmel beach. Thanks for the headsup. Hows yer brain cells?
“…make this work better, then flex means nothing.” Carefully study the world around you… without active flex, much of nature would literally be nothing… including those waves you like to ride.