jondrums

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    jondrums
    Participant

    PS. would anyone like to purchase a stock Takuma tail?

    jondrums
    Participant

    All the retailers want to sell a wing/tail combo as far as I can find. When they value the tail over $200 and there is next to no resale market for the Takuma tails, that’s a non-starter for me.

    jondrums
    Participant

    I did this too one time. Couldn’t tell the difference. I support the effort though because the physics say it will make a difference. An aero/hydrodynamicist suggested to me that the most important part as far as surface finish is on the topside of the wing from the leading edge to about halfway back the chord. Surface imperfections aft of that or anywhere on the bottom side doesn’t really impact lift/drag. Same goes for the mast (leading edge to halfway back) and tail (leading edge to halfway back on the bottom side)

    jondrums
    Participant

    is it even possible to buy just the 1210 front wing?

    jondrums
    Participant

    I’m with you – I’ve always found ways to break things in ways that nobody else seems to.

    Interesting to hear you’re fine catching waves on 32L at 220lbs. I’m just a hair under your weight and struggle with a 40L – but that board is 2 years old and the box is in the wrong place. Looking to get something new and really not sure whether I need more volume or whether getting a properly laid out board would allow me to go down in volume.

    jondrums
    Participant

    some of the board makers are saying that the option to add strap inserts adds a pound! way too much. install your own when you know where you want them for like a tenth of that. The NSI mounts work great, but its probably nominally lighter to sink a few inserts and glass over it yourself.

    I think a lot of the track boxes are much heavier than they need to be. Builders are incorrectly equating burliness of the trackbox itself with burliness of the board. I think a light track box correctly bonded into dual stringers is the lightest and strongest construction method.

    Also, all of the trackboxes I’ve seen are deeper than they need to be. Look at the new carbon stick-on foil-mount. It has slots that are much lower profile, and also insert nuts to fit. We could shave some grams that way if someone would make a thinner slot low profile foilbox. Admittedly, weight over the foil mast is a lot less important than swing weight.

    So – swing weight.

    I think this is the main reason why people say short boards pump better. The rotational inertia of the board (swing-weight) goes up by the SQUARE of the length. (of course this ignores shape effects – a shorter board with a full nose could have more swing weight than a longer board with a fine nose).

    I propose an experiment to determine if what we care most about is weight or swing-weight. Next time I have some spare time I’m going to bring my board out to the dock for dock starting and try it with and without a 1kg mass added right at the center of gravity. I’ve been wondering about which is more important for too long.

    jondrums
    Participant

    The NL wings are very sensitive to tail pitch. Try various shims. I found 2deg up on the tail versus the pitch of the front wing to be perfect for me. 1.5deg was noticeably different, but impossible to see the difference visually. You need to use a digital level. The NL works fine with the GoFoil flip tip tail

    jondrums
    Participant

    The 15″ works super with the NL220. I’m sure it would be great with the GL and the 190 as well, but I haven’t run them yet. A big upgrade from the 14.5″ flip-tip GoFoil tail. I’m running it at the same angle.

    jondrums
    Participant

    how are people getting these tails? can they be bought online, or is it just through instagram

    jondrums
    Participant

    And this comment is a bit off topic. Maybe some of the guys who do a lot of pumping have noticed it. Pumping is quite a bit easier in glassy conditions! I’m not sure why.

    And for flatwater pumping (dock/rock starts) I’ve noticed that pumping is easier when there is no wind versus some or a lot of wind. I’m guessing the wind sets up a little bit of motion in the top layer of water. When we move the wing up and down it goes in and out of that moving water. Pumping is easier into the wind – I think we get a “water speed” boost at the top of the pump from the water in motion. And for sure pumping is harder with the wind in flat water – the wing has a slower “water speed” at the top of the pump. I’ve done some experimentation and have confirmed these effects several times.

    All this with the GoFoil GL wings

    jondrums
    Participant

    I have personally experienced two types of “ground effect”
    1) when very high in the water pumping gets much easier. I think this is a combination of two effects. First is that the mast has a lot of drag and getting high in the water minimizes how much mast area is in the water creating drag. Second, the wing works on differential pressure – pressure below the wing is higher than above. Pressure below the wing should be pretty similar no matter how far from the surface we are because the wing is compressing the water underneath to create that pressure. But the pressure on the top of the wing depends on the weight of the water above it. When we get high, there is very little water above it so pressure is low. That makes the differential pressure higher.

    2) the other kind of ground effect is when pumping in really shallow water. I’ve only felt it in water that is shallow enough where I would ground out if I didn’t stay high enough. But in this case I’ve noticed that pumping is dramatically easier. I guess it is probably because the water below the foil has nowhere to go and the pressure below the foil is higher than normal.

    jondrums
    Participant

    the leash idea is perfect – it goes into the category of “why didn’t I think of that!?!”

    jondrums
    Participant

    I put a lot of thoughts on this topic into a thread I started here. Some of those tips might help. Surfcowboy, you might not need more time in waves, dockstarting is what taught me to really be able to pump – prior to that it was hard to get enough attempts in the right conditions to figure things out (coming out of the back of a wave into variable conditions). Starting off a dock lets you control perfect flatwater conditions without any disturbance or wind or currents, or foamed water, etc.

    jondrums
    Participant

    what tail are you using with the GL180?

    jondrums
    Participant

    I’ll make an updated post on the One foil board I got in the mail earlier this month. I just got out on the water with it and am 2 sessions in. Its 107L and paddles like 107L (pretty tippy for me). Its under 14lbs with tuttle+slots+footstrap inserts! Construction is absolutely beautiful. The shape is working great for touchdowns and weight is great for turns and pumping but it is pretty sluggish to get out of the water as compared to other boards I’ve ridded that have a flatter wider front end. Scooped deck holding water may also be a contributing factor. Its a sweet board, and I do wish I had about 10 more liters for stability, which would probably get it out of the water much easier too. I’ll report more when I get a few more sessions.

Viewing 15 replies - 1 through 15 (of 38 total)