Jump to content

Recommended Posts

Posted

so.... what dimensions, rocker, flex should i do for the light wind coffin lid.

so that i kite in the ocean with swell, small waves and chop in light wind. So i need something to churn through that mess without bogging down.

  • Replies 38
  • Created
  • Last Reply

Top Posters In This Topic

Posted

Take a look at the Nobile Flying Carpet.

Near zero rocker, tiny concave bottom, rounded tips, hidden jet thrusters = win!

I think the general idea is to make it about 150-155 x 46-50 depending on your weight and requirements.

Posted

i'm open minded at this stage. maybe 148-45? i really haven't done much research yet.....

i think wider is better than super long, not much camber and fairly stifff. however i thing i need flexibility for my choppy small wave conditions.

Posted

Agree, make it wider rather than longer. My 170x51cm board is a handfull to get it going because you can't point it down wind to start off with, but you get used to it. Make the sides much straighter than my Barndoor2011, look at the vid to get an idea -- this is assuming a no fin board. I would go more for the Plank2005 profile (look at one of my recent vids, this is the shorter narrow plank). Rounded ends, hmm I'd go for straight ends, this has worked pretty well, but maybe for chop rounded may better. Throw the fins away, you don't need them, you don't want them, this is all to keep the drag down.

Rocker and concave, well that all depends on how you make it. If you're just jointing up some stock standard 19mm pin board, don't worry about rocker and concave, keep it flat, much easier to build that way, the only rocker is 5cm or so at the ends. If you are laminating the board, oh dear that will take ages, but then you have the choice.

If you are going to joint up a pin board, make sure you use resin to glue it, all the other glues are not water resistent. Don't think marine laquer will save the day when using glue not meant for marine applications --- eventually some of that laquer will wear off and the water will make its way to the glued up joint leading to delamination.

For the foot pads, go simple, just drill holes right through the board and counter sink on the bottom side, then put counter sunk screws in with nylocks. Never had a failure yet, never had a loose faster yet.

Stiffness of the board, well the 19mm planks are stiff and you need to take up the shock by bending your knees. I also means they can take huge loads if the wind picks up and will shoot up wind well. Sure some added flexibility would be nice, but then you're looking at laminations, up goes the build time.

Norman.

Posted

cheers men. good info. yes i like the noble board koma.

SB i'd be making it from ply or bamboo laminated together. probably about 8-10mm thickness with glass for extra stiffness.

PS i always use west system epoxy resin fro all my glueing and g;assing requirements.

Posted

after a bit of interweb brousing i have discovered that big barn door style rectangular boards are great in light wind until it gets choppy then they are poo.. this leads me to a problem where i only have choppy,swelly poo..... hmmmm. i wonder about a bigger wave style mutant like the FS flywave would be better than a barn door in my conditions?

what are your thoughts

Posted

after a bit of interweb brousing i have discovered that big barn door style rectangular boards are great in light wind until it gets choppy then they are poo.. this leads me to a problem where i only have choppy,swelly poo..... hmmmm. i wonder about a bigger wave style mutant like the FS flywave would be better than a barn door in my conditions?

what are your thoughts

Define poo Plummet. Really, what are they saying? For my commercially made board the Cardboard it's one of the bigger boards, I was told it would not be that good in the choppy conditions at my local, well I have proved them wrong, I go out using it in all sorts of conditions of ultra smooth to ultra choppy + baywaves, I just manage to get the best out of the board. I reckon you will get all sorts of opinions (including mine :D ), in the end you just have to build it, try it and set if it suites your needs, then fiddle some more. Like my big BarnDoor, at first I was a bit disappointed, but now I'm used to it and get the most out of it.

Light wind + chop, I suspect you will not get that. Chop is created by wind and if the wind is light so will the chop. Perhaps for ultra smooth you need an offshore wind , but we all know of the dangers of trying that.

Posted

define poo... ;} spray in the face and unpleasant to ride in chop. i do get chop round 12 knots but its amplified by the swell at the same time.

So my research is revealing this

chop, waves, swelll require a board with rounded ends, and lots of rocker. (which i currently have)

light wind requires a stiff board rectangular shape with very little rocker.

So both requirements are at polar opposites of the spectrum.

another idea is rectanular shape with smallish rounded ends but flexible tips which would flex sort of give you an auto rocker when when required.

i'm still pondering.

Going to try this bamboo veneer

http://www.wovenbamboo.co.nz/bamboo-veneer-g-96.html

Posted

Plummet, I haven't tried this yet, but it's work in progress. Perhaps a unidirectional board is the way to go. Fat at the end, round and pointed at the front end. It will always be a compromise. With a unidirectionaly you (I) will have to learn to go toe side.

As for the spray, I wear sunnies (until I lost them today -- bugger) so spray does not matter. Spartan's helmet has a built in visor, it would keep out the spray even better.

Here is another thought, not a coffin lid, but ... since chop is the problem, why not one of those hydrofoils. The hydrofoil is under water, no chop there. When I read about them, they said they are only suitable for light wind. Don't know how well they go in the surf though, plus the whole new learning curve.

Posted

I too wear sunnies.... as for a directional. I already have a surfboard. But i do have a problem in that i hate toeside with the wrath of 1000 circus monkeys. I've practiced many times but i still hate the side pull. it annoys me. So i'd prefer a TT for light wind. I'm leaning towards the rectangle shaped TT with flexi tips. I may not make it a full barn door but simply bigger than normal so it becomes a board Ok at light wind but also good when the wind picks up a little.

We have quite a few days that start off light then pull up to 16-20+ as the seabrease kicks in. some times it pulls up other days not.

Posted

PS i would love a hydrofoil even though it is directional. but my location has boulders subsurface that you can't always see. I'd simply tear the foil off on the boulders.

Posted

I would go with the bamboo ply 6mm...Now I'm thinking if I did that it wouldn't break since the bottom 6mm marine ply wasn't strong enough to survive a few m jump...The 0.6mm veneer is just to thin at bottom and it will brake first no matter how many layers are there. Didn't glass the bottom tho, so...

Other than that it was a great litewind board for myself being 58kg.

http://downunderbloghr.blogspot.com/

D.

Posted

I would go with the bamboo ply 6mm...Now I'm thinking if I did that it wouldn't break since the bottom 6mm marine ply wasn't strong enough to survive a few m jump...The 0.6mm veneer is just to thin at bottom and it will brake first no matter how many layers are there. Didn't glass the bottom tho, so...

Other than that it was a great litewind board for myself being 58kg.

http://downunderbloghr.blogspot.com/

D.

dbabicwa,

Enjoyed reading the update on your blog, sounds like you are very resourceful to get all the needed bits and pieces. So I take it you broke your board then? It's sure a long path to get that board of yours made and not break. As Joel said to me, it's a labour of love.

If your wood is breaking, then maybe you need more fibre glass layers, ie the glass provides the strength, the wood makes it pretty and acts to create bulk. For additional strength you need a larger total thickness. The outer layers take the tensile and compressive strength along the board, whereas the internal layers only take compressive loads (weak loads) perpendicular to the board surfer and take the shear loads (weak loads) between the top and bottom layers.

Though at the tips, the shear forces can be quite significant.

Regards,

Norman.

Posted

interestiong read. Yes next time you need to do a glass layer at the bottom.

I'll be running a thin bamboo board then re-inforcing with carbon or glass layers.

i'm a believer in unidirectional and double dias layers.

So... my through process thus far would be this

144 x 46 board

6mm vlam bamboo bottom then a couple of smaller 2.6mm bamboo fly layers on top to give a stiffer center section and more flexible tips.

I's plan a mild rocker. (not sure what mild is yet).

a layer or Double bias top and bottom to keep the vlam bamboo together and then uni directional layers until i get the appropriate stiffess.

Posted

Yes, it's broken in a straight line between the footpad steel inserts. Almost right in the middle. Interestingly, only a thin, first wood veneer cracked. Hopefully, a few glass layers would prevent this.

Unfortunately, took it for a ride in 20-25knts, for which wasn't designed for. 2-3m jump, landed dead flat. My bad.

Also, the 6mm bamboo ply is quite heavy, not sure how heavy your board will be!

If you like, I can measure my bamboo leftover and weight it to give you a clue?

Posted

Yes, it's broken in a straight line between the footpad steel inserts. Almost right in the middle. Interestingly, only a thin, first wood veneer cracked. Hopefully, a few glass layers would prevent this.

Unfortunately, took it for a ride in 20-25knts, for which wasn't designed for. 2-3m jump, landed dead flat. My bad.

Also, the 6mm bamboo ply is quite heavy, not sure how heavy your board will be!

If you like, I can measure my bamboo leftover and weight it to give you a clue?

Personally if my boards can't handle what ever I through at them, they fail the pass test. So if I can handle it in 20 to 25 knots then the board should be able to handle it. As for jumps and landing flat, well I think you need to make the board stronger, you can't always guarantee how you will land the board. Note your other option is to add more bulk to the board if making a new one, so some weaker (lighter) layers in the middle of the layup will make it stronger.

In simple terms your stress =

M*y/I

where M = bending moment. Take this as a constant.

y = distance from the middle of the board to the extreme fibre, if you have a symmetric layup, then y = half the board thickness.

I = moment of inertia = b*h^3/12

b = width of board, take this as a constant

h = thickness of board

With these two simple formulae you can easily and quickly see how much your stress drops as the thickness h is increased. For hollow sections the equation for moment of inertia is a bit different. Also if the stiffness/orientation of the layers are different, again the equations change. Hence why I said "in simple terms" to give a feeling for the changes.

What orientation did you use for the glass plies, how many plies did you use? 0 - 90 degrees or 35 - 135 degrees to the axis of the board for the top/bottom layer ? 0 - 90 would be strongest especially considering how you board broke. Often though the top and bottom layers are at 35-135 degrees so they are not the critical layer, then the next layer is 0 - 90 degrees. It's a way of protecting the critical layer.

Any way ....... how's it going Plummet, decided on your design, have you started building? Would be cool if you post some pics as you build the board. :popcorm1:

Regards,

Norman

Posted

Yes, it's broken in a straight line between the footpad steel inserts. Almost right in the middle. Interestingly, only a thin, first wood veneer cracked. Hopefully, a few glass layers would prevent this.

Unfortunately, took it for a ride in 20-25knts, for which wasn't designed for. 2-3m jump, landed dead flat. My bad.

Also, the 6mm bamboo ply is quite heavy, not sure how heavy your board will be!

If you like, I can measure my bamboo leftover and weight it to give you a clue?

did the board snap in half? or is it simply cracked? if cracked then its easily repaired. post up a pick and we can advise.

ps Even though i'm asking questions about board dimensions i am an accomplished board builder of longboard skate boards and landboards..... so i have the kiteboard building skills lurking.

Posted

SB I'm still formulating ideas in my head. I also want to ride some other gues standard rectangle boards first too before i make a decision on what to build.

i may end up building a normal size deck first....

in other news i'm also churning a longboard skateboard design in my head also. that one is tricky. intergrated base plates in the deck and carbon hangers with sipherical roller bearings. i'm not sure which build will comence first.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...