board design and performance

> 10 years ago
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brady
brady
TAS
455 posts
TAS, 455 posts
23 Nov 2005 3:35pm
There seem to be a only a relatively small number of variations between kite boards, barring bizarre shapes etc.

These are
1. length
2. width
3. shape - ie width at tip vs middle
4. rocker
5. rail
6. shape of base - concave/convex etc
7. flex
8. number and position of fins
9. size of fins

I'm talking twin tips rather than mutants or surfboards.

So how do each of these impact on performance?

As I understand it
Length - likely to increase speed, but decrease maneouverabiility.

Width - for a given length, an increase in width will increase the bottom end performance. In my experience, a wider board is sometimes harder to hold an edge on.

Shape - width at the tips might decrease potential for nose diving?

Rocker - I know what it is, but have no idea of the effects of changing it. And is a relatively flatter mid section with more curve towards the tips an advantage?

Rail - a thin rail holds an edge better, but is maybe a little less smooth on the transitions? Not sure about this one

Shape of base - a concave base gets planing earlier. A convex base is a waste of time. Sunny shapes like bi-concave may have a bit of an advantage in the waves, combining early planing with improved maneouverability.

Flex - more flex = more pop. Probably would increase the wind-range of your board at the top end. I reckon it might be more forgiving in the chop but not sure about that one. A stiffer board will give better bottom end performance, but hurt your knees more.

Number, position and size of fins - I've decided I like the feel of boards more if they have bigger fins on. I feel like I have a lot more control, can hold the edge a lot better and get a bigger pop. So what are the advantages of smaller fins?

I'm pretty sure that at least some of the above would normally be found obn the floor of a stable, but just not sure which parts. Any feedback would be appreciated.

Cheers
Ben De Jonge
Ben De Jonge
WA
819 posts
WA, 819 posts
23 Nov 2005 12:44pm
My brain hurts.
eightfootplus
eightfootplus
NSW
298 posts
NSW, 298 posts
23 Nov 2005 11:42pm
you forgot the most important design variable,

colour,

just remember that red boards are faster
gruezi
gruezi
WA
3464 posts
WA, 3464 posts
23 Nov 2005 8:55pm
That's brilliant Brady. Surely someone could figure a way to enter the variables in to a program...and then people could order custom boards right off the web........FN brilliant www.cardboarding.com/ a great innovative aussie company....model can be improved on especially using the great minds here on this forum.............

Enough about kites, lets get in to boards.....nice one Brady.

Matthew
Matthew
WA
17 posts
WA, 17 posts
23 Nov 2005 10:26pm
Hi Brady,

Did you end up making that board? How did it turn out?

CARBONINIT
CARBONINIT
WA
48 posts
WA, 48 posts
24 Nov 2005 4:28am
Brady Upturn tips and fins ! Quattro rails! More rocker ,easier to carve but slower Dont go wider than 380 .Thin rails hurt ,dont go thinner than 2mm Top and bottom of board have to work together.Concave is slower as the water has to travel further.Flex is good ,more forgiving.Hard is fast. x4 fins as far out and as far back ,leave 5mm at the back. 55mm size fins are the norm for us.More forward = tighter feel board. Stable ,good for horses.Build enjoy.
CARBONINIT
CARBONINIT
WA
48 posts
WA, 48 posts
24 Nov 2005 4:29am
One major factor MATERIALS .Thats for another day!
brady
brady
TAS
455 posts
TAS, 455 posts
24 Nov 2005 12:06pm
quote:
Originally posted by Matthew

Hi Brady,

Did you end up making that board? How did it turn out?




Yeah, the board is absolutely primo. In flat water it absolutely cranks. Points upwind like you wouldn't believe, and holds an edge really well with a great pop. Behaves really well in the surf. It has a wider wind range for any kite than my other boards - the bottom end is better than my switch 135 (despite being much shorter -122), but can hold it to much higher winds.

Unfortunately a bit of a pig in the chop. Has a tendency to dig the nose. You end up using so much back foot pressure to stop this that it feels uncomfortable. But who wants to kite in the chop anyway?

Upshot is, if I go out at Cott, it's not too good. But the river, Cervantes or Gero, then it's my favourite board.

Soon to start on my next one, hence this thread trying to get some more ideas about what effect different changes have. I'm thinking of going for a 142, fairly wide, stiff mid section with flexy tips, wide rail, concave base and quite large fins
bushman75
bushman75
WA
3 posts
WA, 3 posts
24 Nov 2005 9:25am
Hi Brady, sounds like you've got some pretty good boards happening. I'm interested in the materials you're using (are they woodies? woodie/foam sandwich? or...). Any details would be great, I'm sure there would be a few others out there interested in making their own boards. Cheers
brady
brady
TAS
455 posts
TAS, 455 posts
25 Nov 2005 12:50pm
quote:
Originally posted by bushman75

Hi Brady, sounds like you've got some pretty good boards happening. I'm interested in the materials you're using (are they woodies? woodie/foam sandwich? or...). Any details would be great, I'm sure there would be a few others out there interested in making their own boards. Cheers


I have chatted about this stuff already, but love to do it again!

Divynicel foam core - two layers with diagonal braces of unidirectional carbon in between.

Cut to shape and shaped using sander - including concave base.

Unidirectional carbon to base, then 6oz crow's foot weave glass wrapped around rails. Vacuum bagged.

Cut foam on top, using router, for inserts for handle and foot straps (plastic inserts from some shop in Claremont - if you need the details I can let you know)

Kevlar under heelside part of foot pads for impact resistance.Carbon fibre over edges of inserts. Strips of unidirectional carbon - predominantly between foot pad areas, the spot most at risk of breaking if yo come down hard from a jump. Glass over the top, but only wrap the rails - not onto the base. Best bet here is to use masking tape on the base first, so the glass doesn't have to be perfectly cut/positioned etc. Then when dry it can be trimmed with a Stanley knife. Vacuum bag.

Bog to all outer surfaces - gives you something to sand.

Sand.

Paint. I've been using car touch-up paint. Bigger range of colours etc, but not at robust as marine paint. Other advantage is being able to spray without specialised equipment. DO NOT USE ACETONE ON CAR TOUCH UP PAINT. It dissolves it.

If you need any more information, I'm no expert but happy to help if you want

B
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