Diy sup foil

[TallDude]

I looked at the North kiteboard foil when I was researching foils. It does seem safer in more ways than one.

[supuk]

yea i was waring a helmet and impact vest today and i think that is a bare minimum for learning. The north one looks a lot safer just hope if you did fall on it it wouldn't brake it straight away. I think in time dw foils will evolve in to something quite different. It would be great to have a go on one that is a bit more refined so i know what I'm trying to achieve as at the moment i don't know how much is me and how much is the ghetto foil.

i changed the angles of the foil relative to the board as well as the incidence between the front and rear which seamed to help and i may go a little further still.

[JP4]

I ran into Tony Logosz down at the Event Site today as he was rigging up his foil windsurfer. He said he has a foil SUP that he's been experimenting with downwind here in the Gorge. His thought was that it might be a tough go foiling downwind in the Gorge since the swell is much smaller than the ocean, not to mention the weeds. It will be interesting to see how all this develops.
JP

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[surfcowboy]

Surffoils over on Sways uses the runner style. I was thinking that that, being lower too, might be good for an experiment. You could also probably mount it with 4 pro box boxes. You'd need a forward canard wing probably but I think it's an idea worth pursuing.

Ok, which of us is gonna start a prototype over here?

[supuk]

yes it makes a lot of sense after you start learning or should i say crashing . I wondering if putting some dihedral into the wings will help give a bit of stability, i think for sup it should be posable unlike kiting were the board is on a rail a lot more. Im also wondering if i have to much area on the foils and it would help going a little smaller.

so much to think about with it all it would be great to have others having a play and sharing there finding, there is so many thing to try.

[blueplanetsurf]

We have been practicing foiling behind a jet ski and yes, it is very tricky and you have to learn a whole new sport and muscle memory.  Kai makes it look easy but it is very tricky.  We also had some bad crashes and broke the mast on the foil.  One thing I learned is that your weight needs to be centered right over the front wing of the foil, so it looks like you need to extend your deck pad further back so your back foot is on top of the mast when foiling.  We ordered a hover glide foil from Slingshot to practice on.  You can get 3 different mast lengths so you can slowly work your way up to a longer mast which should be less dangerous and frustrating:
http://www.slingshotsports.com/Foil

[blueplanetsurf]

This is a pretty good introduction to foils:

[supuk]

cheers rob yes i should have put a longer pad on i was finding myself standing one foot on and one foot off. It would be interesting to know if the kite foils are the right sort of size for sup.

[Admin]

Why two wings on all of these designs?  It seems like one longer wing with no fuselage would simplify, reduce drag and might be plenty stable.

[supuk]

In aircraft terms a convential main wing and a tail stabiliser is far more efficient than what is called a flying wing.

[Admin]

In aircraft terms a convential main wing and a tail stabiliser is far more efficient than what is called a flying wing.

Is that not design specific though (horizontal stabilizer, directional pilot input, long fuselage requirement)?  It seems like most low power air designs (hang gliders, parafoils, kites) and some planes (Concord, etc) opt for a single wing.  Looking at many current foil designs it appears that a lot (most?) of the drag would come from elements other than mast and a wing (were a single wing to be used).

Of all the sports that foil, we have the lowest power to work with.  No kites, sails, jetski, and relatively little gravity assist.  It seems like reducing drag is a much bigger deal for SUP foils than the other sports.

[supuk]

Paragliders are extremely unaficient and hangliders are now using tails for stability so they can use a more efficient airfoil. To get the stability from a flying wing you have to have reflex in the foil which is unaficient in its self. One of the main things is to reduce the wetted surface area which is something a flying wing does not do well. Just take a look at the glide ratios between them all.

[Beasho]

Why two wings on all of these designs?  It seems like one longer wing with no fuselage would simplify, reduce drag and might be plenty stable.

A flying wing is the most efficient design, but they are almost impossible to control. 

Think B2 Bomber, they didn't make it to look cool.  However the older versions were called "wobbly goblin" because until modern computers were introduced they would flutter out of control.  The tail surfaces allow for stability on an otherwise unstable aerodynamic shape.  The high aspect wings on a glider are even more unstable requiring a sh-t load of computer stability or a simple long tail.

From Wikipedia:

A clean flying wing is sometimes presented as theoretically the most aerodynamically efficient (lowest drag) design configuration for a fixed wing aircraft. It also would offer high structural efficiency for a given wing depth, leading to light weight and high fuel efficiency.

Because it lacks conventional stabilizing surfaces and the associated control surfaces, in its purest form the flying wing suffers from the inherent disadvantages of being unstable and difficult to control. These compromises are difficult to reconcile, and efforts to do so can reduce or even negate the expected advantages of the flying wing design, such as reductions in weight and drag. Moreover, solutions may produce a final design that is still too unsafe for certain uses, such as commercial aviation . . . . But maybe computer control on a SUP Foil could be worth a try.

[Admin]

I wonder.  It seems like in our usage the flow from wing into mast around fuselage into tail wing would create more drag.  Especially with joints and hardware for portability.  Also we have the board (which in the air examples would be the fuselage) and then a second fuselage underwater (or a second mast for a second wing).  All seem relatively draggy.

[supuk]

like i say wetted surface area is a big factor as well. However i don't think the designs that are used for kiting will be what it stays as. it would be interesting to try something more along the line of the AC boats.