rodndtube.com's (OLD) MyPaipoBoards Forums. Reading but no posting on the OLD forums.

Solo

http://www.hisurfadvisory.com/stuff/gilbert.htm

Michael Lulham · Joined: 30 Jun 2004 Posts: Location: Newport Beach

I have believed for a long time that a hydrofoil should be my next step in boarding. Anybody know where I could get one made or learn how to make it.

Poobah · Posted: Thu Jul 01, 2004 4:44 pm Post subject: Hydrofoil

Here's Terry's kelp cutter
http://www.rodndtube.com/paipo/hydrofoil/paipo_hydrofoil.shtml

rodndtube · Posted: Thu Jul 01, 2004 6:30 pm Post subject: Re: Hydrofoil

Nels · Posted: Thu Jul 01, 2004 8:21 pm Post subject:

Check anything on this index page with the name "Wayland" ...there are several of Roger's hydrofoils featured including an early one post-construction but pre-paint so you can get an idea about how he makes them out of materials readily available at any home improvement store.

http://vagabondsurf.com/PaipoHome.html

It's a quick and fairly cheap way to try the concepts out.

Poobah · Posted: Sun Jul 04, 2004 12:37 pm Post subject:

How about just a little lift? Hydrofoil Fins?

RoyStewart · Posted: Sun Jul 04, 2004 3:31 pm Post subject: Hydrofoils

Hello Poohbah,
You have raised an interesting subject. The Pure Tunnel fin has great
potential for paipos and kneeboards because:

1) It offers no rail to rail resistance at all. This is an obvious
advantage for prone riders because no leverage is required to get onto the rail
and lightning quick turns are possible with no hang up from a deep fin.

2) Prone riders and kneelos are in a better positon to control the trim
angle of the wing. The tunnel is a wing with a lot of lifting power and the
board can project itself out of the water in a flash, so it needs to be
controlled.

3) The Pure Tunnel fin provides tremendous holding power at high speed
but can do controlled sideslips at lower speeds, just like a bodyboard

4) The Pure tunnel fin is the slipperiest fin configuration possible. Most
drag comes from tip turbulence, and the tunnel has no tip. It is using the well
known and proven aeronautical principle of the annular wing.

Have I built any Paipos recently? Well not exactly, I am a 'closet' kneelo
and recently built a wooden 'spoon' kneeboard along the lines of an early
Greenough spoon. My plan was to build a pair, one with a tunnel and one with a
single fin. I rode the singlefin version and sold it to a surfing museum (along
with three of my wooden longboards) because I needed the bucks, and now the guy
who owns the museum has closed it and I can't get a picture of the kneeboard.
There's a picture from inside the building on my site. The kneeboard is very
pretty. It has an inch thick chambered redwood and Paulownia bottom with
chambered cedar rails ( the rails being raised up )
I have got some Pacific and Western red Cedar here I could easily build the
tunnel version which I imagine could be used prone. Of course I could publish
some plans also if you want to do it yourself.
There are one or two details about fin setup that I can help with if you
want to stick one on another board.

All the Best, Roy 'Bowser' Stewart

PS Don't muck around with straight winged hydrofoils they are a bummer
_________________
www.woodensurfboardbuilder.com

RoyStewart · Posted: Sun Jul 04, 2004 3:55 pm Post subject: hydrofoils

I should add that you can make a hydrofoil tunnel fin out of a piece of plumbing pipe which comes in various handy sizes. try eight or ten inch. Of course it has to be foiled, but only on the outside. Try to set it into the board rather than glassing it on with fillets.
Over the past five years I have built many straight winged hydrofoil boards including some massive ones and boards with twin in-line foils. They all lifted and cruised ok but have limited control and will twist you off the board in the tube. Also straight wings have tips which are a major source of drag.
Go for the Tunnel!
Regarding the size of the foil, it is not necessary to have a big one. Foils generate lift exponentially as they go faster so once you are gaining speed the effect snowballs. The idea is to go fast which does not necessarily mean lifting right out of the water, either.
Iv'e got to go now see you soon Roy.
_________________
www.woodensurfboardbuilder.com

baidarka · Posted: Sun Jul 04, 2004 5:34 pm Post subject:

Hello Roy,

Splendid insights...now spawning inspiration. Aside from the foil of the tunnel, what do I need to know about angle of attack, when mounting?

Also, my belly sliders tend to have very wide tails. Will I have to pull in the outline to effectively use this arrangement?

-Seamus

RoyStewart · Posted: Sun Jul 04, 2004 6:19 pm Post subject: Tray riding with hydrofoils

Hello Seamus,
Regarding angle of attack, the most reliable way to go is to set them up parallel to the bottom. Your actual angle of attack while waveriding is determined by the angle of the whole board, so you control the angle of lift with the board. In fact because hydrofoils generate lift it is often assumed that you have to point them upwards, but actually most of the time they point downwards, just like a glider, with a glide ratio. When your glide ratio is flatter than the angle of the wave face, you are then lifting relative to the wave face while still pointing slightly downwards for speed. that's when you start to fly. Once you are flying you can then pop upwards, just like an aircraft.
Ideally you want to have your foil parked as close to the rail as you can, so maybe pulling the tail in is a good idea. A large foil can be used ( I have used them up to ten inches in diameter). In fact a big foil has more holding power, while still being able to sideslip at slow speeds. A little foil will only hold in when going very fast, and will sideslip a lot. You can tune them to the way you like it.
The length of the foil is also a factor, a narrow foil will bite in and start tunneling the water earlier and will accept water flowing in from the side more easily. A narrow foil will also have a gentle transition from forward tunneling motion to sideways drift, so you can push it around and control your sideslip/forwards motion factor.
I am offering carbon fibre foils via mail on my site soon if you want one let me know.
Roy "Bowser' Stewart
_________________
www.woodensurfboardbuilder.com

baidarka · Posted: Sun Jul 04, 2004 11:01 pm Post subject:

Roy,

I'm excited. I already started compiling materials to begin my first fin. Using stock on hand, I decided to lay up some thick veneers around an old cylindrical bucket (10 inch diameter).

A minor avocation of mine is playing with aeronautical toys (especially boomerangs). While reading your testimonial, two came to mind: the X-Stream glider and the X-Zylo flying cylinder. Both are capable of amazing flights and seem to follow principles similar to your designs. Check them out:

http://www.iwatoyco.com/technology.asp
http://www.xzylo.com/learn_dev.html

Take care,

-Seamus

Poobah · Posted: Mon Jul 05, 2004 12:51 am Post subject:

Poobah · Posted: Mon Jul 05, 2004 1:08 am Post subject:

Dead link removed.

RoyStewart · Posted: Mon Jul 05, 2004 3:18 am Post subject: tunnels

Hello Seamus, It's funny that you should mention those annular wing flying toys, I actually got off the straight foils and onto the pipe first by finding two 'flying gyroscope' (spinning pipe) toys at the beach and then seeing a 'hoopskirt' model aeroplane in popular mechanics. They fly really well and use a zero angle of attack. Go for it. Roy
_________________
www.woodensurfboardbuilder.com

RoyStewart · Posted: Mon Jul 05, 2004 3:25 am Post subject: foils etc

Hello Poohbah, I like the look of that spitfire board. I'll have to get busy. Scalloped trailing edge could be good. Two pipes could work but it might be hard to pull the outside one out of the water, they hang in very hard at speed. A tunnel is just a bottom concave that goes all the way round. Tunnel fins work better with a single concave. I always try to bend a concave in when laminating the bottom. All the best, Roy
_________________
www.woodensurfboardbuilder.com