Litewave Twin-Tip Hydrofoil.

[Peter_Frank]

Snip...

Foils are about performance and speed, therefore efficiency. It is not hard to guess which kind of travel is most appropriate.

Disagree - every one for him/herself here. Some like performance and speed yes.

Hydrofoils are about agility and feel and smoothness for me (riding waves, carving, doing tricks), the very FEEL

And this is done with a directional, just like you surf waves with a directional (waveboard) also because of the very feel and ability to ride waves much better.
Even marginal wind kiting was done on freeride raceboards by almost everyone here, and not the old "doors" that dissapeared as boring and did not feel good, apart from having so little "performance" that they could not ride in light wind upwind very well, nor handle chop

When I was teaching I used directionals for the last seasons, as it is easier than a TT on these - you dont have to bend one leg "oddly" as it tracks the right direction itself smoothly - and you can ride less powered even doing mistakes in the powerstroke and it will still glide/float.

A directional got this drive and smoothness and carving ability that are not present in TTs

So TT's are great for freestyle, but the driving and gliding "Feel" is lost IMO, so I see these more like a skateboard or wakeboard - can be fun, but extremely different

I think it is great that new TT hydrofoil innovations are tested, maybe something ingenious will pop up noone had been thinking about, or maybe it will be a dead end - time will tell

I would say that hydrofoiling can be about performance and speed, or agility and carves - or both !

Peter

[ronnie]

I really wonder how these people decided that having a bi-directional boat was the solution.
Looking at the video I am quite sure that it would be much fast to turn the boat around than to move the mast around.

And I won't even get started on the fact that they have to kill every last bit of their momentum to get going in the other direction. And when they are done with that, they are now pointing 180 degree away from where they were heading, so not ideal for sailing upwind.


Obviously in kiting it is different. The kite has to be redirected anyways, and the board carries very little momentum, accelerates very fast, and change direction easily.
But from an efficiency point of view, it is always better to have one end that is meant to go forward.
Therefore if you're not bothered about efficiency, and what versatility instead, a twintip is the way to go.
For efficiency, you have to get a directional.

Foils are about performance and speed, therefore efficiency. It is not hard to guess which kind of travel is most appropriate.

As a non-foiler, I can understand that the current directional foil design brings new levels of efficiency - which is great.
From what I read it also can bring new sensations for carving and other movements, which make it attractive.

Twintip foils seem like a step backwards - and they are in terms of efficiency in either direction - but there may be something to learn from them.

I like Horst's investigation into the mono-foil, and I'm glad he is going to investigate the twintip foil.

The current, most efficient foils seem to be operating like most airplanes. The plane flies efficiently, but also, if it stalls, it will go into a steep nose-dive to re-establish flow in the right direction over the wings (hopefully before it hits the ground). The plane has pitch-stability, from having a rear wing that pushes down.
Consider this video.


Horst has been riding without a rear wing pushing down and without most of a fuselage, on the mono-wing - so he has reduced the drag and also increased the total lift for the same speed. He has lost the auto-pitch-stability.

Canard designs only push up. If you could use 2 Canard wings with 2 airfoils that worked together as the AOA was changed, to provide pitch stability, it would depend on how efficient the airfoils had to be when doing that, as to whether you could get a better lift/drag ratio than the current design of directional foil.

The other thing that is different from a plane, is that you are dropping less than a metre to the water surface and when you hit the surface, it is better to hit it tail first, sinking, than a nose first dive.

It may be that the twin foils are Canard designs, and they will not be efficient because they have to go both directions, but there may be something to learn from them.
My guess is that they will work better with the leading edges of the twin foils facing inward, and mounted on the underside of the fuselage. None are like that so far.

[Mossy 757]

My suspicion is that canards will be more difficult to ride in all but the lightest and smoothest sea states because their pitch stability prevents the rider from adjusting ride height to account for the irregular surface of the water, waves, etc. It seems like it would be more difficult to control a canard in the wave foiling domain (my favorite) without the ability to tip the nose over and "drop in" going very fast.

A canard setup might be ideally suited for air style since you could essentially load up the wings and accelerate to a designed takeoff speed in utter stability, allowing you to focus on timing and kite flying.

[foilonfoil]

..discussion with Dave a few weeks back and his design is dead - Difficult to ride and poor performance.

As most of us expected.
For the record, I think all of us appreciate it when people try new things.. even when they fail.

CG

Good on him for trying! In all product design considerations, the questions that drive innovation are
- What problem are you trying to solve?
- What compromises need to be made to solve the problem?

Dave was pretty clear that usability and performance sucked and there appeared to be no quick fix.

[foilonfoil]

The other thing that is different from a plane, is that you are dropping less than a metre to the water surface and when you hit the surface, it is better to hit it tail first, sinking, than a nose first dive.

Wing loading is going to dictate what wing stalls out first so for a canard design, weight distribution would need to be modified more to the rear so that canard wing loading is balanced appropriately across the smaller canard wing and larger main rear wing.

Main wing on a canard design would need to be placed close to where the front wing is on a regular foil. Almost be fun just to take an aluminum foil and reverse the direction of the fuselage and reverse the direction the wings are pointing.

[tahoedirk]

I think there was/is a quick fix. A degree or two of pitch on both wings and someone who can foil already, sometimes you need to invite and entertain outside input, not always though. Regardless , hats off for trying Dave

[plummet]

The person that says it cannot be done should not interupt the person doing it!.....

I always snigger when people get so wound out about something they think is worse than what they are doing..... Who actually cares what other people enjoy?

If someone wants a TT hydrofoil and it suits them. Then so be it. Let them have fun. Do not mock or belittle there enjoyment.

Will it be as efficient and fast as a directional high aspect hydrofoil? no it wont be. But if that's not the what that person wants then again, who cares?

I personally look at surfers bobbing up and down in the water and getting 30 seconds of fun every 10 minutes and think. What a waste of time. That's way too much effort and waiting for only a small amount of fun. Surfing is not for me. But for some people surfing is better than kitesurfing. They love to bob up and down in the water, the crave that super clean wave every 10 minutes and don't mind the high effort to low fun ratio.

Everyone is different and will enjoy different things.

At the end of the day he who is grinning the most is winning. If that's the guy on his new TT HF. Then he has go his moneys worth.

[Toby]

exactly plummet.

There were times when people thought what a crazy idea to have a foil under the board...

And now?

Let it be and enjoy.

[abel]

The person that says it cannot be done should not interupt the person doing it!.....

I always snigger when people get so wound out about something they think is worse than what they are doing..... Who actually cares what other people enjoy?

If someone wants a TT hydrofoil and it suits them. Then so be it. Let them have fun. Do not mock or belittle there enjoyment.

Will it be as efficient and fast as a directional high aspect hydrofoil? no it wont be. But if that's not the what that person wants then again, who cares?

I personally look at surfers bobbing up and down in the water and getting 30 seconds of fun every 10 minutes and think. What a waste of time. That's way too much effort and waiting for only a small amount of fun. Surfing is not for me. But for some people surfing is better than kitesurfing. They love to bob up and down in the water, the crave that super clean wave every 10 minutes and don't mind the high effort to low fun ratio.

Everyone is different and will enjoy different things.

At the end of the day he who is grinning the most is winning. If that's the guy on his new TT HF. Then he has go his moneys worth.

+1

[Europ2]

When I watch the latest Ierofoil video, I think I can cope with the "pitch instability".
It looks sooo promising that I think it could become the missing link between a gliding board and a very efficient directional KBHF.

If this novelty holds its promisses, guess what ? From Q2 2017 onwards, every new comer to hydrofoiling will not care which board arrived first. The TTHF will just become the "natural" first step to hydrofoiling for foil newbies and schools. Then, as during the pre-foil era (2007), +/- 60% will stay at this level and the rest (40%) will try the fascinating directional on foil. 50% of those (that is 20 more % overall) will go back to TTHF for miscellaneous reasons (scared, too difficult, no time to invest to master the jibe, ...)
To summarize, 80% will have a blast TTfoiling below 20 knots. The courageous 20% one's who will not fear the extra personnal investment will try to reach 25 then 35 knots.