Beiträge von RazeR69

Back to the Virus Foil which is the title of this thread. They have sent me specs on their foil fin. The most interesting and astonishing one is the wing set at a minus 2 degree angle of attack. Now I've repeated over and over that AoA is NOT necessary for early planing, and in fact hinders early planing. But surely negative AoA hinders early planing even more.

What it does is prevent the nose from "pearling" and indeed if you watch their video the nose is high up in the air! I suspect they are giving up some early planing for lift at higher speeds. By the time the nose is that high, the AoA will be at 0 or 1 degree.

My theory, as explained on another thread, is that NOT lift at the fin box, but frp forces are responsible for the nose digging in. frp as in forward rotational propensity caused by angle of attack trying to level out in the water. And frp I believe is reduced by having the wing further back rather than further forward as everyone else in the world believes.

Jus sayn'

Dr. Zak: You are preaching to a tough crowd!

Let me give you some tips IMHO ......

- If the fly-fin is best for everything, then it is the first fin in history to be. Every other fin has to be designed for 1 or 2 advantages: maybe top speed, maybe easy control, etc. How to pick one or two advantages?

- Ease of learning will never sell to any windsurfer already sailing. Give a couple to learn windsurf schools and get professional feedback from them. Maybe the son is just a phenomenal quick learner.

- Do not use a poor not windsurfer go to sell your idea to a good windsurfer. Use a recognized good windsurfer.

- As you are finding, it is very tough to show a real advantage with an honest video. And it is quite possible that there is not a lot of trust in a video.

- All these people at the Canadian Hole who have seen the fly-fins for themselves ...... Have they immediately bought a fly-fin and taken it back to Canada and write about it on the forums and tell their friends? Are they not that amazed?

- I have had great results with a fly-fin. BUT, I had to attach it to a proper fin to fix many, many problems. What it does for me is 3 things. Very low wind early planing, and / or 2 m. smaller sail, and excellent fin for gusty conditions. (probably because of that 2m less sail; I can start planing early and still handle the huge gusts.) At strong winds I suspect a normal race fin will be faster. And 1 fairly large negative - I have a new way to jibe. It does not do everything better!

Until now I never like smilies, but these are priceless! The head to the wall and the hammer to the head! Thank you.

Whatever. I have long since learned that with FRP the customer is always wrong.

I have freely admitted my lack of proof and my expected remedy:

Zitat

Now I have not proved this to anybody else except 7 or 8 kiters (former windsurfers) who were with me in Cuba, watched me sail, watched over my fin, helped me test my wind meter, etc. And otherwise there is general disbelief! Fair enough! In 2 weeks the conservation area where I want windsurf open and hopefully I want to be able to take some videos of my buddies, get GPS speeds, local wind read-outs, etc.

That does not mean I should waste more money on a design my intelligence and my testing tell me is still flawed. With exchange and sales taxes I paid $450 CAD for a useless fly-fin, three times more than I have ever paid for a fin. Yes FRP is very good about refunding money, but that doesn't get back the shipping and taxes. And more importantly, it doesn't give me a workable early planing fin which is now possible!

Dr. Zak, you and Dr. Lunin manufacture and sell fly-fins. You have every right to praise every single model as perfect. But I'm a customer who paid money for your product, and I have the right to praise or criticize that product as I see fit. When you sell a fin that works as well as I now know is possible, I for sure will praise that product as much as I have criticized the early models.

Thank you Dr. Zak. Here, some people are also impressed with formal education. Others are impressed with intelligence. These things do not always come together.

You misunderstand me on several counts. I am not asking for free fins for my friends. I am quite sure they will purchase fins when they see mine in action. Only problem is, FRP does not make a fin I can recommend.

I made my composite fin solely because FRP had no reasonable model to offer me. I was assured that models 2018 to 2020 were much better and would work for me. But I didn't believe it. And now of course we both know I was right. Cesar Ramon from Malaysia tested the 2019 model and "Deska" from Hatteras tested the 2020 model and they both rated them useless. I selected a fin of reasonable length, rake, area, stiffness, etc. to actually perform like a fin should and added the FRP wing to the bottom of it. With great success!

Now the 2017-700 model is a quick response to my success with a longer fin but sadly it is deficient, in my humble opinion, in 4 or 5 details that I have found important for a fly-fin to work. Since you've read all my emails to FRP you know the changes I think are important.

I cannot use your advise to "get a correct fly-fin for your board" because FRP's advise to me, to Cesar Ramon, to Deska, has been just wrong. I have spent a lot of time thinking and testing this idea. I am freely sharing my information and insights to the entire world; I am not looking to make any money, just to increase my own windsurfing enjoyment.

FRP started this whole foil-assist evolution up again. They have ingenuity, creative ability,

manufacturing expertise, material expertise, flexibility; possibly the only company on the planet able to evolve a new type of fin this quickly. And I am offering to help.

Dear Doctors, Dr. Zak, dr. Spin out, Dr. bfl, etc. etc.

My name is Ray Sauder, aka RazeR69, from Canada. My friends call me Dr. Dolittle sometimes, ha ha.

Still, as far as i know, i have made the most successful foil assisted windsurf fin with the help of dr. Lunin's wing. I have achieved early planing at 6 knots with a 7.3 sail. My board is on the tail, me hiked over the water in a normal sailing position. Everything performs beautifully on a tested 15 knots with zero spin-outs.

Now I have not proved this to anybody else except 7 or 8 kiters (former windsurfers) who were with me in Cuba, watched me sail, watched over my fin, helped me test my wind meter, etc. And otherwise there is general disbelief! Fair enough! In 2 weeks the conservation area where I want windsurf open and hopefully I want to be able to take some videos of my buddies, get GPS speeds, local wind read-outs, etc.

While I got very lucky with my first attempt, I do not believe it is yet the best possible. Hopefully I can get FRP to help me with another attempt, making 4 or 5 changes. If you have not read my results so far, read them here:

http://forums.boards.co.uk/sho…tails#UCBIzX2477Xqj3d5.97

Has anyone, anywhere, purchased a Virus foil fin and tested it out? Good or bad results?

I kept editing 7 cm. to the rear for the new position of the wing. The post keeps changing it to 7 inches which is wrong.

Hello: ;

Ever since foils proved Their worth, I've felt there must be some adaptation that would work to NOT bring the board right out of the water, but to give it some lift. To plane in lighter wind or with smaller sails or to make heavier sailors plane easier. By using a horizontal wing which could provide lift in both directions.

It seems clear to me that if the board is still going to sail on the water in a normal fashion, then the fin must retain all it's normal characteristics; enough area, enough length, enough backward slant, low drag, etc.

By theory the best lift is a low aspect foil shape; that is flat on the bottom and curved on the top. The greatest lift but the greatest drag is the angle of attack of that low aspect foil shape. In order to lift the board right out of the water, AoA lift is necessary to increase the amount of lift to the height of the board above the water. However, my experience shows that AoA is unnecessary for early planing and in fact hinders early planing. I use 1 to 3 degrees AoA only to ensure that mounting and tail rocker does NOT cause a negative AoA.

I purchased a FRP fly-fin and found it to be good lift but violated every norm of good fin design. I cut the bottom 4 inches with the wing and attached it to a 50 cm race fin. Eureka. It sailed wonderfully and planed early or with a 2 meter less sail! See all my results here:

http://forums.boards.co.uk/sho…tails#GZR1mfT3CGq6iagc.97

Never mind that the wing was now 7 cm. further to the rear. Everything worked! However much theory says the wing must be forward; it is just theory and wrong.