Wing question (Not for Horton...)

[ral]

D3 fins have three positions for the wing. The one in the bottom of the ski allows the wing to be upside down (screws down) at about the same position than on the regular one with screws up.

 

The question is, what position would be more efficient? Looks to me that disturbing the flow between the ski bottom and wing would be worst than the flow from the wing down, so putting it in the bottom position would be more efficient.

 

Opinions?

[Horton]

As the wing moves down the fin, it offers less drag - more stability and impacts the arc of the end of the turn more.

 

[ral]

But in this case the wing would be basically in the same position, the only difference being that the screws and protruding support are nearer or farther away from the ski bottom.

[Chuck_Dickey]

If the screws are below, the foil is closer to the bottom of the ski and the same wing angle acts more like a brake. If the screws are above the foil is lower or farther away from the bottom of the ski and acts more like a stabilizer. Just as JHT stated, "impacts the arc of the end of the turn more."

[DW]

My opinion would be that the mounting surface / protrusion mounted above or ski side would lessen the efficiency of the wing section that would maintain the same angle and location. The reason is that there is now less effective surface acting on the flow between the ski and wing section. To negate the effect of the disturbance now below the wing would be to add some depth. If the wing surface is not situated in the same position on the fin, this comment is not valid, but I think that is the question you are asking.

 

I use a thin stainless wing and do notice the difference in effectiveness based on less mounting area thickness, the wing is basically more efficient and can be run at less angle to create the same drag force.

 

I think both John and Chuck are actually answering a different question than what you are asking and thier answers are correct for a different wing position on the fin itself.

[ral]

@DW, you got it.

 

I will try putting it below with the screws down, and will see if I notice the change.

[Chuck_Dickey]

yes, now that I reread the original question, I agree with DW. Please post your opinion after you try ski it in both positions.