RE: trimaran plans
Good to see this still going. I am following along with all the builds and doing alot of research. I hope to start construction of my Tri in the beginning of May.
I have done alot of research on wing masts and even full wing sails for power. Anybody have expereince with either> As the Tri's can get going very fast, wing sails and wing masts can further increase the power and speed with higher L/D ratios. I am currently looking at low Re airfoils and flap geometry to see if any of this is possible. A high aspect ratio wing sail with a carbon spar and balsa/carbon ribs covered in iron on film would be quite light and would require less force to actuate than a conventional sail. 1 or 2 flaps at X% of the chord along with control over the rotation would serve to trim the sail.
The biggest problem I can see is airfoil deisgn. A section is needed that will operate well at low Re's and capable of a high angle of attack all while maintaining a high L/D ratio.
Hopefully if I don't have much school work this week I can begin a design for a drop in replacement wing sail for the Tri that Idealist has provided.
Another idea I was thinking about was a T-foil in the rear. I have seen this on model Tri's to prevent the bow from going under. All examples I have seen, however, are fixed foils to provide a downforce.. you can't control the amount of downforce. My idea was to have a foil with variable angle of attack (fully flying) actuated by a small servo.
So for example, if you are running with the wind, you would pull back on the pitch control (elevator for aircraft). This would actuate the foil and provide more downforce by reducing the angle of attack. An active foil, similiar to how some hydrofoils maintain pitch stability.
[link=http://www.mathran.nl/acat/files/42371410.jpg]Wing sail picture[/link]