There goes my theory about high aspect efficiency. Paulo Dos Reis leading Antoine Albeau.
That's been in my head recently, as a person with ducks disease, and a light weight to boot, I find normal aspect ratio sails, have to much power high up. I've had a feeling that I would be able to hang on to a more powerful sail if the power was lower down. Sacrifice a bit of sail efficiency for a bit more power.
if you are talking speed sailing off the wind then high aspect is still faster as i understand it.
but upwind lower aspect has the edge and in my mind always has. i myself prefer lower aspect sails because i like to sail upwind and enjoy the improved acceleration they provide, i was never really a convert to the whole high aspect thing. but then i'm not a speed sailor.
there has been some interesting discussions on the KA forums about the comparison between the KA Koncept and the KA Race which makes good reading. to take one comment out of the discussion the KA Race (lower aspect) performed better upwind.
edit* the thing i find amazing about that north sail is the size of the head!!! how much drag must it create?
on a side note, there is an interesting discussion on the starboard forums about AA at the formula worlds and about his sails, boards and fins.
and of course he won the comp.
Chris Lockwood was on to this years ago but had trouble getting it put into practice for a couple of reasons. Severne built him a couple of Low AR sails but they didn't work out for a number of reasons and it wasn't helped by the canal at St Marie del la Mer in France having a metre high windward bank which suited Finian's high AR Naish sails and left Chris in disturbed air with his low AR Severnes. Additionally Dan Engdahl was also on Severnes pushing for the oppposite in his protos on the basis of better aerodynamic efficiency.
Of course all aerodynamic theory is based on planes which have another wing on the othe side of the fuselage to balance the lift forces. Maybe if the passengers had to hold the wings on we would be flying around in planes with low AR wings
The new Pryde protos have much shorter luffs. I think Chris had a 400 in his 6.2 when he did 45Kn at Pt Walter. The North is a bit different as it has a huge head..it looks like they just chopped the top pannel off.
As Bugs is about to design me 3 new sails, I forwarded this post on to him for his comments.
Here they are
it's a guess on my part but i don't know how user friendly a low AR sail with a deep forward draft would be and especially for lightweights. there would be, i would have thought, way too much power to deal with as the area of draft would be huge.
maybe we are about to see the return of smaller sail sizes in typical winds?
certainly most of the lightweights i know don't feel comfortable on long boom sails. the majority say the sails too powerfull.
