Moth wingbar position

[phobos132]

Hey,

been lurking here for a while, first post.

I'm hoping some of the guys who've actually sailed moths can help me out with a question: Do you ever end up sitting towards the stern on the wingbar? I may have just not been paying attention, but it seems that the sitting position varies between the middle of the bar and the front. Do you only end up further back going downwind in really high winds? Or do the foils do such a good job of keeping the boat level in pitch that it doesn't really matter where you sit?

Mach 2s have the fronts of the wings rounded (I assume to reduce windage), why not do the same with the back, or make the wings smaller altogether? Or is the large wing just there to make sure you don't slip and fall off the back of the boat?

Cheers.

 

[Phil S]

In the 10 years of foiling the rear wing has migrated forward up to half a meter. The only time you even sit that far aft is when some component of the foil system is broken and the lack of flap control means the bow will not come up. The foils normally control pitch stability very well so long as they remain in the water.

 

[pkilkenny]

In the 10 years of foiling the rear wing has migrated forward up to half a meter. The only time you even sit that far aft is when some component of the foil system is broken and the lack of flap control means the bow will not come up. The foils normally control pitch stability very well so long as they remain in the water.

An alternative comment from one of the faster US Moth guys (big wind specific):

http://foilertownusa.blogspot.com/2010/11/wild-horses.html

 

[phobos132]

Thanks for the quick replies guys!

Do you see the wings getting smaller still or has their size stabilized now that the foilers have been around for a little while?

 

[the_skiff_devil]

I don't see wings getting too much smaller... however I do see them becoming increasingly more aerodynamically important. With the rig drag being ditched by way of wings and the latest hulls are pretty much on the practical limits (although if control systems keep getting better, hulls in the traditional sense will become increasingly redundant) the only real spots to keep pulling drag out are the hiking appendages and foils to a lesser extent.

I think the smallest wings I've seen so far are on Nick Flutter's rebuilt boat; his back wingbars look like they're about 650mm from the transom, and his front bars are angled back like Doug Culnane's flasheart (think mach2 front bar style but instead of rounding the corner, it's just cut straight back at an angle).

 

[leighhutchins]

On wing bars...what is the normal tube size and wall thickness being used to make a stiff platform these days.

Leigh

 

[rtrs]

i could be wrong but looks like the back wingbar on the assassins is farther forward than other moths

 

[GSJ]

In the 10 years of foiling the rear wing has migrated forward up to half a meter. The only time you even sit that far aft is when some component of the foil system is broken and the lack of flap control means the bow will not come up. The foils normally control pitch stability very well so long as they remain in the water.

There are some different opinions about where to be seated especially in heavy air when people are really hauling. I am only a beginner moth sailor who has not down much more than 25knots of boat speed but my boat seems to like it better when i sit about half way along the wing when bearing off in heavy air.

 

[mark1234]

Check out Mike Cooke's Ninja's (Aardvark boats) - you'll find a few interesting things; a very reduced wing length fore-aft (sweep back on the front bar and forward on the rear). Also a fixed rudder (no pitch trim). Seems to work OK.

On my prowler I sometimes sit right in the back corner with rudder lift wound on - there's a school of thought suggesting that's good for out of control downwind sailing. I'm not fully convinced personally.

 

[flutter]

the front wingbar is located by the shroud attachments- a point that is related to the mast step position.

the back wingbar can move wherever you want. I feel that it can be 600mm forward of the transom as there is really no need to go back there (in my expereince) The curve on the assassin/br/mach2 is there because you dont need wings at the sidestay, and its probably the stiffest way of joining the front wingbar truss at the chainplate with the outer bar. and i think the big corner like the prowlers have looks ugly. My current thinking is that you dont need big wings at all. mine are quite small but i think they could be a lot smaller. so say from 600mm from the transom, forward 800mm and thats it. that would be an adequate size platform for less windage than we see at the moment.

now if we could just get rid of the sidestays once and for all, you could make the wings as small as you want.

nick

re: downwind - pull your wand shorter and pull your ride height up, and wind lift on the rudder.

i think...

 

[sinktheboat]

I wouldn't make them any shorter than the assassin! Now we are running less AOA you need to get to back of our wing frame at times.

On the e2 we ditched the nice sexy corners on fnt bars so we can buy HM bars off the shelf anywhere in the world, and the boat sits on it's side without falling on bow all the time.