I was wondering what peoples thoughts were on the leech shape of the sail. AUS 230's mini with the Airtrack sail has a negative leech. Some have a straight leech and some have a positive leech/roach.
John,
Just unsubstantiated opinion, but I'd favor positive roach on big light air sails, to grab as much power from up high as possible. And as the sails get smaller for heavier air, go to less roach, partially because it'll be hard to keep the leech from blowing off and creating drag, and partially to lower the center of effort, which will be welcome on a mini. I could see a negative cut leech on sails under 3.5 to 4 meters.
Dave
Be mindful that most Mini land yacht sails are in fact recycled sails which were designed for other sailing sports, Very few land yacht sails have been started with a clean slate and those that have have been designed for a specific location or problem.
If you do some research on sail design you will keep coming up with this guy... Czeslaw Antony Marchaj some of his ideas are worth considering. His books are not cheap but are full of information.
en.wikipedia.org/wiki/Czes%C5%82aw_Marchaj
A lot of the current sail profiles would be less than ideal for high speed sailing according to the info and data out there.
The trend in Europe at least with new sails whether it be class 2 3 or 5 seems to be a moderate flat head with a straight leach. I do agree with Dave that with a positive roach and the proper batten and leech tension that is a better set up for light to moderate winds. I would guess it's important to get tension on the second batten down from the top to set the stage for the rest of the sail. I'm a little curious as to a high wind sail set up. Is it better to eliminate the fathead or not. If made right it can twist off in the puffs keeping the boat happy. Is this (twist) causing more drag on the sail plane? What is best a happy boat or a draggy boat?
My thoughts are to eventually have 2 sails for the mini. One about 3.5m and one about 4.5 m. Both would have the same luff length. The larger will have about 4'' of roach and about a 22'' head . The smaller will have to be raked more and have the back of the sail cut off straight as much as needed to make it a 3.5 m.
A lot over here and main land Europe are using class 5 rigs at 5m. There are quite a few 6.5m mini rigs out there, and one company in Europe (think it was Sweden) is selling an 8m light wind sail for their mini (a jaw dropping moment when I saw it on their list mind).
A lot over here and main land Europe are using class 5 rigs at 5m. There are quite a few 6.5m mini rigs out there, and one company in Europe (think it was Sweden) is selling an 8m light wind sail for their mini (a jaw dropping moment when I saw it on their list mind).
We're using the 5.5m on a 2 mile long concrete runway on Seagull Silence style mini yachts and on x-sails. get.google.com/albumarchive/pwa/118219853851556300124/WorldChampionshipsCherrueixFrance the first third of this album is the minis racing at the Worlds in Cherruiex, France. There's quite a few Class 5 set ups there (including the current world champion). It was like the wacky races out there, brilliantly entertaining racing.
Cheers Col
What wind ranges are you using the 5.5? I spoke with some of mu friends from the US that raced mini in France. They said it was a blast. The flying start would be interesting if the wind was in the 20's
The more experienced are using the 5.5m sails in the same winds as the class 5 pilots, this may be because the Silence weight is held very low. I wonder whether the flexible rear axle helps with this as well. As i can use the clubs Seagull MC2 in higher wind speeds than the people with x-sails/blokarts with the 4.5m sail as gusts are soaked up by axle flex.
The US will love the mini yacht. Don't need a trailer, or big storage space, and hopefully big grids for close and crazy racing
Cheers Col
for your US surfaces 4.5should be fine unless you have selfballasting tendencies 
, maybe 5m for a light wind.
keep in mind that the european sails cut specifically for a mini tend to be fuller with much lighter battens,on a lighter mast than you would use on a class 5.
my australian sails were just too flat for cherreiux. they were ripping fast upwind ,but next to useless on the narrow restricted downwind leg of the course.
i repowered my mini with my class 5 sail AND mast ,which gave me the sail area and hieght to get back into a top ten position but with the stiffer class 5 mast I was constantly on 2 wheels upwind,and slower than when i was using my 4.5
it really is a case of horses for courses
