Having both a Kyosho Fortune 612 (Oracle) and a 2.4mr (minitwelve) it is obvious that the sails to large extent are in the medium transition zone between water and air. Many textbooks on sailing wheather show the zero wind speed at water level, and “exponentially” increasing with distance over water. Other parameters like water- and airtemperatur naturally can influnce (termic and so on). In the case of a 2.4mr racing jib the influence of the transition zone on its design is obvious: a big depth in its upper part and a comparatively flat lower section. In case of rc we can of course sail in flat water which makes the sail design less sensitive. But there still is a medium transtion zone strongly influencing our doings.
Regards,
Booster
Just a question concerning your oracle!
A friend of mine just got an Oracle, and I had to reshape the sails? how about you, did you do other “improvements” as well?
Hi!
In the case of the 2.4mr the intersection of the fore-stay with the mast is comparatively low. While the boom is attach rather “high” on the mast (head injury reasons). So there is a rather small region of the sails effectively overlapping. Thus, the full depth in the upper parts of the jib is more or less “save whatever can be saved”. One even has to use half-width panels in the jib in order to squeeze as much depth as possible into the sail without getting wrinkles. The sail-cloth fabric of the Orcle should be as soft as you poosibly can, in case of the main (consider wear and fatige). Thus, allowing reshaping. The jib is not so sensitive in this respect. The possibility to use a large number of sail-cloth panels is strongly limited by manufacurer tolerances in case of rc. Fractions of mm shall results in sail depth, and how easy is that?
Regards,
Booster
Booster you are wrong about the 2.4mr, it isn’t a mini 12, the illusion is the only true mini 12, Does the 2.4mr have kite? NO, does the 2.4mr have a proper Genoa? NO, does the 2.4mr have a keel that looks like the 12’s keel? NO. The 2.4mr is designed for disabled sailors. Only the illusion is designed to be a true mini 12.
Regards,
Rob
You are correct. I forgot to answer your previous question regarding this. Both spinnaker and genua was tested several years ago on the mini-twelwes. But the boat handeling became hazardous. So one agreed for a 110% overlapping jib, and skipped the spinnaker. Moreover, the stability was increased by putting more lead into the keel-pocket, and the name was changed to 2.4mr. Recently we have a 95% jib as an alternative to the 110%. In the 95% jib battens are allowed and a “convex” trailing edge. In the last Word championship the winner, Marko Dahlberg (Finland), had a 95% jib. That jib was originally designed to allow disabled sailors to jibe more easily using a jib-boom. The both jib-designs seems to result in rather the same speed. Proving the 2.4mr to be a well-integrated class between non-disabled and disbled sailors…
Regards,
Booster