​Sirius Sails

 Model Yacht Sails

For additional information contact:  ​don@siriussails.com  or (561) 676-7639

Q. Ways to contact Sirius Sails?

 

A. Email at don@siriussails.com or phone (561) 676-7639


Q. Why the Distributed Camber trade mark?

 

A. Most sail block made sails have the max. camber located in the same place from the top of the sail to the bottom of the sail.   Typically 40% of the chord.   No full sized racing sails are designed or made this way.  Sirius Sails, like full sized racing sails, have the max. camber locations positioned to achieve elliptical loading of the entire sail plan.   Each quarter point has it's own camber location.  This design approach inherently reduces form drag.   Also, the main’s camber locations are further positioned to maximize the main's upwash effect on the jib.   The trade mark is used to differentiate Sirius Sails from all other model yacht sails.

 

Q. Why are “circular arc” shapes bad?


A. Up until now, sail blocks, which produce various circular arc shapes, were the only practical way to produce cambered seams for small model yacht sails.   Even the largest models have very small sails compared to any full sized yacht, making seaming and shaping problematic.  Circular arc shapes are not ”bad,” they are just much less than optimal for racing sails, primarily because arcs are a very high drag shape.   Model yacht sailmakers try to mitigate and improve the shape of block made sails by using stiff battens to help flatten the leech area and reduce some of the drag.   Also, relatively high luff tensions and in some cases mast prebend, are required to “pull” some of the arc shape more forward to improve the entry angle and to also help flatten the leech.  Setting more twist in block made sails is also used by expert sail trimmers to further mitigate the arc shape.


Q. How are Sirius Sails designed differently than block made sails?


A. Sailmakers of block made sails are focused primarily on making cambered seams and finishing the sail.  Performance is the result of trial and error .   They are not “designed” in the engineering sense and much of the final sail shape is a result of default and the expertise of the sail trimmer.   Sirius Sails design considers all aspects that effect the shape of the sail, the same way that full size sailmakers do, but on a much smaller scale.   Specific custom 3D sail software is used to design the amount of camber, it’s distributed location, vertical shape partitioning, entry angles, exit angles, twist and all the offsets that are all built in and create the final shape of the sail.   All design parameters are determined by considering the sail plan and sail material, hull, displacement and ballast characteristics of each class of model yacht.


Q. How does your seaming tool work differentlly than a sail block?


A. To make sail block seams, the cut panels are aligned and draped across the sail block and then taped together.   Bridging the ridge on the sail block, or sail board, results in a seam that creates a circular arc.  The final output of the Sirius Sail software is the X/Y coordinates of each seam, much like a pattern.   The custom seam tool is set for those coordinates and holds the panels in place until they are taped together.   Settings are repeatable to within .05 mm.


The result is a broad seam identical to those used by full sized sailmakers to produce true airfoil shapes, except on a very small scale.


Q. What do you recommend for sail material?


A. Most model yacht sailing is done in wind speeds well under 10 mph.  I like to recommend combining a lighter jib material with a heavier main material.  Typically TS25 for the jib and TS40 for the main.  Doing this provides a reasonable compromise between racing life and ease of reading the sails and their responsiveness in light air.   Jib loading is far less than main loading in all conditions and in almost all yacht classes.  Therefore, occasional heavy air sailing can be tolerated without damage to the sails.  


Sirius Sails FAQ's