Spars
We are now offering three different designs in aluminum spars for several different classes. All of these spars are our own designs extruded from our own dies and kept in stock ready for shipping. All of our spars use a sailtrack in the mast to accept a bolt-rope luff Mainsail, just as you would find on a full sized yacht.
The three designs are:
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The standard airfoil shape
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Oval shape that is larger and stronger for the largest models
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A round spar made specifically for the IOM class.
The airfoil shaped spar was made for the medium sized boats such as the EC-12, Santa Barbara, Soling 50, 6 Meter and many other midsized model boats. This is a light weight high strength 6063 T-6 aluminum extrusion that comes in a clear or black anodized finish in lengths up to 72" The mast is semi-scale in appearance and functions exactly the same as the mast on a full sized sailboat in that it provides for a smoother entrance of the relative wind to flow across the sail and give your boat the power it needs.
The Second design is more oval shaped and was intended for the J Class, and AC Class and is available in stock lengths of 10'. If you need lengths in excess of 10' this spar may be spliced up to 12', beyond that length has not been tested, but possible.
The Third design, and our newest is a round spar with the sailtrack included. This mast is exclusively for the IOM class since it requires a round mast by rule.
Airfoil Aluminum vs. Round Carbon
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Why you want a bolt-rope mainsail
Do not be fooled into thinking that you may gain an advantage by using a round carbon mast in lieu of an aluminum spar. Check the weights on them both and you will find the difference, if any (and if it's in favor of the carbon... it may not be) is so slight as to be only measured in grams (if you have access to a scientific scale that is accurate to 1 gm) Where you will find the difference, is in the airflow as it enters your mainsail.
There are many reasons why an airfoil shaped mast is superior to a round mast, not the least of which is the fact that there is no more un-aerodynamic shape than round. The proof being that were it faster, you would see it on full sized boats. Secondly, round masts require you to attach the mainsail in such a manner as to provide an inferior and turbulent entry of the airflow onto your mainsail. A smoother entry means a higher AoA is obtainable (Angle of Attack) which translates into your boat pointing higher. Furthermore, the sooner the airflow smoothes out onto the sail surface the sooner it begins producing lift, hence the sail is more efficient. The importance of the sailtrack and boltrope main must not be underestimated. The fact proving this is the existence of the IOM masts which are round by class rule, but have been made with a sailtrack to gain every possible advantage in this critical area.
There is an old wives tale about bolt-rope mainsails, that the "S" curve caused by tendency of the sail to not want to fold over causes you to lose sail area and performance downwind.
These are models that accelerate to hull speed within their own length.
You must realize that before anything else in racing models will come into focus. ANY advantage gained by using a "hinged" mainsail (i.e. one that uses cutouts in the luff of mainsail and either jackline or slugs mounted to the mast) or even worse.. sailrings... is limited only to that initial 1 boat length required for the model to achieve hull speed, after which all boats are even. Also, this only applies to the DDW (dead down wind) leg. If you are sailing a reach, then the sail is never taxed to a 90 degree position.
Then too, most race courses feature one more upwind leg than downwind leg, so if you were to chose where your performance would need to be the best, numerically it would be on the windward legs, and lastly... I was always taught that upwind performance was the most critical, and where the races were usually decided. It is for all these reasons that I recommend an airfoil shaped mast with a sailtrack and bolt-rope main to maximize your boats pointing ability and performance to the weather mark.
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