Square Top Rig

The RS Aero is easier to sail, faster upwind and more stable downwind than the Laser.  It is not just the Aero's hull shape and light weight, the modern rig is simply superior.

The RS Aero has a distinctive squatter sail shape and compared to Laser's tall pin head rig, or roached sail.

Comparing the two types of sails, the theory goes:

· For the same surface area, a square head sail will have a smaller mast than a roached sail, therefore the centre of gravity of the rigging, and the centre of effort of the sail will be lower, which increases the lateral stability of the boat,

· The square head will allow a better control of the main sail twist, and self-regulates the sail shape during gusts,

· The head of a square head sail will be more tolerant for small angles of attack, and produce less induced drag,

· The square head will give a better aerodynamic efficiency in the upper part where the wind is stronger, the square head does not increase the lift but reduces the drag.

When the two rigs are placed one over the other it is clear 
the the Aero square top rig has a shorter mast and relatively more sail higher up.  The Aero 7 rig 7.3m2 is comparable to the Laser Standard with 7.1m2.

With the masts placed together at their base, the Aero mast is 50 cm shorter and the Laser goose neck is 10 cm higher than the Aero. 

The carbon top section is considerably thinner and lighter than the Laser's so there is much less weight in the sky.

(Thanks to the Tillerman's propercourse blog and the MSc thesis of Damien Lafforgue)


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