Windtunnel tests were done in the windtunnel of the Wolfson Unit in Southampton. A scale model of the Ecoliner was placed in the 4.6 m wide by 3.7 m high tunnel. Various sail configurations were tested including 3- and 4- mast configurations carrying 900 m2 and 1200 m2 sail area. Also the effect of reefing and the effect of deck cargo were investigated.
It can be concluded that a 4 mast rig does not provide a convincing aerodynamic advantage over a 3 mast rig and therefore 3 masts is the preferred option. The amount of sail area depends on the prevailing winds and the optimal amount is therefore dependent on the chosen operational area. Placement of deck cargo had a positive effect on the sail driving force since induced drag was reduced. Data for the reefed settings will be used in weather routing simulations.
The windtunnel tests are a vital part of the Ecoliner performance calculation. Therefore this is a big step forward in building the Ecoliner business case.