The prototype is being assembled near Roskilde, eastern Denmark, this week.
Windpower Monthly's technical expert Eize de Vries visited the factory in Nakskov, southern Denmark, and discussed the potential of the concept with Vestas engineers.
The turbine incorporates four refurbished pitch-controlled V29-225kW turbines with unchanged 29-metre rotor diameter.
It features two nacelle operational levels with a cylindrical tower section in between and 30.5-metre height interspacing between the levels. The structure's tip height reaches 74 metres.
The nacelles are mounted separately on left and right side tubular-steel arms. These arms in turn are flexibly attached to a turnable central chassis.