Products
Blades
In autumn 2007 the first rotor blade ‘BARD 61’ left our manufacturing plant in Emden. It is designed for an optimum yield at high mean
wind speed. A relatively low turning speed and innovative production process ensure very long service life, and easy access for
repairs.
The ‘BARD 61’ blade is different from conventional blades, not least on account of its dimensions: length – 59.4 m, weight – approx. 28.5 t, and comparatively deep at the blade connection point, measuring almost 6 m.
Gigantic, but ideal, in terms of aerodynamics. Such a large rotor blade would be almost impossible to transport on land. But there are no limits for BARD aerodynamic engineers. We manufacture blades practically on the water edge and transport them directly from the production facilities. This means that we can fully concentrate on the efficiency of our rotor blades.
Our experienced design engineers rely on glass-fibre reinforced synthetic material based on epoxy resin, which efficiency has been proven for almost a quarter of a century in manufacturing of rotor blades for wind power plants. The lengthwise spar flanges are also of glass fibre. They guarantee rigidity. All three-dimensional components and bracings have a core of plastic foam.
Compared to wind turbines on the mainland, our rotors turn relatively slowly – at the same wind speed, around 20% slower. Normally the calculated ratio between the ‘speed’ of the blade tips and the wind speed, the so-called high-speed figure, is between 9 and 9.5. The special aerodynamics of the ‘BARD 61’ blade reduces this ratio between 7.5 and 8. Slow turning rotors reduce abrasion to the blade tips, and thus considerably reduce maintenance expenditure.
Many onshore wind energy converters stop generating electricity at
wind speeds which exceed 25 m/s. However, on the high seas the wind
regularly records this value, and often exceeds it. Our offshore blades
utilize wind speeds of 30 m/s, and therefore achieve much higher power
generation.
We also use an innovative process for rotor blade manufacturing. While the classical design is made of an upper and lower shell, ‘ BARD 61’ rotor blades consist of three parts: the central section with the root for the blade, as well as the leading edge and trailing edge. This facilitates handling during production, and avoids splicing at the sensitive sections of the leading edge and blade tip – which are wellknown trouble spots of conventional rotor blades.
| Technical data | |
|---|---|
| Blade length | 59.4 m |
| Max. blade depthe | 5.964 m |
| Pin diameter | 4 m |
| Depth at tip | 0.9 m |
| Total weight | approx. 28.5 t |
Manufacturing of the rotor blades