Fan rotor blade with flap, has flap section with cross section defining two different angle geometry regions

摘要

Flap section has a constant cross-section and comprises a first region next to one end of the bearing surface section and a second region between the first region and the other end of the bearing surface section. The angle between the cross-section of the flap section and the bearing surface section is always the same in the first region, but decreases towards the other end in the second region. A rotor blade (40) for a fan or ventilator comprises an elongated, essentially wing-shaped bearing surface section (41) with a means at one end for securing it to a hub. The bearing surface section has a flow direction extending essentially perpendicular to its length direction and a flap section (42, 43) is provided behind it, with respect to this flow direction. The flap section has an essentially constant cross-section in the length direction and comprises a first region next to one end of the bearing surface section and a second region between the first region and the other end of the bearing surface section. In the first region the angle between the first region cross-section and the bearing surface section is essentially always the same, whilst in the second region the angle between the second region cross-section and the bearing surface section decreases from the first region to the other end of the bearing surface section. An Independent claim is also included for a method of making the rotor blade by extruding a profile with a wing-shaped cross-section comprising flap and bearing surface sections and then bending a region of the flap section.