The invention relates to a rotatable cutting blade (100, 200, 300) including two blade arms (102, 104, 202, 204, 302, 304) which extend in opposite directions from a vertical rotational axis (X).The blade arms (102, 104, 202, 204, 302, 304) each have a front edge (114, 116, 214, 216, 314, 316).The each front edge (114, 116, 214, 216, 314, 316)include a cutting edge (118, 120, 218, 220, 318, 320), a back edge (122, 124, 222, 224, 322, 324) and a wing (126, 128, 226, 228, 326, 328) which extends from the front edge (114, 116, 214, 216, 314, 316)towards the back edge (122, 124, 222, 224, 322, 324). A streamline body (130, 132, 230, 232, 330, 332) is attached to each blade arm (102, 104, 202, 204, 302, 304) to distribute air flow around the blade arms (102, 104, 202, 204, 302, 304) during rotation of the cutting blade (100, 200, 300). The streamline body (130,132, 230, 232, 330, 332)is attached to the wing (126, 128, 226, 228, 326, 328)of each blade arm (102, 104, 202, 204, 302, 304)such that each streamline body (130, 132, 230, 232, 330, 332)extends behind the back edge (122, 124, 222, 224, 322, 324)of each blade arm (102, 104, 202, 204, 302, 304).Linvention porte sur une lame coupante rotative (100, 200, 300) comprenant deux bras de lame (102, 104, 202, 204, 302, 304) qui sétendent dans des directions opposées à partir dun axe de rotation vertical (X). Les bras de lame (102, 104, 202, 204, 302, 304) ont chacun un bord avant (114, 116, 214, 216, 314, 316). Chaque bord avant (114, 116, 214, 216, 314, 316) comprend un bord coupant (118, 120, 218, 220, 318, 320), un bord arrière (122, 124, 222, 224, 322, 324) et une aile (126, 128, 226, 228, 326, 328) qui sétend du bord avant (114, 116, 214, 216, 314, 316) au bord arrière (122, 124, 2222, 224, 322, 324). Un corps de forme aérodynamique (130, 132, 230, 232, 330, 332) est fixé à chaque bras de lame (102, 104, 202, 204,302, 304) pour distribuer lécoulement dair autour des bras de lame (102, 104, 202, 204,302, 304) pendant un
