It should be something like…
1º: Draw the shape of one blade as if viewed from the front.
2º: Create a null layer and position it on your desired anchor of rotation. (botton center, in that case)
3º: Set both layers to 3d. (null and shape)
4º: Link the blade(shape) to the null layer.
5º: Either rotate them to the desired position or create a camera and position the camera.
6º: Duplicate the shape 3 times and unparent these three.
7º: Rotate the null 90º in X, relink one shape, repeat 7º for the remaining two shapes.
Cassius Marques
http://www.zapfilmes.com