A rotor blade having a chord and a span length perpendicular to the chord, the rotor blade comprising: a leading edge, a trailing edge, a first skin having an inner surface and a first plurality of elements extending from the inner surface at least a portion of the distance between the leading edge and the trailing edge of the rotor blade, each of the first plurality of elements comprising a tongue, the first plurality of elements being distributed along at least a portion of the span length and inclined with respect to the chord of the rotor blade by an angle greater than 0°; a second skin attached to the first skin so as to form an outer surface of the rotor blade the second skin having a second plurality of elements extending at least a portion of the distance having a second pluratity of elements extending at teast a portion of the distance between the leading edge and the trailing edge, each of the second plurality of elements comprising a groove, the second plurality of elements extending towards the inner surface of the first skin and engaging with the first plurality of elements when the second skin is attached to the first skin, the first plurality of elements and the second plurality of elements forming a plurality of ribs within the rotor blade, wherein each of the tongues of the first plurality of elements are configured to interlock respectively with each of the grooves of the second plurality of elements to form the plurality of ribs; and a first plurality of spar elements which extend from the inner surface of the first skin, and a second plurality of spar elements which extend from the inner surface of the second skin, wherein the first plurality of spar elements comprise tongues and the second plurality of spar elements comprise grooves, and the first and second plurality of spar elements are joined by mating the tongues with the grooves to form a plurality of spars extending along at least a portion of the spar length of the rotor blade. a leading edge, a trailing edge, a first skin having an inner surface and a first plurality of elements extending from the inner surface at least a portion of the distance between the leading edge and the trailing edge of the rotor blade, each of the first plurality of elements comprising a tongue, the first plurality of elements being distributed along at least a portion of the span length and inclined with respect to the chord of the rotor blade by an angle greater than 0°; a second skin attached to the first skin so as to form an outer surface of the rotor blade the second skin having a second plurality of elements extending at least a portion of the distance having a second pluratity of elements extending at teast a portion of the distance between the leading edge and the trailing edge, each of the second plurality of elements comprising a groove, the second plurality of elements extending towards the inner surface of the first skin and engaging with the first plurality of elements when the second skin is attached to the first skin, the first plurality of elements and the second plurality of elements forming a plurality of ribs within the rotor blade, wherein each of the tongues of the first plurality of elements are configured to interlock respectively with each of the grooves of the second plurality of elements to form the plurality of ribs; and a first plurality of spar elements which extend from the inner surface of the first skin, and a second plurality of spar elements which extend from the inner surface of the second skin, wherein the first plurality of spar elements comprise tongues and the second plurality of spar elements comprise grooves, and the first and second plurality of spar elements are joined by mating the tongues with the grooves to form a plurality of spars extending along at least a portion of the spar length of the rotor blade.