A sewing machine has seam-forming tools, comprising a needle for guiding an upper thread and a looper. The needle is designed as a curved needle which is pivotable about a needle pivot axis. This embodiment is such that a distance of the curved needle from the pivot axis is equal to a radius of a curve of the curved needle about the pivot axis. The looper is designed as a looper which is rotatable about a looper rotational axis and has a lower thread reserve. The looper rotational axis runs parallel to a sewing material support region. The sewing machine can be used to produce a durable seam.

A spar for an airfoil comprises a core, e.g. a foam core, a central structural member extending through the core, an outer structural layer surrounding the core and central structural member and a plurality of yarns extending through the central structural member.

A spar for an airfoil comprises a core, e.g. a foam core, a central structural member extending through the core, an outer structural layer surrounding the core and central structural member and a plurality of yarns extending through the central structural member.

A hand sewing and knitting needle comprises an elongate body having a first end section extending from a first end to a middle section. The elongate body having a second end section beginning at the middle section and extending to the second end of the second end section. The middle section extending from a second end of the first end section to the first end of the second end section.

A hand sewing and knitting needle comprises an elongate body having a first end section extending from a first end to a middle section. The elongate body having a second end section beginning at the middle section and extending to the second end of the second end section. The middle section extending from a second end of the first end section to the first end of the second end section.