Abstract: A flywheel-type power storage device comprises a coreless synchronous and outer rotor-type motor and a flywheel. The motor comprises a stator provided with a stator winding having a cylindrical portion, and a rotor having inner and outer field members constituting therebetween a field gap in which the cylindrical portion is positioned. At least one of the inner and outer field members comprises a permanent magnet. A bearing is provided between the stator and the rotor so as to rotatably support the rotor against said stator. The stator is separated into a bearing portion constituting the bearing and a stator body provided with the stator winding. The bearing portion is supported via an elastic member by the stator body. The flywheel is fixed on the outer side of the outer field member.

Abstract: A fiber-reinforced composite cylindrical form formed by winding up unidirectional prepreg sheets around a mandrel according to such four patterns as to set the fiber winding angles of the resulting layers thereof at 0.degree., 90.degree., 40.degree. to 50.degree., and -40.degree. to -50.degree. with the longer direction thereof, and then heat-curing said layers of said prepreg sheets.

Abstract: A spirally woven fabric as well as a prepreg and a rotary body each using the fabric therein is adapted for use as materials for high-speed rotary bodies such as flywheels for electric power storage. The fabric composed of interwoven warps and wefts is such that its warps are arranged in a spiral direction, and the warps positioned more outside in the radial (weft) direction have a higher specific elastic modulus in the warp direction than those positioned more inside in the radial direction whereby a rotary body made of the fabric is enabled to be rotated at a higher rotating speed without breakage of the wefts and consequent peeling-off between the warps.

Abstract: A fiber-reinforced composite material is disclosed for use as a cable which comprises a master filament and a plurality of slave filaments disposed in surrounding relation thereto, both filaments being impregnated with a resin and thereafter coated by a knitted fiber web. The filaments are formed of a fibrous material of a selected class and have their respective tensile strength, elongation and moduli specified to achieve a desired cable quality.