Patent attributes
A method of fabricating a double-walled shell of fiber reinforced plastic material is by centrifuging. The outer wall of the shell is made by projecting glass fibers and resin in a liquid phase against an inside face of a cylindrical mold rotating about its horizontal axis. A section member is then applied against the inside face of the outer wall by a plurality of turns having a diameter substantially equal to the inside diameter of the outer wall and separated from one another by a distance substantially equal to the thickness of the outer wall. The section member has a channel section with a web and two flanges extending radially outward, defining a sealed helical duct. The space between the turns is filled with resin by centrifuging, forming a helical spacer, and the inner wall is formed by centrifuging.
