Frank Costin pioneered monocoque chassis design. He used his aeronautical knowledge to design and build a chassis from plywood. This led to a lightweight, stiff structure. Monocoque (French for single shell) or unibody is a construction technique that uses the external skin of an object to support some or most of the load on the structure. ... A chassis (plural: chassis) consists of a framework which supports an inanimate object, analogous to an animals skeleton; for example in the construction of an automobile or of a firearm. ... Aeronautics is the science and practice of aerial locomotion, i. ...