A Standing Problem

Scaling: a Weighty Issue

There is an age-old dilemma that plagues structural engineers and scale modeling enthusiasts alike: the problem of strength to weight ratios.  As a kid I wondering why a plastic scale model of an airplane was hopelessly unable to mimic, even on a smaller scale, the aerodynamic performance of the real aircraft.  Conversely, a toy or plastic model of a car can be dropped and make scale-speed impacts with similar vehicles without a dent.  Imagine a highway speed impact where vehicles bounce without damage!  Similarly, a model bridge glued from popsicle sticks could not be directly scaled up to a size capable of supporting actual road traffic with out significant changes in materials, dimensions, and joints.

Weight to strength ratios are often surprising.  For solid (non-hollow) structures, the weight to strength ratio of Balsa wood is greater than any metallic alloy (model rocket hobbyists take advantage of this), but its not possible to build an aircraft or rocket capable of carrying humans entirely from Balsa.  Looking at structures in animals, insects can carry proportionately massive loads on surprisingly thin legs and small lizards and frogs are able to climb window panes, supported only by the attraction force with glass.

Dino-Sized Concerns