"Aerodynamic scale effect" is crucial to both Thorp's and Bergey's reasonings, although Bergey does not mention it explicitly. He merely states that tapered wings tend to stall first at the tips. Thorp explains the reason in terms of Reynolds Number, a rather obscure but wonderfully useful index of the properties of fluid flows. The Reynolds Number, or RN, identified by the 19th century British scientist Sir Osborne Reynolds, combines the size of an object, the viscosity of the fluid in which it is moving and its speed into a single number, and states that fluid dynamics are the same at a given RN, however speed, size or viscosity may vary. Thus, air feels like motor oil to a gnat, and sea water feels like air to a whale?or something like that?and the flow around a small wing going very fast looks similar to that around a large wing going slowly. The thing about RN that matters to Thorp is that the lower the RN, the lower the maximum lift coefficient that a given airfoil can attain. In other words, a shorter chord means less lifting capability per square foot. It happens that this deleterious effect of scale is quite pronounced at the chord lengths and landing speeds typical of light airplanes, whereas it is less influential for airplanes with larger wings and higher landing speeds.