Why an external RAT on this early propeller plane at Charlotte? At the Charlotte airport, I caught a glimpse of the Bellanca 14-9L with State Airlines livery they have on display. They call the Bellanca the first plane with retractable landing gear but that's not what struck my attention:



There is a ram air turbine generator visible  and permanently located between the landing gear (circled). I only know of RATs as providing emergency power for airliners -- and they are only deployed (pushed outside) when they are needed. The other use for them is apparently on cropdusters.

Why did this airplane need a RAT permanently installed? Wouldn't it be much more power efficient and aerodynamic to provide DC/AC power through a magneto or alternator on the engine? 

Late note: I looked at pictures of other Bellanca 14-9L and they don't show a RAT. Perhaps this means that this plane was not a passenger craft (as its "State Airlines" livery indicates) but was in real life a cropduster?

(Photo by author. Released cc by-sa)
Many older aircraft could be equipped with an optional external air driven generator, including, for example, the Luscombe 8A. Some air driven generator models were granted a Supplemental Type Certificate (STC) allowing them to be added to specific aircraft, such as the venerable J-3 Cub. The reason these were used is that, as you surmise, the engine is not equipped with any mechanism to drive an alternator or generator, i.e., there is no pulley, no gear mechanism, etc. Examples of those engines, still in use today, are the A-65, A-75 and original C-85. Newer designs of air driven generators are still available today, such as the BPE14 TURBO STAND-BY ALTERNATOR. The disadvantages include increased drag and exposure to ground obstacles, debris and of course, birds and bugs!