Speculations on the mechanics of airships of Santos=Dumont - Propeller Shaft and Rudder
Autor: Luiz Pagano | Publicado: 2014-11-03T15:13:00-08:00



In this photo we see the stern of No. 6


The researchers of
Santos = Dumont knows well the episode of Bénerville
(http://santosdumontlife.blogspot.com.br/2011/06/santosdumont-erases-part-of-his-history.html)
in which Santos=Dumont set fire in all his projects, leaving us only with our
assumptions, some texts and photos to fathom the workings of his inventions.

leia este artigo em Português



The only way to
reconstruct his mechanics are doing a composition of texts written by him, with
a deep analysis of old photos and then to extrapolate the remainder from pure
logic.



One of the adaptations
that raises more questions is how the bottom part of the helm of dirigibles No.
6 and No. 9, appear to be connected directly to the propeller shaft. We see old
photos and we get scared when realizing that the rudder cables seem to come
straight from the spinning axis of the helices, which, of course would be
impossible.

&nbsp;

Here the stern has its parts was transferred to a software, so that we can study each function separately.



Once you have eliminated
the impossible, like the character of Arthur Conan Doyle, Sherlock Holmes does,
we set out to the unlikely however plausible alternatives. In the case of
Santos=Dumont, the word 'unlikely' should be replaced to 'elegant solutions'.



That said, we reached
the conclusion that the only way for the rudder cables not curl all around the
propeller shaft would be that the dirigibles mentioned, would use something
equivalent to a "tube-in-tube 'system. A tubular external shaft that
supports the helix, would rotate freely around a internal and thin shaft, firmly
connected to the nacelle.

&nbsp;

In this photo we isolated even more the important parts, in order to know how the inner shaft, fixed to the nacelle, holds the rudder cables.


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Once formulated this
theory, I pick up a photo of the back of a dirigible, I designed structures
over the photo and extrapolated the 'tube-in-tube' system. The result was
astonishing. 




In this diagram, we understand even better how the 'tube-in-tube' system works, the outer shaft has at its tip a large cogwheel that spins around the inner shaft, fixed to the nacelle, triggered by the small cogwheel, whose axis comes directly from the engine.