Speculations on the mechanics of airships of Santos=Dumont - Propeller Shaft and Rudder

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.

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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.

 

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.

 

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.

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.