The Ereminas chassis stiffener

[JHertzman@domain.elided]

The Ereminas chassis stiffener is an interesting and improbable device indeed 
unless one considers it purely as a pair of compression struts linking the 
front frame to the rear frame. If a rectangular structure with several 
parallels in a single plane is twisted it becomes an hyperbolic paraboloid; 
if the two ends merely twist but do not bend, the parallels within the plane 
must shorten. If they cannot shorten, the ends must bend. To the extent that 
the ends resist bending and the parallels resist compression, the plane 
resists twisting. The floor-pan within the rectangle could contribute a great 
deal if it were flat, but its several corrugations make it as limp, for 
torsional resistance, as an accordion. I would guess that the person who 
designed the Ereminas chassis stiffener may have started by trying to 
understand what the two short tacked-on tubes contributed to the Milano's 
understructure; once he had had his Eureka! moment, that they were purely 
compression struts bridging accordion folds in the floor-pan, the extension 
of the idea to the Spider would have been a natural step.

Or so it seems to me - -

John H.

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