Cover of the folder "Theoretical study – hydropneumatic suspension 1943/44"

In this document

This page constitutes the handwritten cover of an archive folder. One can read, in red and vertically, the title of the file: "Étude Théorique ! Suspension interaction Hydro pneumatique 1943/44" p. 31.

In the top right corner appears a filing annotation in black pencil: "05-46" p. 31.

The medium is visibly a reused notebook: through transparency, the printed pattern of a notebook cover appears, with the word "Cahier" visible as a watermark p. 31. Some stains and a pencil line complete the page, without any particular informative value.

Context

The acronym DS and the hydropneumatic suspension are inseparable from the name of Paul Magès, a self-taught engineer who joined Citroën in August 1925 (autobiographical notes), who developed this system from the 1940s onwards — the plans for hydropneumatic suspension with differential interaction date from 17 February 1944 — before its industrial application on the Traction Avant and then, above all, on the DS presented on 6 October 1955.

The "hydraulic interaction", mentioned from the title of this folder, designates the principle by which the front and rear suspensions communicate with each other to improve the vehicle's attitude and comfort — one of Magès' great founding ideas, more than ten years prior to its production.

The mention "1943/44" places this research in the middle of the Occupation period, during which French automotive studies continued discreetly, often far from the halted production lines.

Archivist's perspective

This simple cover page has a value that is primarily organisational: it testifies to the creation, by Magès or his entourage, of a file dedicated specifically to the "theoretical study" of the hydropneumatic interaction suspension, as early as 1943-1944.

The annotation "05-46" (probably May 1946) suggests a subsequent filing or re-filing of the folder, at a date close to the first tests of the 2 CV with hydropneumatic suspension (May-July 1946) — which would explain the gap between the date of the content (1943/44) and that of the pencil inscription.

The reuse of an existing notebook as a cover medium is consistent with the context of material shortages at the time.

This document is part of a larger set of related items, notably the List of problems under study as of 22 February 1944 and the Plans for hydropneumatic suspension with differential interaction and automatic level control, which allow for a better understanding of the actual content of this "theoretical study" announced on the cover.