Hydraulic suspension test report of 19 May 1949 at La Ferté

In this document

This typewritten sheet is a test report for hydraulic suspension carried out on 19 May 1949, on the La Ferté circuit p. 78. It bears the handwritten date "19.5.49" in the header p. 78.

Participants

The people present or associated with the test are listed by name: Messrs. Boulanger, Cadiou, Duclos, Lefebvre, Magès p. 78. We therefore find Pierre Boulanger, then head of Citroën, alongside Paul Magès.

Two compared settings

The document compares two suspension "settings", designated by letters:

p. 78

The report concludes that setting J constitutes the "best compromise so far" and deems it "good for Clermont tests" p. 78.

Context

At the date of this test (May 1949), Citroën had been developing the principle of hydropneumatic suspension for several years, under the impetus of Paul Magès — whose first plans date from 17 February 1944 (Hydropneumatic suspension plans with differential interaction (17 February 1944)) and the first tests on 2 CV from May-July 1946 (Notebook of the first 2 CV hydropneumatic suspension tests (May-July 1946)) — which would later equip the Traction 15-Six H, tested on 3-5 April 1954 (Road test of the 15 Six H (ELV 412) by Paul Magès, 3-5 April 1954), then the DS presented on 6 October 1955. This May 1949 report is therefore part of this long development phase, between the initial plans of 1944 and the successful tests on the 15-Six in 1954. Pierre Boulanger, Director General of Citroën until his accidental death on 22 September 1999, personally followed these developments. The La Ferté-Vidame circuit was the brand's private test track. These general context elements do not appear in the document itself, which remains a raw technical report.

Archivist's perspective

This document concretely illustrates the empirical development method used by Magès' team: comparative tests of settings, designated by simple letters, judged on qualitative criteria (road holding, shock behavior) rather than precise numerical measurements, apart from the setting parameter itself p. 78.

The mention of upcoming tests "at Clermont" suggests an itinerant test program, probably intended to validate the settings on roads different from those of La Ferté p. 78. The joint presence of Boulanger and Magès in the list of participants p. 78 testifies to the direct involvement of management in these tests, consistent with the strategic importance given to this project at Citroën at that time.

This sheet probably finds its place in a larger set of similar test reports; it can be usefully compared to the Summary of folder 41-59, which lists the various documents relating to hydropneumatic suspension, as well as the Folder "Theoretical study – hydropneumatic suspension 1943/44", which documents the earlier stages of this same development.