Handwritten note from 1967: organisation of road tests and vibration research

In this document

This handwritten page dated "1967" p. 99 organises, in the form of a diagram with braces and arrows, the distribution of tests and research between several participants and two material centres: the "Labo P" and the "BEA".

Road tests – Suspension

This concerns the "fine-tuning of the suspension in general" and the "rapid detection of parasitic frequencies affecting comfort", using the equipment of Labo P. Two names are associated with this task: Mr. de Lassus (mention partially crossed out, illegible) and Mr. Hondet p. 99.

Vibrations and noise

A second branch of the diagram entrusts Mr. de Lassus, with the equipment of the BEA, with the general study of "vibrations" and "noise" p. 99.

Stationary tests

The document distinguishes between two campaigns conducted "at a stationary point":

• the "search for uncomfortable parasitic frequencies", entrusted to Mr. de Lassus with the BEA equipment;
• the "search for high frequencies", also attributed to Mr. de Lassus with the BEA equipment p. 99.

An arrow connects Mr. Hondet to a "measurement programme" transmitted to Labo P, which is itself connected to a "Calculation" station p. 99.

Equipment summary

The page ends with a summary: road measurements mobilise "Labo P personnel and equipment", while the detection of vibrations "and the search for their origin, and the study of solutions" rely on Mr. de Lassus and the "BEA apparatus". Several words are crossed out in this passage, notably "research" and an illegible segment, which makes certain nuances uncertain p. 99.

Context

The Labo P and the BEA (Automotive Design Office) designated, at Citroën, distinct departments: the former more focused on physical tests and measurements, the latter on engineering and design. In 1967, the DS was at the end of its commercial career but continued to benefit from improvements, while preparatory studies for the future CX were progressing — the acoustic and vibratory comfort of hydropneumatic suspensions remaining a central subject for the brand, known for its lead in this field.

Archivist's perspective

This note does not bear Paul Magès's signature, but it likely comes from his workshop, as it testifies to a methodical organisation of research into comfort — a constant theme of his work, already present in earlier notes such as the one on hydraulic anti-roll and end-of-stroke damping.

The repeated crossing out of words p. 99 suggests a working document, written quickly, probably to clarify internally a distribution of tasks between road tests and stationary tests. It follows the logical sequence of reflections on the AP suspension, where the question of vibratory comfort was already in its infancy.

The name of Mr. de Lassus, omnipresent here, probably makes him a key collaborator in this phase of vibration research in 1967, although no other archive in the corpus currently allows his exact role to be confirmed.