Paul Magès (1908-1999): biographical notice of the inventor of the hydropneumatic suspension

In this document

A self-taught man who became "Mr. Hydraulics"

The notice retraces the career of Paul Magès (1908-1999), who was initially supposed to join the Académie des Arts et Métiers in Marseille but had to leave high school at 17, "coming from modest parents" p. 12. Hired at Citroën, he climbed the ranks as a self-taught man, reading "all the technical manuals he could find", and became a technical writer and then deputy head of the Super-Control p. 12.

The brake limiter

In 1939-1940, tasked with correcting a defect in the TUB van (locking of the rear wheels when empty), Magès invented a brake fluid pressure limiter based on the load on the axle. Impressed, Pierre Boulanger transferred him to the design office as "Mr. Hydraulics" p. 12.

The hydropneumatic suspension

The document indicates that Magès, convinced that a gas "500 times more flexible than steel" is the key to an ideal suspension, presented in 1944 to André Lefebvre a first version mounted on a TPV, which "broke down after twenty minutes". A new version, tested in 1946, provided "comfort and road holding hitherto unknown" p. 12. Deemed too expensive for the 2 CV, the system was intended for the VGD (future DS). It was Lefebvre who is said to have then envisaged extending the use of pressurized hydraulics to steering, braking, gear shifting and the clutch p. 12.

The pedal and the Diravi

Magès is also credited with the pedal ("mushroom" brake pedal), justified by the fact that it involves opening a pressurized orifice rather than pushing fluid p. 12. Dissatisfied with the DS power steering developed in 1953, he then designed the Diravi, "born as early as 1957", which Pierre Bercot is said to have delayed for fear of disorienting the clientele p. 12.

Context

The document does not specify the detailed technical circumstances of the brake limiter. As for the year Magès joined Citroën, the collection establishes it: he joined in August 1925, at 17 and a half, to remain there for 49 years, as reported by his own autobiographical notes (Draft letter from Paul Magès to Mr. Sarre and interview plan of the 11...).

For the record, the DS was presented by Citroën in 1955 and the Diravi effectively equipped the DS from 1957, which corresponds to the chronology mentioned; this general knowledge does not come from the document but from the known historical context of the brand with the chevrons. The collection also makes it possible to specify the technical genesis mentioned here: the plans for hydropneumatic suspension with differential interaction date from 17 February 1944, and the first tests of the 2 CV with hydropneumatic suspension took place from May to July 1946.

Archivist's perspective

This biographical notice, published in 2019 in a special issue of La Vie de l'Auto, offers a clear synthesis of Magès' career, probably intended for a non-specialist public discovering the great Citroën inventions.

It usefully sheds light on the Magès collection as a whole: the Hydraulics Quiz no. 5, devoted in particular to the Diravi, extends in a more technical way the inventions summarized here in general public language. Similarly, the leaflet "Forty years of innovation in hydraulics" seems to echo, on the scale of the company, this individual trajectory.

It should be noted that the page brings together two distinct notices (Magès and Jacques Wolgensinger), a sign that this special issue draws up a gallery of figures who have marked the history of Citroën, engineers as well as communicators.