ELV 1004 servo-assisted return steering: Magès' note and enthusiastic test (8 July 1966)

In this document

Magès' note (p. 89)

Paul Magès addresses Mr. Henry-Biabaud regarding a test car, the ELV 1004 (DX), equipped with a so-called "servo-assisted return" steering system.

He specifies the settings:

• This steering is more direct than the production version: 1h20 of steering lock to the right and left against 1h35 for the production model.
• It remains less direct than the one tested by the recipient on 1.11.64 on the ELV 1028, which provided 1h.
• The efforts are greater on the road and in corners.
• The speed of return has been braked, a point that Mr. Henry-Biabaud had noted himself.

Magès concludes that this is not the final setting, as the team is awaiting "new cams". The note is signed with an illegible initial and dated 8.7.66, with the mention "TSVP" (please turn over) referring to the following page p. 89.

Mr. Henry-Biabaud's test report (p. 90)

The test took place on 9 and 10 July 1966, over 470 km, between Paris, Lisieux, Caen, Houlgate and a point noted as "P[on]t Aussenon" [uncertain], under "variable weather conditions".

The technical settings tested are noted briefly: "cam with flat", "return brake with flow (variable with steering wheel angle, constant with slope)", and "increased efforts" p. 90.

The feedback, quoted in inverted commas, is enthusiastic: "As it is, I liked this steering a lot." He highlights the usefulness of armrests against the steering wheel's tendency to turn under the weight of relaxed arms, wishes for equivalent comfort for the foot control, and believes that "placing one's wheels well is becoming easier and easier [...] and it is certainly the future". Finally, he notes that parking operations are "perfect", but regrets not having found a suitable surface to test skidding and wheel spin in safety p. 90.

Context

This correspondence is part of the research conducted at Citroën on power and servo-assisted steering, a direct extension of the onboard hydraulic work that characterizes the DS. The principle of a "return" steering system aims to reduce effort and the sensation of feedback at the steering wheel while maintaining tactile information from the road — a central issue in the history of automotive power steering in the 1960s-1970s.

The acronym "ELV" likely designates test vehicles ("essai limité en version" or equivalent, not specified in the document), a common practice among manufacturers to test experimental solutions before industrialization.

Archivist's perspective

This document clearly illustrates Magès' working method: an iterative dialogue between the engineer and a trusted test driver, with successive adjustments of settings (cams, return brakes) based on real-world road feedback p. 89-90.

It seems that Mr. Henry-Biabaud had already participated in previous tests on this type of steering, as Magès recalls by mentioning the test of 1.11.64 on the ELV 1028 p. 89 — which suggests a sustained collaboration over several years.

This document can be compared with the road test of 2 to 5 April 1962, which already focused on a "100% servo-assisted" steering system, testifying to the continuity of this research over nearly four years at Citroën.