Salmson S4

Salmson had emerged as an automobile manufacturer between 1919 and 1922, having already become well established in the aviation business, initially as an aircraft manufacturer and specialising more recently in aircraft engines. Moving quickly beyond the British designed cyclecars, with which the post-war automobile business had started, during the mid-1920s the manufacturer specialised in small cars with technically advanced features such as a twin overhead camshaft and overhead valves for the car engines. In October 1928 the manufacturer had staged a surprise at the Motor Show, presenting the "Salmson Type S" with a small 6-cylinder 9 CV engine incorporating, as on Salmson's existing 4-cylinder engines, a twin overhead camshaft. From the outside the car could be distinguished from Salmson's existing four-cylinder cars only by the "Six" logo in the centre of the front grill. The year before the Great Depression may not have been the best time for the manufacturer to push upmarket, and the "Type S" did not sell in huge numbers. It nevertheless can be seen as a precursor to the Salmson S4 that appeared (with a four-cylinder engine) in 1932. The Salmson S4 both inherited and reinforced the company's strong technical reputation. == Model evolution ==

Salmson S4-C 8CV (1932–1934?) The car was launched in the autumn of 1932 with a 4-cylinder 1465 cc (8CV) engine for which a maximum output of at 3,800 rpm was claimed, supporting a listed top speed of . Suspension was based on rigid axles front and back with longitudinal leaf springs, semi-elliptic at the front and attached using demi-cantilevers at the back. The four-cylinder engine retained its twin overhead camshafts, and the length of the piston stroke was unchanged, but a further increase in cylinder bore (diameter) provided for a further increase in capacity, now to 1731 cc. The cylinder head now featured hemispherical piston heads and centrally positioned spark plugs, which gave the engine a level of responsiveness not normally associated with a 10CV engine. The car shared its place in the 10CV tax band with the recently introduced Peugeot 302. Where comparably bodied versions existed, however, the Salmson S4 DA was nevertheless priced approximately 50% higher than the Peugeot 302: there was evidently no need for Salmson to compete on price with the volume automakers. By now the S4 had acquired independent front suspension, using a transverse leaf spring. The back wheels were, as before, attached to a rigid axle suspended with longitudinal leaf springs. At the 30th Paris Motor show in October 1936 the car was offered in bare chassis form at 24,000 francs. A four-seater 2-door "coupė" bodied car was priced at 31,500 francs while the sedan/saloon bodied car – now described not as a "berline" but with the more traditional term "conduite intėrieur" came in at 32,800 francs. As before, the saloon/sedan bodied car had a sedate old fashioned appearance that offered no hint of the modern technology underneath. The "roadster" was priced at 35,500 francs and the four seater cabriolet at 35,900 francs. In every case, the price included a four-speed manual transmission (brought in from Delahaye), but for an extra 1,500 francs customers could specify a "Cotal Preselector transmission". In the immediate aftermath of the economic depression that hat hit western economies in the aftermath of the 1929 Wall Street crash, price inflation had gone into reverse and the domestic purchasing power of the French currency had begun to increase. The mid 1930s saw renewed economic paralysis in France, however, and during the second half of the decade price inflation returned with a vengeance. The Salmson S4-DA which the manufacturer had adverstized in bare chassis form for 24,000 francs in October 1936 was priced, in January 1938, at 31,200 francs: there were equivalent price increases for cars with bodies fitted. Salmson S4 E 13CV (1937–1951) The star of the Salmson stand at the 31st Paris Motor Show in October 1937 could have been the Salmson S4-E. The car's four-cylinder 2312 cc power unit extended the S4 range upwards, into the 13CV category. In fact, the car was placed at the far end of the stand without fanfare and without any accompanying publicity campaign, so that many visitors to the show likely missed it completely. The S4-E incorporated the technically advanced features of the S4 DA such as an engine with twin overhead camshaft, hemispherical piston heads with the centrally positioned spark plugs. The chassis featured rack and pinion steering, with independent suspension at the front. However, the front suspension was now refined through the addition of longitudinal torsion bars, an approach probably copied from the Citroën Traction that had appeared the year before. Commentators noted that the new engine and suspension enhancements gave rise to a combination of performance and road-holding that was among the best in class for the time. Another novelty for the S4-E was a hydraulically controlled brake circuit in place of the then conventional mechanical linkage. The wheelbase was extended by . Three standard bodies were offered. The "faux-cabriolet" (rebaptised "coupé" in October 1938) 2-door four seater was listed in October 1937 at 49,800 francs. The Berline, still listed as a "conduite-interieure" bodied car was priced at 50,900 francs. The rear doors on this car were hinged at the back: when two doors on the same side were opened there was no central pillar to impede access. The four-seater cabriolet was priced at 54,800 francs. As on the 4-cylinder S4-DA, customers were able to choose between a classic 4-speed manual transmission and a “Cotal Preselector transmission", but whereas S4 DA customers were expected to pay an extra 2,000 francs for the Cotal option, the Cotal transmission was now offered at no additional cost to S4 E buyers. Salmson S4-61 10CV (1938–1942, 1946–1952) The Salmson S4-61 replaced the S4 DA for 1939. Technically very little changed. ==Second World War==

The technically sophisticated S4 was too complicated to interest the military and the manufacturer's Billancourt factory was too small to be listed for a switch-over to war production. Production seems to have been drastically scaled back, during the early years of the war, but sources are vague on the extent and nature of any manufacturing activity, which presumably was further inhibited by the British bombing of the plant on 3 March 1942. At the end of the war, however, it was single-seater racing cars based on the chassis of the Salmson S4-61 that were supplied for the activities of the "Union Sportif automobile" which launched a competition driving school in 1945. This venture did not endure beyond 1946, but the Salmson S4-61 did survive the war. ==Postwar==

Salmson S4 production 1946–1949 (S4-61 and S4-E combined totals): 1946 – 75 1947 – 143 == British Salmson ==

The S4-C was also produced by British Salmson as a 12 HP model. A British Salmson S4-61 cabriolet can be seen in the television series Agatha Christie's Marple in episode 2 of series 1, "The Murder at the Vicarage", at the 9' 39" mark, and subsequently several times in the episode. ==Sources and further reading ==

• Salmson. La belle mécanique française, par Claude et Laurent Chevalier, édition E.T.A.I., 2010.