Citroen 7 CV

Citroen 7 CV

MotorClássico, Lisbon, Portugal

in Wikipedia

Traction Avant monocoque

Entrance torsion bar suspension

The Traction Avant, French for “front wheel push”, was developed by André Lefèbvre and Flaminio Bertoni in late 1933 / early 1934. Though not the very first manufacturing front wheel push car or truck – Alvis crafted the 1928 FWD in the British isles, Cord manufactured the L29 from 1929 to 1932 in the United States and DKW the F1 in 1931 in Germany – it was the world’s very first front-wheel push metal monocoque manufacturing car or truck. Along with DKW’s nineteen thirties products, the Traction efficiently pioneered front-wheel push on the European mass car or truck market place.

The Traction Avant’s structure was a welded monocoque (unitized physique). Most other cars of the period had been based mostly on a separate frame (chassis) onto which the non-structural physique (“coachwork”) was crafted. Monocoque development (also referred to as Device Overall body or “Unibody” in the US currently) effects in a lighter auto, and is now utilized for practically all car or truck development, while physique-on-frame development stays suited for greater vehicles this sort of as trucks.
This technique of development was seen with wonderful suspicion in many quarters, with doubts about its strength. A style of crash test was conceived, using the form of driving the car or truck off a cliff, to illustrate its wonderful inherent resilience.

The novel layout manufactured the car or truck very small-slung relative to its contemporaries – the Traction Avant constantly possessed a exceptional glance, which went from showing rakish in 1934 to common and fairly outdated fashioned by 1955.

The suspension was very superior for the car’s period. The front wheels had been independently sprung, using a torsion bar and wishbone suspension arrangement,[three] where by most contemporaries utilized stay axle and cart-style leaf spring models. The rear suspension was a basic metal beam axle and a Panhard rod, trailing arms and torsion bars connected to a three-inch (seventy six mm) metal tube, which in convert was bolted to the monocoque.

Given that it was substantially lighter than regular models of the period, it was able of a hundred km/h (62 mph), and consumed gas only at the amount of ten litres for every a hundred kilometres (28 mpg-imp 24 mpg-US).



Traction Avant rear

1937 7C Coupe Traction Avant

A French “familiale” eleven F 1954, 6 windows, 9 seats

Citroën eleven Commerciale 5-door

Traction Avant rears. The boot was lengthened and its volume doubled in Autumn 1952.[four]
The first product, which was presented on eighteen April 1934, was a little saloon with a one,303 cc (seventy nine.5 cu in) motor. This product was referred to as the 7A, which was succeeded in June 1934 by the 7B with a higher-electric power motor of one,529 cc (93.three cu in). The 7B in convert, was succeeded in October 1934 by the 7C with an even higher-output one,628 cc (99.three cu in) motor. Later products had been the eleven (released in November 1934), which had a one,911 cc (116.6 cu in) 4-cylinder motor, and the fifteen (released in 1938), with a 2,867 cc (a hundred seventy five. cu in) 6. The quantities refer to the French fiscal horsepower score, or CV. The eleven was an eleven CV, but curiously the fifteen was truly 16 CV. The eleven was crafted in two variations, the 11L (“légère”, or “gentle”), which was the very same dimension as the 7 CV, and the typical product eleven, which had a lengthier wheelbase and wider observe.

Citroën planned two variants that never ever entered manufacturing, since there was not more than enough funding out there to develop them, other than as running prototype vehicles. 1 was an computerized transmission-outfitted product, based mostly on the Sensaud de Lavaud computerized transmission, the other a 22 CV product with a three.eight liter V8. The transmission (which was truly originally developed for the Citroen) was a “gearless” computerized, using the torque-converter by itself to match motor revolutions to the drivetrain revolutions, a great deal like the Dynaflow Transmission released later in the United states of america. The car or truck was intended to have a much less spartan inside than the other Traction Avants and it was to element Citroën’s possess new V8 motor. About twenty prototypes had been manufactured, but when the undertaking was canceled in 1935 owing to Michelin’s takeover they had been most likely all wrecked.[citation wanted]

In addition to the four-door physique, the car or truck was also manufactured as a 2-door coupé with a rumble seat, as a convertible and as an extended length Familial product with three rows of seats. There was even a hatchback-style Commerciale variant, in 1939, effectively forward of its time, in which the tailgate was in two halves, the decreased of which carried the spare wheel with the higher opening up to roof amount. A just one-piece prime-hinged tailgate was released when the Commerciale resumed manufacturing in 1954 just after currently being suspended for the duration of Globe War II.
Wartime disruption[edit]

In September 1939 France declared war on Germany and in June 1940 the German military rapidly invaded and occupied Northern France.[one] The war several years had been characterised by a determined scarcity of raw supplies for civilian market and of petrol,[one] but these things had been not evident instantly. The Paris Motor Display scheduled for October 1939 was cancelled at brief detect, but Citroën’s possess planned announcements had included the forthcoming 2CV product fairly than any substantial changes to the Traction.[one] For the Traction, the final “normal” yr in phrases of manufacturing stages was 1939, and eight,one hundred twenty of the 2910mm wheelbase 1628cc engined 7C products had been manufactured.[one] This tumbled to one,133 in 1940, which was the very first yr when the plant endured severe air-raid injury – on this event prompted by a German assault – on three June 1940. Manufacturing of the cars was suspended in June 1941, by when a additional 154 had been manufactured in the 6-thirty day period time period just finished. The 7C would go on to seem in Citroën price tag-lists till March 1944, but manufacturing of this smaller sized engined “7CV” edition of the Traction was not resumed just after the war.[one] For the additional highly effective 1911cc engined eleven B-gentle products, the equivalent figures had been 27,473 models manufactured in 1939, four,415 in 1940 and 2,032 for 1941, nevertheless for this product manufacturing in 1941 finished only in November 1941 so the determine for that yr represents eleven months of manufacturing.[one]

In 1945 manufacturing restarted only gradually: the eleven B-gentle reappeared very minimal altered from the 1941 cars other than that headlight surrounds had been now painted fairly than completed in chrome. By the conclude of December 1945 the year’s manufacturing had achieved one,525.[one] Currency depreciation is obvious from the car’s detailed price tag which had been 26,800 francs in January 1940, and had risen to a hundred and ten,670 francs in October 1945.[one] In 1945 the car or truck was the only product out there from Citroën, and as one more indication of the times, customers not ready to supply their possess tires had been charged an more 9,455 francs for a set of 5.[one] In May well 1946, presumably reflecting an easing of the war-time tire scarcity, the car or truck could at final be bought with tires at no more charge, but by now the over-all price tag of an eleven B-gentle had risen to 121,180 francs.[one]

The eleven B-typical product, differentiated from the eleven B-gentle by its 3090mm wheelbase, seasoned a related drop off in volumes concerning 1939 and 1941, with just 341 cars manufactured for the duration of the very first seven months of 1941.[one] Just after the war, a solitary eleven B-typical was manufactured in 1946, in time to be presented at the October 1946 Paris Motor Display: manufacturing crafted up for the duration of 1947, but for the duration of the car’s 10-yr publish-war time period the shorter eleven B-gentle would, in France, go on to outsell the eleven B-typical.

In the beginning the French military lacked enthusiasm for the Citroën Traction, believing that it offered inadequate floor-clearance for their needs.[one] Nevertheless, by September 1939 around 250 had uncovered their way into army services. With losses of cars at the frontier mounting, Citroën supplied a additional 570 to the military concerning February and May well 1940, and subsequent deliveries most likely took spot just before army defeat intervened.[one] All through the war many of the cars had been reregistered with “WH…” (Wehrmacht Heer/Military command) license plates, possessing been requisitioned by the German Military.[one] These gave reliable services the two in France and additional afield, notably in Libya and Stalingrad. Tractions had been also favoured by the Resistance, and as profession gave way to Liberation they turned up all around France with FFI inscribed proudly on their doors. Much less gloriously, the cars had been recognised as favourites amid gangsters this sort of as the then infamous Pierrot le Fou, and his Traction gang.

British isles crafted cars[edit]

Remaining-hand push variations had been crafted in Paris, in Forest, Belgium, in Copenhagen, Denmark for the Scandinavian market place, and suitable-hand push cars in Slough, England. The Slough edition of the 11L was referred to as the Light-weight Fifteen and the very long wheelbase eleven was referred to as the Massive Fifteen. This perplexing terminology referred to the British fiscal tax score of the time, which was higher than the French, so the 11CV motor was 15HP in England. The 15CV product was referred to as “Massive 6” in reference to its 6-cylinder motor. They had been outfitted with the leather seats and picket dashboards well-known in the British isles, had a twelve-volt electrical program and had been distinguished by a different radiator grille and different bumpers. Some products also had a sliding sunroof.
A one,911 cc (116.6 cu in) Light-weight Fifteen analyzed by the British magazine The Motor in 1951 had a prime velocity of seventy two.6 mph (116.eight km/h) and could accelerate from 0–60 mph (97 km/h) in 29.7 seconds. A gas consumption of 25.2 miles for every imperial gallon (eleven.2 L/a hundred km 21. mpg-US) was recorded. The test car or truck charge GB£812 such as taxes.[5]

A 2,866 cc (174.9 cu in) 6-cylinder product was analyzed by the very same magazine in 1954 and for this car or truck the prime velocity uncovered was mph (a hundred thirty.5 km/h), acceleration from 0–60 mph (97 km/h) 21.2 seconds and gas consumption eighteen.6 miles for every imperial gallon (fifteen.2 L/a hundred km fifteen.5 mpg-US). The test car or truck charge GB£1,349 such as taxes.[6]

Citroën eleven CV Légère

The Traction Avant utilized a longitudinal, front-wheel push layout, with the motor set effectively in just the wheelbase, resulting in a very favourable weight distribution, aiding the car’s superior handling properties. The gearbox was positioned at the front of the auto with the motor at the rear of it and the differential concerning them, a layout shared with the later Renault four and 16 and very first era Renault 5 but the reverse way spherical to many longitudinal front-wheel push cars, this sort of as the Saab ninety six and Renault twelve and eighteen and most Audi products. The gear change was set in the dashboard, with the lever protruding by means of a vertical, H-formed gate.[7] Mainly because this vertical orientation could have resulted in the car or truck dropping out of gear when the lever was in the higher positions (i.e., next or reverse gears), the gear change mechanism was locked when the mechanical clutch was engaged and produced when the clutch pedal was frustrated. The outcome of this layout, alongside with pendant pedals, umbrella-style handbrake control and front bench seats, was a very spacious inside, with a flat and unobstructed flooring. The small-slung arrangement also eliminated the have to have for running boards to action into or out of the auto. These features manufactured them excellent for use as limousines and taxi cabs, and they had been quite well-known amid motorists and passengers alike. Right up until 1953, black was the only coloration out there.

Influence on Motorsport[edit]

One more specialized importance of Tranction Avant was the forged aluminium alloy transaxle, which was pioneered by Hans Ledwinka in the early nineteen thirties for Tatra V570 utilized in front of the motor located in the rear, but was quite radical at the time.

As effectively as currently being a considerable portion of the weight financial savings, the manufacturing facility for this transaxle contributed to the down below outlined economic crisis. But when John Cooper looked for a gentle transaxle case for Formula 1 rear motor revolution, Traction Avant device was about the only candidate, as Volkswagen magnesium alloy transaxle was a great deal smaller sized and missing the space wanted to property heftier gears wanted for Formula 1. The Traction Avant transaxle was utilized on Cooper T43 which received a F1 championship race as the very first mid-mounted motor car or truck to do so in 1958, and on its successors Cooper T45, T51 and T53. Cooper T51 received the GP Globe Championship in 1959.

Unlike the Volkswagen alloy case utilized by Hewland, the Traction Avant case could not be utilized up side down, as the enter shaft peak was a great deal higher in relation to the output shaft axis so that the oil amount wanted to lubricate the gears would exceed the then-unreliable enter shaft oil seal peak if utilized upside down. So the motor wanted to sit significant above the floor with the oil sump space down below, which was not wanted by dry-sump racing engines. But the French transaxle was utilized by numerous racing car or truck constructors in the late 1950s to 60’s with several stages of success.

In the case of Jack Brabham, who individually frequented the ERSA foundry in Paris to talk about a risk to fortify the case ,[eight] the transaxle grew to become recognised as “ERSA Knight” with an more spur-gear set mounted in the bellhousing spacer (motor to transaxle adapter) proposed by Ron Tauranac, named for Jack Knight who developed the modification and manufactured the straight-lower gears. The peak offset designed by the spur gear set enabled the motor to sit decreased, and grew to become the purpose why Cooper T53 was referred to as the ‘Lowline’, which not only manufactured Brabham the Globe Champion in 1960 but also grew to become the precursor to the establishment of Brabham as a Formula 1 constructor.

Influence on Citroën[edit]

1954 6-cylinder 15CV with hydropneumatic suspension fitted to the rear wheels – in ‘high’ placement

Traction Avant as modern marriage car or truck

The growth prices of the Traction Avant, mixed with the redevelopment of its manufacturing facility, had been very significant and Citroën declared bankruptcy in late 1934. The largest creditor was Michelin, who then owned Citroën from 1934 till 1976. Underneath Michelin, Citroën was run as a study laboratory, a test bed for their radial tires and new automotive technologies.
In 1954 Citroën’s experiments with hydropneumatic technology manufactured its very first outcome, the “15H” – a variant of the 6-cylinder product fifteen with a self-leveling, peak-adjustable rear suspension, a subject demo for the groundbreaking DS produced the following yr.

Directly just after the introduction of the Citroën ID, a simplified and additional competitively priced edition of the nonetheless groundbreaking DS, manufacturing of the Traction Avant finished in July 1957. More than 23 several years, 759,111 had been crafted, such as 26,four hundred assembled in Slough in England, 31,750 assembled in Forest close to Brussels and one,823 assembled at Cologne in Germany. The full reflects the manufacturing stoppage for the duration of Globe War II.

The Traction Avant currently[edit]

Massive Fifteen sedan

In 2006, the oldest surviving 7A has manufacturing quantity (“coque nr”) AZ 00-eighteen, and is exhibited in partly dismantled condition (motor and front wheels detached) in the Citroën Museum in Paris. The oldest running 7A is most likely quantity AZ-00-23, which was, till one September 2006, in possession of a Dutch owner and is now with a Slovenian owner.
Traction Avants are rather robust vehicles even by modern specifications nevertheless, they are prone to leaking drinking water inside of the cabin and care needs to be taken when purchasing just one. Each and every several several years, Traction Avant fans ship their vehicles to an unique site for a rally. In 2002, for illustration, a team of around thirty Traction Avants drove from Los Angeles to New York with out incident. [one]

Posted by pedrosimoes7 on 2013-twelve-thirty 16:25:38

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