Андрей Ильин

Андрей ИльинАвтоуслуги

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Андрей Ильин : Авто услуги в продаже

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  • Размещено: 05 августа 2013 г., 15:50
    Even though he was a car constructor, Ettore Bugatti gets involved in 1932 in the production of a passenger train with combustion engines for the French government. The project eventually reached its goal and the Bugatti trains became reality. It is often said that Bugatti has decided to design railway engines just to recycle the enormous engines of the partly unfinished Royale cars that were left-over unsold. But when we look at the results, it doesn’t seem to be his only motive. It is true that the company was facing problems but this project must have presented an interesting challenge for Ettore.
    Talking in facts, the Bugatti locomotives served well for many years on the French railways and even achieved a speed record of 196 km/h in the category of no-steam engines. They were powered by 4 motors Bugatti Royale (same as these used in homonymous Bugatti cars) of 11000 cc. and 200 Hp. joined to the transmission by hydraulic couplings. The Bugatti trains were a real success and Ettore probably felt some sort of satisfaction after the commercial failure of the Royale cars.
    While his father was busy designing the train, Jean worked on the 57 or, as chance would have it, the most successful Bugatti car ever.

    Jean’s Bugatti
    The Bugatti 57 was officially presented on the Paris motor show in 1934. The model was launched in three versions: a 4-door sedan called “Galibier”, a 2-seat coupè “Atlante” and a 4-seat convertible called “Stelvio”. Then in 1936, the model 57 was also presented in a version with the “S” type chassis. The range of bodies offered by Bugatti expanded by the introduction of a 2-seat spider “Aravis”, a 2-door 4-seat “Coach ventoux” and a super-racing “Atlantic” based on the model “S”. The last body typology, a cabriolet called “Aravis”, was presented in 1938.
    The bodies were designed by Jean and his colleagues and physically produced by Gangloff Fréres. Needless to say that it was possible to order the chassis separately and later choose the body constructor of one’s preference.
    The 57 is equipped by an 8-cylinder in-line engine of 3300 cc. with fixed heads integrated into the engine block. The engine block is based on a scheme that became typical for the last generation of Bugatti engines. With its fixed heads and double camshaft it is in some details similar to that of the model 50, but it has 6 main bearings. The cylinder barrels are practically subdivided in pairs of two along the block and there is a main bearing in the space between each couple. The last two bearings are at the rear, very close to each other.
    The block of fixed heads offers many advantages but its maintenance is difficult.
    One of the most delicate and complex tasks is for example the recalibration of the cylinders or better the adjustment of the cylinder barrels.
    The 57 has a valve gear with a double over-head camshaft and 2 valves per cylinder. The control of camshafts consists of a train of straight-cut gears placed in the rear part of the engine next to the flywheel and the clutch. The gearbox is directly connected to the engine block and not joint with the differential gear. It was the first use of such solution in a Bugatti car.
    The choice to place the valve train in the rear part of the block near the flywheel helps to reduce the effects of the drive shaft’s torsion on the valve gear itself. But it causes a further complication, as one more main bearing must be added between the first straight-cut gear of the valve train and the engine flywheel that naturally requires an appropriate support. That is why there are two main bearings so close to each other.
    Furthermore, the valve gear train of the 57 presents a solution that was used for some period also by the other car designers of this era. Its intermediate straight-cut gear was not made of metal but of synthetic fibre. This element made it possible to significantly reduce the general noise level at the cost of reduction of reliability. Its life was indeed limited to about 30.000 miles (less then 50.000 km) and the fact that it didn’t warn you by any suspicious sounds until the very moment it got broken was surely another disadvantage. If this straight-cut gear broke up while the engine was running, the consequences as you may imagine were disastrous particularly because of the fact the engine valves were arranged in an inclusive angle of 96°. At the moment of failure, the valve gear train stopped and the valves that remained open then inevitably crashed against the pistons. While the maintenance was expensive, to fix such damage posed an enormous expense. But it is needless to say that the luxury of owning and maintaining a Bugatti was always reserved to a very few rich.

    Miller's school

    The double camshaft solution was used for the first time on Bugatti model 51 made in 1929 and it later appeared on the exceptional 55 and 50, partly as a result of Jean’s effort to renew the engines and make them more competitive. It has been proved that the design of Bugatti’s double-shaft head directly derives from the scheme used in American cars Miller. Bugatti has even exchanged his three 49 for two Miller cars in an arrangement with the American driver George Stewart (alias Léon Duray) who brought these cars to France for racing. These were two Miller type 91 with front-wheel drive, 4-cylinder 1500 cc engine, DOHC and centrifugal supercharger.
    People at Bugatti examined the Miller engine and substantially copied its basic architecture. They even experimented with the centrifugal supercharger that was very popular with the American racing cars, but eventually returned to the type “Roots” that was more suitable for European race-courses.
    But the valve timing of the 57 was right from the first version different from the double camshaft used in models 50, 51 and 55. In these cars based on the Miller scheme, bucket tappets were used between valves and camshafts while the 57 returned to the use of finger equalizers. Placing the finger equalizers between camshafts and valves can be more or less advantageous depending on the general project and implementation. The grand prix Mercedes were successfully using a similar system and you can still find it in the modern production. Generally speaking this solution should allow the use of cams with less “pushed” profile and higher maximum rotation speed, but it brings a lot of complications that could have been avoided in the model 57 by using a more simple and reliable scheme, such as the bucket tappets.

    The 57S
    The version “S” of the 57 chassis was presented in 1936. The “S” stands almost certainly for “Surbassè” (“reduced”) and not, as it is generally thought, for “Sport”.
    The 57S are easy to distinguish from the “normal” 57. They have a different, V-shape, radiator cowling and a paricular design that joins the profile to the bonnet and the shoulder-line. Apart from that, the bonnet is at the same level with the mudguards, which makes the car look more flattened and broad. In some versions, the mass of headlights is connected with the mudguards and it makes the car look even lower and more aggressive.
    The chassis of 57S bears a very particular characteristic: the two main longitudinal frame members are in the rear part perforated, matching the axle shafts. This lets axle shafts pass and swing through the two frame members and allows a remarkable reduction of the car’s height.
    In some models of the version “S”, the engine is “flexibly” connected to the chassis using a simple and ingenious system. In this solution, a plate with protrusions was “sandwitched” between the engine block and clutch bell. The protrusions then fastened everything to a crossing component of the chassis equipped with the silent blocks.
    In the “S” version, the engine of the 57 has usually a higher compression ratio which helps to raise the horsepower to aproximently 180 Hp.

    The supercharger
    All the 57 had the possibility of being equipped by the centrifugal supercharger, type Roots. Their type inscription would then change to 57C or 57SC in the “S” version. The customers could order the car with the pre-installed supercharger or choose to install it later, which was really more common. It seems that only very few cars left the factory with the pre-build supercharger.
    The horsepower of the supercharged engines would climb to about 200 Hp, allowing the car to reach 200 km/h. This was making the 57 one of the fastest cars in the world.
    The beautiful dark blue “SC” model Atlantic that is shown on this page represents the highest essence of racing-spirit and originality of Bugatti 57. The car is now in American hands and has been completely refurbished. It won the prestigious “Best of Show” price in the Pebble Beach contest in 2003.

    The exceptional Atlantic
    The 57 Atlantic is surely the most spectacular of all Bugatti. The car has been produced in just three exemplars, all of which reached the present days. One of them has been almost completely reconstructed after a serious accident; as a result, there are only two cars really close to the original. And their value is naturally enormous.
    While the Atlantic has the same chassis as the “S” models, its body is completely different from all the others types. It gives an impression of being composed of two symetric shells joined in the central part by a series of riveting that run along the upper surface flange as the mudguards do. This may sound complex but a single look at the picture makes everything clear. A hard to believe legend sais that the real motive for such a unique solution was the intention to make the body from a special light alloy called “electron” that is presented in some components of Alfa Romeo 8C 2900 engines. But as it was hard to weald it, it was decided to connect the body parts with the rivets. As for the facts, there are no traces of any special kind of light alloy on any of the three cars; all their alluminum parts are made of a similar material as many other bodies.
    Apart from that, the wealding of the light alloy with the wealding torch was already a well known technique in the 30’s, and even if there ever was a body made of a special difficult to weald metal, these few rivets wouldn’t surely solve the problem. As a metter of fact, when you construct a car body there are much more parts that need to be bended and wealded together than it may seem (or than we are made to believe).
    Whether the “electron” body legend is true or not, the 57 Atlantic does not loose any of its charm anyway. Just have a look at it!
    Bugatti car. 1932Bugatti car. 1932


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