In setting there W196R he proposed again the dilemma of the position of the engine. The designers were largely the same as the big hits of the 1930s, so they knew the dynamic front-engined single-seaters. Certainly they evaluated the hypothesis of positioning the engine behind the pilot, the calculations foreshadowed its greater potential, but some aspects remained that were not well quantifiable. He will reveal it in an interview of the time, eng. Hans Scherenberg one of the project leaders: it was feared that the decrease of moment of inertia, consequent to the centralization of the engine, made the car so responsive to put the pilot in difficulty in the search for the limit, also considering his own driving position much more advanced than usual. How much would have been lost due to these critical issues and how much fine-tuning would it have taken to eliminate them? They were unknowns. In the end we chose the configuration with the front engine, positioned as usual as close as possible to the cockpit, but with the novelty, for F1, of mounting it at an angle. In addition to the aerodynamic advantages already mentioned, there was that oflowering of the center of gravity, a very influential aspect given the limited width of the carriageways in use at the time. Reconfirmed the weight distribution, with the most relevant mass, the reservoir fuel, in the tail, close to the seat. Others were moving it to the sides but at Daimler-Benz they did not want to lose in terms of traction, on the contrary they also moved the exchange putting it overhanging instead of within the axes. Returning to the tank they made it with one very elaborate shape, by welding light alloy sheets, to occupy any available space around the rear inboard brakes and gearbox. It was designed to be rigidly fixed (not with the usual bands) to the frame, therefore with one structural function to save some bracing. It has a capacity of 210-220 liters, a volume that they installed without affecting the very tapered shape of the bodywork. For races with higher consumption, it was possible to add an additional tank on one side of the cockpit. As for the oil tank, on the Streamliner it was placed laterally on the left, while on the narrow version, at the end of the tail, fixed to the fuel tank. For the chassis the type of structure already used was chosen with satisfaction on the sport W194, the lattice of pipes of small section in high resistance steel.
It was there emerging typology, compared to that in force a tubular side members. In the case of the W196R, albeit with a lower weight, only 36 kg, it improved both the torsional and flexural stiffness of the previous frames. At Daimler-Benz the calculation methods had been perfected and the flexural-torsional checks on scale models were consolidated. The arrangement of the triangulations in the access area to the passenger compartment, a weak zone from a torsional point of view. These are patterns that will become common in the following years. In the first racing season there were no major changes to the chassis, while in the second there were 2 versions a shorter wheelbase to improve handling on winding slopes. Turning to suspensions, let’s start from the front one. The designers kept the pre-war scheme, that is the deformable parallelogram with superimposed triangles, but with the important novelty of the drum brakes inboard. A solution not new but introduced for the first time in F1, which brought several benefits: lightening of the unsprung masses, less heat transfer to the tires, the possibility of optimally positioning the steering axis and the use of more generously sized drums. The only flaw, the slight increase in weight, due to joints and drive shafts. In the shorter wheelbase version (like Montecarlo ’55) the front brakes were moved around the rim both because the drive shafts could not be worked with excessive offset, but also because of the resulting lightening. In that version it was one of the priority objectives, also sought after with other pieces specially built with special materials, such as the triangles of the suspension in titanium instead of steel.
Returning to the suspension, like elastic element he chose one torsion bar keyed directly to the lower triangle by means of a coaxial sheath which extends its length at the front. It is a solution that may have inspired Chapman for the 72. Torsion bars were still quite popular at the time along with the De Dion bridge at the rear. Here, however, the Daimler-Benz designers switched to some independent suspension, declined according to an original scheme single arm. There was an industrial interest in this configuration to the extent that some aspects of it were protected with patents. Something conceptually similar was in fact used on their sports series cars. This type necessarily requires that the single-arm is supportive with the upright, the W196R is no exception, but it has a unique fulcrum, for both sides, placed at the bottom under the drums. That of the only fulcrum is a choice that makes it coincide with the roll center, with the advantage that the lateral lying in the curve of the frame does not produce variations of Camber. In addition, the very low position of the roll center also had to ensure effective oversteer contrast. Also for the longitudinal constraints an interesting geometry was chosen: the 2 symmetrical arms form aWatt’s articulation and this ensures that the wheel does not change the toe-in during the travel of the suspension, in practice it does not self-steering. At the time, however, there had been some doubts as to whether to leave the De Dion bridge which had worked well in pre-war models, but in the end the belief to change prevailed because the performances were estimated to be similar, but with the choice of positioning also at the rear inboard brakes and cantilever gearbox, the new solution fit better, it was more light and especially less bulky, to the advantage of the positioning of the tank. Also at the rear, a torsion bar was chosen as the elastic element, this time with a linkage to connect it to the single arm. From the ’55 British GP, one has been added coil spring, lockable, interposed between the end of the lever Vt , the one that binds the bar to the frame, and the frame itself. It was used to adjust the stiffness of the suspension to the fuel load which went from 180 kg to almost zero: up to the middle of the race the spring was canceled with a hydraulic piston in parallel, then the pilot released it by making it work in series with the movements of the torsion bar. Thus the suspension became more flexible and adequate to mass reduction on the rear axle. An interesting trim corrector.
For the shock absorbers they used the hydraulic ones but with telescopic drive, a typology that was spreading. Finally a note on the cooling system of the self-ventilating brakes. The designers drew on the surface of the drum a dense series of parallel channels, with the radial inlet and outlet to activate the circulation push centrifuge. To complete the ventilation, it was enough to prepare vents on the bodywork to evacuate the hot air, as in fact was done on the tail. In front of it no problem, the drums are also hit by the air coming out of the radiators (water and oil), which, although hot, still has a cooling effect due to the high temperature differential.
Technical data:
Builder: Daimler-Benz; template: W196R; year: 1954;
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project leaders: ing. Hans Scheremberg, ing. Rudolf Uhlenhault;
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frame type: trellis steel pipes Ø20-25mm, th. 0.8-1.0mm, welded;
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fuel tank: 1 in queue 210-220 L.;
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oil tank: 1 in the tail (lateral Streaml.), 40L .;
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front suspension: quadrilateral def., overlapping triangles, b. of torsion .;
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post suspension: single-sided, b. torsion (+ coil spring in series in ’55);
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shock absorbers: telescopic hydraulic;
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uprights: in steel;
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circles: with spokes, stud fastening;
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brakes: drum, ant. Ø350mm, post. Ø275mm, self-ventilated;
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brake position: inboard (front outboard in the 2150mm wheelbase version);
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brake booster: Ate, in ’55;
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step: 2350 mm; 2210 and 2150mm in ’55;
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front carriageway: 1330 mm; rear carriageway: 1358 mm;
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Length: 4160 mm (Streaml.); length: 1625mm (Streaml.);
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car body: removable, light alloy;
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radiators: 1 water, 1 oil, front;
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tires: Continental, ant. 6.00 × 16, post. 7.00 × 16;
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total mass: 650 kg. dry, + 50Kg Streamliner.
In the next installment we will analyze the engine and transmission.
Historic Formula 1 technique: Mercedes-Benz W196 R (1954) – Part one
Technique of historic Formula 1: Mercedes-Benz W196 R (1954) – Second part
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