Soletta 750
Two-door four-seater concept Soletta 750 was developed by Swiss designer Salzmann. The rear wheels were driven by a four-stroke twin-cylinder engine, mounted in front of the patented rear axle.
Swiss engineer Willy Ernst Salzmann graduated from the Zurich Institute of Technology. While still a student, he designed a sophisticated three-wheeled vehicle and after graduating he founded his own vehicle design company in Solothurn, Switzerland. The company became well-known and respected, especially for its designs of equipment for Ford and Ferguson tractors.
Salzmann also designed a new type of rear-wheel suspension for cars, called Zweigelenk-Elastikachse (double-jointed elastic axle). The key elements of the suspension were a fixed or semi-fixed differential with swing axle half-shafts and coil springs, the half-shafts being connected by a crossbar suspended below the differential and attached to the shafts by rubber springs.
Salzmann wanted to display this original suspension in the main hall of the 1955 Geneva Motor Show. However, he was told that this main hall was reserved for complete vehicles only and his exhibit had a place in the hall dedicated to parts and accessories. Therefore, Salzmann decided to build a concept of a car with this rear suspension so that it could be exhibited in the main hall the following year (8-18 March 1956). The name “Soletta” is the Italian name for the Swiss town of Solothurn.
Willy Ernst Salzmann designed a modern two-door body for the four-seater concept with a wheelbase of 2000 mm and external dimensions of 3150 x 1350 x 1380 mm (length x width x height). Several bodies (at least two) were produced by the Swiss coachbuilder Hess of Bellach. The Soletta 750 had a large, forward-tilting radiator grille in the front, incorporating a pair of round headlights and amber turn signals. The flip-up nose replaced the usual front-up hood and allowed access to the spare wheel and small luggage compartment.
The body of the Soletta 750 was made of plastic, except for the doors, which were sheet metal. A rarity was that the doors on both sides were the same to save production costs. Therefore, on the left side, the door handle was in front and the hinges in the back, and on the right side the opposite. The doors were wide enough to allow easy access to the front and rear seats. The vertical aft wall was, like the front, hinged with the hinges located at the bottom and featured circular tail lamps and rear blinkers.
Inside, the Soletta 750 had a simple dashboard with a small panel in front of the two-spoke steering wheel that housed the speedometer. A large open storage compartment formed the bottom of the dashboard. The front seats were split, the rear bench seats.
Powering the rear wheels of the Soletta 750 was a four-stroke, air-cooled, flat-twin petrol engine with SV valve timing and a displacement of 745 cc (bore/stroke: 78/78 mm). With twin Oensingen carburettors and a compression ratio of 6.3:1, it gave a peak output of 22 hp (16 kW) at 4,200 rpm and 44 Nm of torque at 2,500 rpm. The engine and the manual three-speed gearbox with floor-mounted gear lever were located in front of the rear axle under the rear seats. The engine was supplied by Swiss motorcycle manufacturer Condor. With a kerb weight of around 500 kg, the car had a top speed of 105 km/h.
The Soletta had a chassis with a steel tube upper structure. The front wheels were independently suspended on double transverse triangular arms and sprung by coil springs. The front suspension was probably derived from the Renault 4CV. The rear wheels had innovative independent wheel suspension and coil spring suspension. The brakes were drum brakes on all wheels.
The first Soletta 750 concept debuted at the 1956 Geneva Motor Show and differed from the concept described above mainly by its panoramic rear window, different front grille and black painted bumpers and lower part of the doors. Public reaction was largely favourable and the car was praised by Sir Alec Issigonis, later creator of the legendary Mini. Renault, Alfa Romeo and a government agency from the GDR also expressed interest, but mass production did not take place.
The only surviving example of the Soletta 750 was exhibited in 2015 at the Pantheon Basel automobile museum in Muttenz, in 2018 at the Geneva Motor Show and in 2020 at the Transport Museum in Lucerne. From November 2023, it is on display at the Derendingen Technology Exhibition in Derendingen, Switzerland.
