Tatra T77

The Czechoslovakian Tatra T77 is the first serial-produced truly aerodynamically designed automobile. It was developed by Hans Ledwinka and Paul Jaray, the noted Zeppelin aerodynamic engineer. Launched in 1934, the Tatra T77 is a coach-built automobile constructed on a central tube-steel chassis and is powered by a 75-horsepower rear-mounted 3.4-liter air-cooled V8 engine. It possessed such advanced engineering as overhead valves, hemispherical combustion chambers, dry sump, fully independent suspension, rear swing axles and extensive use of lightweight magnesium-alloy for the engine, transmission, suspension and body. The latter model T77A has a top speed of over 150 km/h due to the advanced aerodynamics which delivers an exceptionally low drag coefficient of 0.212.

History
The Tatra Company began manufacturing cars in 1897 in Kopřivnice, Moravia, today's Czech republic, making it the third oldest automobile manufacturer in the world. During the time the company lured many genius minds of automotive history, including Hans Ledwinka, Erich Übelacker and Paul Jaray, who all took part in designing Tatra 77.

Paul Jaray and Tatra V570
Paul Jaray first worked at Luftschiffbau Zeppelin (LZ) where he gained experience with aerodynamic design of airships. He used his access to LZ's wind tunnels and subsequently he established streamlining principles for car design. In 1927 he founded company specializing in development of streamlined car bodys and selling issuing licences to major vehicle manufacturers including Tatra. Tatra was the only manufacturer that introduced Jaray streamline principles into their series car production, starting with the Tatra 77.

Before designing large luxurious T77 Jaray himself designed an aerodynamic body for Tatra 57, a mid range model. This prototype wasn't developed any further and didn't reach production, instead Jaray later constructed first and second prototype baring name Tatra V570. This one was more fulfilling Jaray's streamlining principles with more aerodynamic, beetle-shaped body.

Decision to make luxurious state-of-the-art car
However at the time Tatra already had cheap well selling car in its production range, which was moreover popular due to its continuation of simple and ultrareliable tradition started by model Tatra 11. Although the management saw advantages of Jaray's concept, they believed that the new model will be only an additional model with limited production - which meant that it should be aimed at the top of automobile market. The Ledwinka's team subsequently stopped work on V570 and concentrated on designing large luxurious car. Tatra aimed at making state-of-the-art car that would be fast, silent, stable, economical and built to the most rigorous engineering standards as well as reflect modern aerodynamic research.

Public response
Hans Ledwinka was the chief-designer responsible for the development of the new car, while Erich Übelacker was responsible for the carrossery. The development was very secretive until the last moments of the official presentation of May 3, 1934 at Prague motorshow. The car was demonstrated on the road from Prague to Karlovy Vary, where it easily reached 145kmph and amazed newspapermen with great handling and comfortable ride at speeds of about 100kmph. The same year was the T77 presented at Paris motorshow where it became the center of attention not only due to its atypism, but also due to its performance. There were even demonstration rides after the ability of the car with mere 45 kW of engine power to reach 140kmph was doubted, as normally at the time a car to reach such a speed needed about twice as much horsepower. Director Maurice Elvey was so amazed by the looks of the car that he ordered a few of them to take part in his sci-fi movie The Tunnel.


 * ''"It is sensation when it comes to its construction, to its appearance and to its performance. However, it isn't a sensation that would just fall down from the skies, but a logical continuation of the road, which Hans Ledwinka took thirteen years ago. The ideological principle of the new Tatra is an understanding, that the car is moving at the divining line between the ground and the air. ... The car maintaned 145kmph, it has astonishing handling, it drives through the curves with speeds that are both mad and safe, and it seems, that it is only floating on whatever road. ... It is a car, which opens new perspectives to the car construction and automotive practice." Vilém Heinz, Motor Journal, 1934
 * "That is the car for my highways!" Adolf Hitler to Ferdinand Porsche See Volkswagen controversy

Notable owners
The Tatra T77 was the particular favourite of Tatra design engineer Erich Übelacker, who owned and used a T77 himself since 1934. Other famous owners of T77s were Milos Havel, the proprietor of the film studios in Prague who bought a T77 in 1935, Austrian car designer Edmund Rumpler, who designed the aerodynamic Rumpler Tropfenwagen in 1921, Edvard Beneš, the 1930s minister of Foreign Affairs and later president of Czechoslovakia, who both owned a T77A.

Design
A number of designers around the world were trying to construct an aerodynamic car at the time, but Tatra was the first one to successfully introduce it into serial production. There were numerous reasons why Tatra designers took such a revolutionary way of new car conception: First of all it was the aim to reduce drags, mostly the air-drag, which rises by second power of speed and therefore a car with common type of carrossery of the era needed very powerful engine to reach higher speed. The Tatra's new carrossery was tested in wind tunnel. However the new type of carrossery required change of whole car's conception.

The requirement of small front face area limited the car's height, which in turn required a use of flat floor. That led into putting the engine to the rear of the car, directly to the driven axle. Subsequently there was no more need for the floor tunnel with drive shaft and exhaust pipe, which attributed to weight loss. As the designers wanted to reduce the rolling resistance, they  did their best to produce engine as light as possible - air cooled V8 with crank case was made from electron. The transmission box was made from electron as well and it was positioned behind the front axle.

The rear position of the engine was favourable for the air cooling, while in the front of the car there was the oil cooler, accumulator and spare wheel. The frameless carrossery was characterized by the central tube, which was firmly welded to the floor and which covered the draw-bars to brakes, gear control etc.

The front of the car has basically rectangular cross section and in front it is rounded into the level of floor. The front bumper is covering front rounded fenders, while the lower half of the lights is embedded in the front bonnet. The rear of the car is slowly falling down, it is divided by low vertical area and finished by trailing edge. The rear wheels have aerodynamic covers. The door handles are embedded into the carrossery, from which only the door hinges stood out a little.

The first prototype of 1933 had front window of two parts with arrowy positioning, while other prototypes had it from one piece or from three separate pieces of glass, with the two side parts angled to knot together with the carrossery.

The air was streaming to the engine by vectangular ventilation inlets behind the side windows and it was leaving car through rear ribbing. At the time Tatra registered numerous patents considering the air flow to the rear engine compartment, which demonstrates how intense the work on this issue must had been.

Later the rear part of carrossery was enlarged so that both the rear fenders and door hinges were embedded into the carrossery itself. The air was flowing through transversal inlets, which were raising above the rear rounded roof. The trailing edge was highened.

Tatra 77a
In 1935 the T77 was updated and improved which resulted in the T77a. The capacity of the V8 was increased to 3.4 litres. This was achieved by enlarging the bore diameter from 75 to 80mm. This increased the output to 75 hp and the maximum speed to 150kmph. The front now had three headlamps of which the central unit was linked to the steering on some models, making it possible to turn this lamp with the steering. Some T77's and T77a's were also equipped with canvas Webasto roofs. The smooth body of the T77a gave a coefficient of aerodynamic drag of 0.212. An incredibly low value even for today's cars as only a few modern prototypes are able to achieve this figure.

Versions
Tatra 77 was hand built car with finest leather interior. Some cars had a glass wall between the front seats and the rear seats. There was sliding roof available.

An interesting feature equipped on a few of the T77 models was the steering wheel in the centre of the dashboard. The front seat passengers where seated on either side of the driver and the seats placed slightly back. All other T77's had the steering wheel on the right hand side as they drove on the left-hand side of the road in Czechoslovakia before W.W.II, like in various other European countries.

The very unique is the testing twodoor coupe used by Erich Übelacker. This one also had more powerful engine from latter Tatra T87.

Further development
Ledwinka was not entirely satisfied with the T77's handling, caused by its rather heavy rear. He started work on a successor to the T77, which was to be less heavy and with an improved weight distribution. Tatra did just that and in 1936 they introduced the now famous Tatra T87.