Tatra T77
Encyclopedia
The Czechoslovakian Tatra 77 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 77 is a coach-built automobile constructed on a central tube-steel chassis
and is powered by a 75 hp 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 later model T77A has a top speed of over 150 km/h (93.2 mph) due to the advanced aerodynamics which delivers an exceptionally low drag coefficient
of 0.212.
, Moravia
, today's Czech republic
, making it the third oldest still existing automobile manufacturer in the world. During the time the company, lead by Hans Ledwinka
employed many genius minds of automotive history, including Erich Übelacker
and consulted Paul Jaray
, who all took part in designing Tatra 77.
(LZ) where he gained experience with aerodynamic design of airships. He used his access to LZ's wind tunnel
s and subsequently he established streamlining principles for car design. In 1927 he founded a company specializing in development of streamlined car bodies and selling issuing licenses to major vehicle manufacturers including Tatra. Tatra was the only manufacturer to incorporate Jaray streamline principles into their series car production, starting with the Tatra 77.
Before designing the large luxurious T77, Jaray designed an aerodynamic body for the Tatra 57
, a mid-range model. This prototype was not further developed and failed to reach production. Instead, Jaray constructed two prototypes for a concept designated as the Tatra V570
, which more closely conformed to his aerodynamic streamlining principles, featuring a beetle-shaped body.
. 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 cars that would be fast, nearly silent, stable, economical and built to the most rigorous engineering standards as well as reflect modern aerodynamic research.
was responsible for the body. 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 145 km/h and amazed newspapermen with great handling and comfortable ride at speeds of about 100 km/h. 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 140 km/h 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 used T77a to take part in his sci-fi movie The Transatlantic Tunnel
.
, 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.
, mostly air-drag, which increases with the square
of speed. A car with a common body shape of the era needed a very powerful engine to reach higher speeds. The Tatra's new body shape was wind tunnel
tested. However, the new type of coach building required a change of the whole car's concept.
The requirement of a small front face area limited the car's height, which in turn required the use of a flat floor. That led to putting the engine in the rear of the car, directly above the driven axle. Subsequently there was no more need for a floor tunnel with a drive shaft and exhaust pipes, which contributed to weight loss. As the designers wanted to reduce the rolling resistance
, they did their best to produce an engine as light as possible - an air-cooled V8 with a crank case made from electron
. The transmission box
was made from electron as well and it was positioned in front of the rear axle and engine.
The rear position of the engine was favourable for the air cooling, while the oil cooler
, accumulator
and spare wheel were positioned in the front of the car. The frameless body was characterized by the central frame member, which was firmly welded to the floor panels and which covered the linkage to the brakes, gears, etc.
The front of the car has basically a rectangular cross section
and it is rounded at the front to the height of the floor. The front bumper covers the front rounded fenders, while the lower half of the lights is embedded in the front bonnet. The rear of the car has a continuous dropping form, and it's divided by a vertical fin, which starts at the rear end of the roof and ends almost at the rear end of the car. The rear wheels have aerodynamic covers. The door handles are embedded into the door panels, from which only the door hinges stood out, if also not by much. The car had no rear window, and rear visibility was fairly limited, and only possible trough slots on the sheet metal.
The first prototype of 1933 had a split windshield, while other prototypes had a one piece windshield or even one formd three separate pieces of glass, with one large central piece and two side parts angled sharply and flowing into the sides of the body.
The air was directed to the engine by rectangular ventilation inlets behind the side windows and it left the engine compartment through the rear exit vents. At the time Tatra registered numerous patents regarding the air flow to the rear engine compartment.
Later the rear part of the body was widened so that both the rear fenders and door hinges were embedded into the carrossery itself. The air now flowed through transversal inlets, which raised above the rear rounded roof. The trailing edge was hightend.
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 were seated on either side of the driver and the seats placed slightly back, as on the modern day McLaren F1
. All other T77's had the steering wheel on the right hand side as Czechoslovakia, like various other European countries, drove on the left before WWII.
The unique car pictured here is the two-door coupé prototype used by Erich Übelacker. This one also had the more powerful engine from the latter Tatra 87.
Hans Ledwinka
Hans Ledwinka was an Austrian automobile designer.- Youth :Ledwinka was born was born in Klosterneuburg , near Vienna, then part of the Austro-Hungarian Empire....
and Paul Jaray
Paul Jaray
Paul Jaray , 11 March 1889 Vienna–22 September 1974 St. Gallen, was an engineer and a pioneer of automotive streamlining.-Life:Jaray, of Hungarian-Jewish descent, was born in Vienna...
, the noted Zeppelin aerodynamic engineer. Launched in 1934, the Tatra 77 is a coach-built automobile constructed on a central tube-steel chassis
Backbone chassis
Backbone tube chassis is a type of an automobile construction chassis that is similar to the body-on-frame design. Instead of a two-dimensional ladder type structure, it consists of a strong tubular backbone that connects the front and rear suspension attachment areas...
and is powered by a 75 hp 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 later model T77A has a top speed of over 150 km/h (93.2 mph) due to the advanced aerodynamics which delivers an exceptionally low drag coefficient
Automobile drag coefficient
The drag coefficient is a common metric in automotive design pertaining to aerodynamic effects. As aerodynamic drag increases as the square of speed, a low value is preferable to a high one...
of 0.212.
History
The Tatra Company began manufacturing cars in 1897 in KopřivniceKoprivnice
Kopřivnice is a town in the Moravian-Silesian Region of the Czech Republic. It has cca 23,500 inhabitants.- History :In 1850, both of the former villages, Drnholec nad Lubinou and Větřkovice, became a part of the political district of Nový Jičín within the judicial district Příbor...
, Moravia
Moravia
Moravia is a historical region in Central Europe in the east of the Czech Republic, and one of the former Czech lands, together with Bohemia and Silesia. It takes its name from the Morava River which rises in the northwest of the region...
, today's Czech republic
Czech Republic
The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....
, making it the third oldest still existing automobile manufacturer in the world. During the time the company, lead by Hans Ledwinka
Hans Ledwinka
Hans Ledwinka was an Austrian automobile designer.- Youth :Ledwinka was born was born in Klosterneuburg , near Vienna, then part of the Austro-Hungarian Empire....
employed many genius minds of automotive history, including Erich Übelacker
Erich Übelacker
Erich Übelacker, 19 October 1899 – 30 June 1977, automobile engineerÜbelacker studied mechanical engineering at Prague Technical University and subsequently worked there as an assistant to Professor Rudolf Dörfl. During 1927-1939 he worked at Tatra Works in Kopřivnice in Moravia under the...
and consulted Paul Jaray
Paul Jaray
Paul Jaray , 11 March 1889 Vienna–22 September 1974 St. Gallen, was an engineer and a pioneer of automotive streamlining.-Life:Jaray, of Hungarian-Jewish descent, was born in Vienna...
, who all took part in designing Tatra 77.
Paul Jaray and Tatra V570
Paul Jaray first worked at Luftschiffbau ZeppelinLuftschiffbau Zeppelin
Luftschiffbau Zeppelin GmbH is a German company which, during the early 20th century, was a leader in the design and manufacture of rigid airships, specifically of the Zeppelin type. The company was founded by Count Ferdinand von Zeppelin...
(LZ) where he gained experience with aerodynamic design of airships. He used his access to LZ's wind tunnel
Wind tunnel
A wind tunnel is a research tool used in aerodynamic research to study the effects of air moving past solid objects.-Theory of operation:Wind tunnels were first proposed as a means of studying vehicles in free flight...
s and subsequently he established streamlining principles for car design. In 1927 he founded a company specializing in development of streamlined car bodies and selling issuing licenses to major vehicle manufacturers including Tatra. Tatra was the only manufacturer to incorporate Jaray streamline principles into their series car production, starting with the Tatra 77.
Before designing the large luxurious T77, Jaray designed an aerodynamic body for the Tatra 57
Tatra 57
Tatra 57 is an automobile launched by Tatra company Tatra 57 is an automobile launched by Tatra company Tatra 57 is an automobile launched by Tatra company (in Czech: Závody Tatra, official name: Závody Tatra akciová společnost or Ringhoffer - Tatra company, also later known as Tatra Kopřivnice, in...
, a mid-range model. This prototype was not further developed and failed to reach production. Instead, Jaray constructed two prototypes for a concept designated as the Tatra V570
Tatra V570
Tatra V570 was a prototype early 1930s car developed by a team led by Hans Ledwinka and Paul Jaray. The aim of the construction team was to develop cheap people's car with an aerodynamic body...
, which more closely conformed to his aerodynamic streamlining principles, featuring a 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 ultra-reliable tradition started by model Tatra 11Tatra 11
The Tatra T11 was the first Tatra model to use the unique combination of major components that are still in use on the trucks produced by Tatra to this day.-Origins:...
. 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 cars that would be fast, nearly 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 ÜbelackerErich Übelacker
Erich Übelacker, 19 October 1899 – 30 June 1977, automobile engineerÜbelacker studied mechanical engineering at Prague Technical University and subsequently worked there as an assistant to Professor Rudolf Dörfl. During 1927-1939 he worked at Tatra Works in Kopřivnice in Moravia under the...
was responsible for the body. The development was very secretive until the last moments of the official presentation of May 3, 1934 at Prague
Prague
Prague is the capital and largest city of the Czech Republic. Situated in the north-west of the country on the Vltava river, the city is home to about 1.3 million people, while its metropolitan area is estimated to have a population of over 2.3 million...
motorshow. The car was demonstrated on the road from Prague to Karlovy Vary
Karlovy Vary
Karlovy Vary is a spa city situated in western Bohemia, Czech Republic, on the confluence of the rivers Ohře and Teplá, approximately west of Prague . It is named after King of Bohemia and Holy Roman Emperor Charles IV, who founded the city in 1370...
, where it easily reached 145 km/h and amazed newspapermen with great handling and comfortable ride at speeds of about 100 km/h. The same year was the T77 presented at Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
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 140 km/h was doubted, as normally at the time a car to reach such a speed needed about twice as much horsepower. Director Maurice Elvey
Maurice Elvey
Maurice Elvey was the most prolific film director in British history. He directed nearly 200 films between 1913 and 1957. During the silent film era he directed as many as twenty films per year....
was so amazed by the looks of the car that he used T77a to take part in his sci-fi movie The Transatlantic Tunnel
The Tunnel (1935 film)
The Tunnel, also known as Transatlantic Tunnel in the United States, is a 1935 British science fiction film based on the 1913 novel Der Tunnel by Bernhard Kellermann, about the building of a transatlantic tunnel. It was directed by Maurice Elvey and stars Richard Dix, Leslie Banks, Madge Evans,...
.
-
- "It is a 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 maintained 145km/h, 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
- "It is a 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 maintained 145km/h, 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."
Notable owners
The Tatra 77 was the particular favourite of Tatra design engineer Erich ÜbelackerErich Übelacker
Erich Übelacker, 19 October 1899 – 30 June 1977, automobile engineerÜbelacker studied mechanical engineering at Prague Technical University and subsequently worked there as an assistant to Professor Rudolf Dörfl. During 1927-1939 he worked at Tatra Works in Kopřivnice in Moravia under the...
, 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
Barrandov Studios
Barrandov Studios is a famous set of film studios in Prague, Czech Republic. It is the largest film studio in the country and one of the largest in Europe.Several of the movies filmed there won Academy Awards...
who bought a T77 in 1935, Austrian car designer Edmund Rumpler
Edmund Rumpler
Edmund Rumpler was an Austrian automobile and aircraft designer.Born in Vienna, then Austro-Hungarian Empire , he worked mainly in Germany.Lyons 1988, p.73 An automotive engineer by training, he collaborated with Hans Ledwinka on the first Nesseldorf , the Präsident, in 1897.By age 30, in 1902, he...
, who designed the aerodynamic Rumpler Tropfenwagen in 1921, Edvard Beneš
Edvard Beneš
Edvard Beneš was a leader of the Czechoslovak independence movement, Minister of Foreign Affairs and the second President of Czechoslovakia. He was known to be a skilled diplomat.- Youth :...
, 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 approach to the conception of the new car: First of all it was the aim to reduce dragDrag (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...
, mostly air-drag, which increases with the square
Square number
In mathematics, a square number, sometimes also called a perfect square, is an integer that is the square of an integer; in other words, it is the product of some integer with itself...
of speed. A car with a common body shape of the era needed a very powerful engine to reach higher speeds. The Tatra's new body shape was wind tunnel
Wind tunnel
A wind tunnel is a research tool used in aerodynamic research to study the effects of air moving past solid objects.-Theory of operation:Wind tunnels were first proposed as a means of studying vehicles in free flight...
tested. However, the new type of coach building required a change of the whole car's concept.
The requirement of a small front face area limited the car's height, which in turn required the use of a flat floor. That led to putting the engine in the rear of the car, directly above the driven axle. Subsequently there was no more need for a floor tunnel with a drive shaft and exhaust pipes, which contributed to weight loss. As the designers wanted to reduce the rolling resistance
Rolling resistance
Rolling resistance, sometimes called rolling friction or rolling drag, is the resistance that occurs when a round object such as a ball or tire rolls on a flat surface, in steady velocity straight line motion. It is caused mainly by the deformation of the object, the deformation of the surface, or...
, they did their best to produce an engine as light as possible - an air-cooled V8 with a crank case made from electron
Elektron (alloy)
Elektron was a magnesium alloy developed in Germany during the First World War between 1914-18 as a substitute for aluminium alloy. Elektron is unusually light and has a specific gravity of about 1.8 compared with the 2.8 of aluminium alloy. Elektron was used to make incendiary bombs: the B-1E...
. The transmission box
Transmission (mechanics)
A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...
was made from electron as well and it was positioned in front of the rear axle and engine.
The rear position of the engine was favourable for the air cooling, while the oil cooler
Radiator (engine cooling)
Radiators are used for cooling internal combustion engines, mainly in automobiles but also in piston-engined aircraft, railway locomotives, motorcycles, stationary generating plant or any similar use of such an engine....
, accumulator
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...
and spare wheel were positioned in the front of the car. The frameless body was characterized by the central frame member, which was firmly welded to the floor panels and which covered the linkage to the brakes, gears, etc.
The front of the car has basically a rectangular cross section
Cross section (geometry)
In geometry, a cross-section is the intersection of a figure in 2-dimensional space with a line, or of a body in 3-dimensional space with a plane, etc...
and it is rounded at the front to the height of the floor. The front bumper covers the front rounded fenders, while the lower half of the lights is embedded in the front bonnet. The rear of the car has a continuous dropping form, and it's divided by a vertical fin, which starts at the rear end of the roof and ends almost at the rear end of the car. The rear wheels have aerodynamic covers. The door handles are embedded into the door panels, from which only the door hinges stood out, if also not by much. The car had no rear window, and rear visibility was fairly limited, and only possible trough slots on the sheet metal.
The first prototype of 1933 had a split windshield, while other prototypes had a one piece windshield or even one formd three separate pieces of glass, with one large central piece and two side parts angled sharply and flowing into the sides of the body.
The air was directed to the engine by rectangular ventilation inlets behind the side windows and it left the engine compartment through the rear exit vents. At the time Tatra registered numerous patents regarding the air flow to the rear engine compartment.
Later the rear part of the body was widened so that both the rear fenders and door hinges were embedded into the carrossery itself. The air now flowed through transversal inlets, which raised above the rear rounded roof. The trailing edge was hightend.
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 80 mm. This increased the output to 75 hp and the maximum speed to 150 km/h. 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 T77s and T77as 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. Some sources, though, claim that this is the coefficient of 1:5 model, not of the car itself.Versions
The Tatra 77 was a hand-built car with leather interior. Some cars had a glass partition between the front seats and the rear seats. A sliding roof was 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 were seated on either side of the driver and the seats placed slightly back, as on the modern day McLaren F1
McLaren F1
The McLaren F1 is a supercar designed and manufactured by McLaren Automotive. Originally a concept conceived by Gordon Murray, he convinced Ron Dennis to back the project and engaged Peter Stevens to design the exterior of the car...
. All other T77's had the steering wheel on the right hand side as Czechoslovakia, like various other European countries, drove on the left before WWII.
The unique car pictured here is the two-door coupé prototype used by Erich Übelacker. This one also had the more powerful engine from the latter Tatra 87.
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 87.See also
- Tatra (car)Tatra (car)Tatra is a vehicle manufacturer in Kopřivnice, Czech Republic. The company was founded in 1850 as Schustala & Company later renamed Nesselsdorfer Wagenbau-Fabriksgesellschaft, a wagon and carriage manufacturer, and in 1897 produced the first motor car in central Europe, the Präsident. In 1918, it...
- Rumpler Tropfenwagen - aerodynamic car from 1921, of which about 100 units were built
- Chrysler AirflowChrysler AirflowThe Chrysler Airflow is an automobile produced by the Chrysler Corporation from 1934-1937. The Airflow was the first full-size American production car to use streamlining as a basis for building a sleeker automobile, one less susceptible to air resistance...