TATRA: The Best Red Car

 

Most Communist-made Autos are dull dishes – but look what’s cooking in Czechoslovakia!

 

By F. H. Baer (Auto Sport Review [USA], October 1953)

 

 

MOST people are pretty well aware that the Russian Revolution produced no revolution in automotive design. Russian cars up to the present have been only conventional, mostly copies of early capitalist models. But few persons on the sunny side of the Iron Curtain are aware that the Communists now are manufacturing one of the most revolutionary cars in the world—a rear-engined, air-cooled, frameless five-passenger sedan that is rugged, reliable and efficient.

          The car, of course, is the Tatraplan, and there isn't much doubt that it is the best car produced under Communist planning. But its virtues and its revolutionary features can't be credited to the Reds. Its design elements were worked out and put into production literally decades ago, long before the Communists took over in Czechoslovakia.

          When Tatra started out to build the first automobiles of Central Europe, Czechoslovakia was part of the Austro-Hungarian Empire. The factory at Kopřivnice was privately owned and operated, and the automobile was just emerging from infancy.           Only 56 years later, the Tatra Works, now a big factory, is operating in Czechoslovakia with a Communist government dictating progress and production, with the state owning and operating the enterprise. The Tatra automobile, in the meantime, has grown up, after having passed the stages of poverty (technically) and of luxury (high price) to become an economic necessity.

SINCE the first Tatra Sports car, a two-cylinder overhead-valve pancake type which attained a record speed of 71 mph during the fall of 1899, the Tatra has not only kept up to date in technical respects, but also has often achieved technical fame, as when introducing independent wheel suspension, four-wheel brakes (during 1914), its first OHV engines (during 1906). The revolutionary central tubular "backbone" frame in 1923, and the air-cooled engine during that same year. The first racing success was achieved Internationally In 1925, when a Tatra car with independent suspension of all wheels, backbone frame, and an air-cooled engine won the 1925 Targa Florio race in Sicily, regarded by many as Europe's toughest trial.

          During 1934, the Tatra Works again surprised the automotive world: a fully streamlined sedan was produced, with a V-8 air-cooled, overhead-camshaft engine powering the monobuilt body, the first car whose body's final form was determined in the wind-tunnel of a near-by airplane factory. It featured built-in front lights, with a center light in the front hood for better driving in mist and rain. The engine turned out 15 hp at 4000 rpm; top speed was raised to 98 mph—for a serial passenger car. In 1934, mind you—and at

modest fuel consumption which permitted an average of 24 miles per U.S. gallon.

          Tested in an Australian trip, the air-cooled engine proved its reliability in that hot climate, and some time later two Czech engineers, Hanzelka and Zikmund, completed a round-the-world trip with such V-8 powered stock sedans.

 

BACK in 1920 to 1933, the Tatra Works produced the little "12" model, with a two-cylinder air-cooled engine of 1000 cc piston displacement, a power-plant laid out for a peak production of 12 hp at 2500 rpm. The noisy engine soon earned the nickname "Sewing Machine" for this model (many of these models are still in daily operation, as are U.S.-built Model T and A Fords). Produced by the Nesselsdorf plant of the Tatra concern, these cars still look and perform well.

                      During World War II Tatras of the 57a series were built under German supervision for use in the German Wehrmacht.

                      During 1948, the year the present Communist government took over, the Tatra Works were nationalized. Plans were announced concerning construction and production of a new type of the Tatra rear-engine car. The Tatraplan.

                      Following the trend of the time, the Tatraplan engine was only half the piston displacement of the former V-8 model, which was produced from 1934 to

1948, (or 14 years without major technical changes). This was to permit the car's entering a more economical tax group (a very important detail in Europe), and to make the engine consume less fuel (for gasoline was then rationed, expensive, and of inferior quality) without sacrifice of too much in top speed.

                       Mainly responsible for the construction of the Tatraplan, as well as the former V-8 engine car and the series "12" model of 1923 was Austrian engineer, Dr. Ledwinka of Vienna. Gifted as a constructor of engines as well as an expert on car bodies. Dr. Ledwinka never was well-known internationally as was Dr. Porsche, a fact which does injustice to Ledwinka's noteworthy successes.

 

THE new Tatraplan should be credited with a series "first" and original developments. First of all: The engine is mounted in the rear of the car. It is air-cooled, and it is of the horizontal "pancake" [boxer] type. This arrangement is not, as many might believe, a copy of the German Volkswagen or the later Porsche or the Austrian Denzel Sports models. Rather it is a fact that all these cars have copied the Tatra "77" rear-engine design which was first built in 1934. The first air-cooled system was built by Tatra in 1923, as was the pancake type engine. Also to be remembered is the fact that Dr. Porsche participated in the construction of the model "87" Tatra, the improved V-8 model.

           The second element is the body: The fact that Tatra built its first "monobuilt" body 17 years ago (1937) and also built the first aerodynamically influenced body 19 years ago (1935) labels the Tatra engineers of these days as pioneers in that field. Studying the form of a drop of water in free fall, the engineers decided on the basic form of the body, leaving all detail modeling to extensive tests in wind tunnels. Actually this "water drop" method does not represent the most modern conception of body construction. The principle has been altered in actual construction to compromise with other factors (such as engine location, steering diagram, location and size of fenders, angle and size of windshield etc).

 

WITH Tatra the rear engine is a tradition. The engineers there claim that only a rear-mounted engine permits an ideal streamlining of the body, an aerodynamically valid form to reduce air resistance and increase top speed with simultaneous decrease in gasoline consumption. The engine, together with clutch, transmission, propeller shaft and differential, forms a solid unit, which is easily serviceable, easily exchangeable. The fact that all these aggregates are built in a solid unit permits a low mounting in the frame, thus aiding stability at high speed and while cornering, due to the low center of gravity.

           No gasoline, oil or exhaust fumes trouble the driver and the passengers. The noise of the rather loud engine (all air-cooled engines are louder than water-cooled units) is not detectable above a speed of 50 miles per hour.

           The absence of a long propeller shaft eliminates mechanical troubles in universal joints, otherwise caused by vibration after moderate mileage. There is no propeller shaft tunnel along the floor and thus more leg-room. The absence of a propeller shaft also permits a lowered floor, thus lowering the center of gravity for better stability. Also a flat-built floor streamlines the bottom of the car.

           Another plus for the rear-engine Tatraplan is the claim that the air used both for the fuel-air mixture and for-the cooling of the entire engine is forced by the car's forward movement through, air ducts formed by the rear engine hood. This high, dust free intake gives assurance that the air filters for the carburetors do not get clogged so soon. (The consumption of gasoline goes up steeply if the necessary amount of air is not available, due to clogged air filters.) It also aids in keeping the engine clean, avoiding dust particles covering the cooling fins around the cylinders' surface, which would necessarily lower the heat dissipation rate.

           The intensity of the air-cooling unit—an axial blower driven by a belt from the crankshaft pulley—is entirely dependent on the rpm of the engine. Driving in low gear over a high mountain (in the high rpm range) or at high speed over flat stretches (in the upper rpm range, too), the engine gets a precisely calculated amount of fresh air.

 

WHILE the heat range in a water-cooled engine extends from an average of 68 degrees Fahrenheit (outside air) to 212 degrees (boiling point), the heat range in an air-cooled engine is much wider. It varies from the local air temperature, (68 degrees) to the normal operating temperature of an explosion engine, which is 356 degrees. While the water-cooled power-plant thus has a range of 144 degrees, the air-cooled engines have such a range of 288 degrees, or double the range of heat variations (within safe limits).

           This is especially important in hot climates, where the outside air temperature may go up to 120 degrees, thus decreasing the heat range in water-cooled units to 112 degrees and in air-cooled power plants from 244 degrees.

           The condition of the crankshaft and the connecting rod bearings is kept at a good operating level by the oil, which is air-cooled in a special radiator mounted in front of the car, a system which combines correct setting of the cooling degree (by shutters in front of the radiator), and the long oil lines reaching from the rear-mounted engine to the front radiator and back. The oil supply in this engine, though larger in volume than in normal cars, has a longer life because of the constant cooling, and also on account of an oil filter (which is of the mechanical type), agitated by a linkage system every time the clutch pedal is depressed.

           The construction of the pancake-type engine—now successfully copied by the German Volkswagen, the Porsche, the Austrian Denzel, and the Porsche Gloeckler—permitted a flat engine compartment for better body construction. Also there was a wider base for the engine mounts (to reduce engine vibration', and a low level of mounting for better weight distribution and a low center of gravity. This type also permits low mounting without sacrificing the ground clearance of the oilpan.

           Returning to the second argument for the Tatraplan, the body construction: a car with a horsepower-to-weight ratio of 50.7 pounds per horsepower, in comparison to the USA's closest engine-sized car. Kaiser's Henry J., which has a ratio of 34.7 Ibs per hp, the Czech car certainly does not have an outstanding ratio.

           But Tatra's engineers purposely kept the engine small (for reasons of economy) and put most attention on the air-resisting factors of the body. These people came up with such a streamlined body that it makes up in lowered air-resistance what the Tatraplan lacks in weight-horsepower ratio.

 

THE rear-engine construction shortens the front section of the body, resulting in a relatively short hood which houses only the gasoline tank, one spare tire and a small piece of luggage, while permitting a very good vision to the front and the side of the road ahead—definitely a big safety factor.

The monobuilt body has been Tatra's ever since 1937. It has, however, stuck to the earlier invention of the backbone layout, a center rectangular beam with a fork for the engine mounting in the rear. Welded to this tough beam are the crossmembers and the engine floor. The front wheels are suspended from a center mount on the beam's front end.

           Welded to the flat floorplate is an all-steel outer body shell, with steel girders inside of this shell. The inside shell is welded to these girders, protecting the head-room and the roof of the car giving triple strength in this—still lightweight—construction.

           Compared with front-engine cars there is never any noise in this Tatra model. Also avoided is the nuisance squeak of from 12 to 30 screws which either shake loose, break or rust in conventional design cars.

           In case of accidents, the Tatra is not—as often believed of all rear-engine cars—more dangerous than cars having the engine to "protect" driver and passengers. (With an impact of the same magnitude the conventional car's front engine does not so much take the first shock as transmit the shock. Increasing the engine's bulk weight toward the passengers' compartment. This is far more dangerous and disastrous than a rear-engine adding to the momentum to a car in an accident). The relatively strong central beam can be damaged much less than any other frame system known.

           The front suspension is on the conventional side. Owing to the structure and shape of the central beam, the Tatra has a center spring base, the dual (upper and lower) transverse leaf springs being regulated in their action by long dual action telescopic shock absorbers. The rear wheels, suspended by torsion bars, are of the swing-axle type; the shock absorbers are diagonally-mounted dual-action telescopic types.

 

Tatraplan