On the occasion of the 90th anniversary of the introduction of the first aerodynamic Tatra car, the National Technical Museum restored the black Tatra 77a from 1937, originally owned by businessman Evžen Porák. The car, which is a national cultural monument, also received its own 3D scan and haptic model for the blind. These were created by experts of the Faculty of Mechanical Engineering and the BUT spin-off 3Deposition.
The historic Tatra 77a is part of a set of five NW and Tatra cars from the collection of the National Technical Museum and will be on display to the public in a new exhibition at the Centre for Building Heritage of the National Technical Museum in Plasy. "There is certainly no need to highlight the well-known qualities of this car, which has the reputation of being the first production car with an aerodynamic body. However, this product from Kopřivnice has certainly attracted attention abroad not only because of its speed and travel comfort but above all because of its conceptually designed shapes with low air resistance, which are still highly rated. I am therefore very pleased that the National Technical Museum has completed the demanding restoration of the rare Tatra 77a from 1937 from its collection on the occasion of the anniversary," said Karel Ksandr, Director General of the Museum.
To make it easier for visitors with visual impairments to imagine the historical car, the museum also wanted to make a miniature haptic model for the exhibit. Therefore, it approached the BUT spin-off company 3Desposition, which also includes experts from the Institute of Machine and Industrial Design of the Faculty of Mechanical Engineering. For the production of the 1:5 scale Tatra model, a digital template was needed, which was taken up by researcher Tomáš Koutecký. "The scanning consisted of two main parts: photogrammetry and laser 3D scanning. Because the object is large and the handheld laser 3D scanner itself is designed more for digitizing smaller parts, the photogrammetry method was used before the actual scanning, which records the positions of contrasting circular marks in space from the photos with an accuracy of up to hundredths of a millimetre. The scan itself is then mapped onto these marks," Koutecký described the process, adding that fifteen hundred contrast marks were placed on the Tatra before the measurement.
"The model obtained by scanning had to be smoothed and the holes left by contrast points in the scan had to be "fixed". The resulting scan is very detailed and consists of about thirty million small triangles connected into a single network. For the needs of 3D printing of the haptic model, this network was significantly reduced and the model was simplified," says Koutecký. This is the third time he and his colleagues have made a similarly large and interesting object, in the past they have already scanned a parabolic solar power plant and a racing tractor, for which experts from the Industrial Design Department designed a new fairing.
The haptic model of Tatra itself was created in the BUT’s spin-off company 3Deposition, using robotic 3D printing technology utilizing a D-FINE filament 3D print head developed in cooperation with BUT.
The Tatra haptic model was created in the BUT‘s spin-off company 3Deposition (photo: 3Deposition)
A car ahead of its time
The Tatra 77 is a legend not only in national history but also in the history of world motoring. Thanks to its aerodynamic shape, this vehicle was a true revelation when it was launched in the 1930s. Of the total number of 255 documented pieces produced, only about two dozen are known to this day.
The automobile Tatra 77a with serial number 35690, body number 7735 and engine number 201712 was purchased in 1937 by the Czech-German businessman Evžen Porák, the owner of the Vltavský mlýn paper mill in Loučovice in Šumava. In the 1950s and 1960s, the car changed hands several times, and in 1974 it became part of the collections of the National Technical Museum and was in a generally poor condition. The car waited for its resurrection in the museum depository for almost fifty years. The aim of the restoration made possible thanks to EU funding, was to restore the car to a historically faithful and aesthetically attractive condition while preserving its authenticity as much as possible. Due to its high documentation value, the car was not put into operation, and no repairs or replacement of parts were carried out on the mechanical parts, regardless of the degree of their operational wear.
The car will be on display at the museum branch in Plasy from 28 March 2024 in the new exhibition "Tatra 77a – From Miracle to Wreck and Back".
The text is partly based on a press release from the National Technical Museum.