Persu focused much of his career on researching the most adequate shape for a car to achieve the best drag coefficient. During his research, Persu established that this shape was that of a water droplet falling to the ground (drag coefficient of 0.04). This meant that for a car to be able to beat the air resistance it had to come close to both the shape of the droplet and its drag coefficient.
THE PERSU STREAMLINER
In 1922, Persu files a patent application for the vehicle in Germany, and receives it in 1924. The car, oddly shaped, had a drag coefficient of only 0.22 (for comparison, the 1996 GM EV1 has a drag coefficient of 3.95, while the 2006 Hummer H2 barely reaches 26.32; the average drag coefficient today is about 0.32).
The car was built in Germany by Persu, with the help of several local companies. Because of the small distance between the rear wheels, the engineer dropped the differential for good. As an engine, he chose a 1.4l four cylinder A-G f Automobilbau Berlin unit which developed 20 ps, paired to an Automobilbau transmission.
To prove the car is worth the time and money spent, Persu drove it from Germany to Romania, traveling with it over the following years a total distance of about 120.000 km (74,564 miles). He managed to achieve, at times, speeds of up to 80 km/h (50 mph). The lack of a differential made the car an ideal one when it came to turning at high speeds, allowing for the operation to be done even at 60 km/h (37 mph).
Despite his best efforts, however, Persu did not manage to make his idea catch. Several car manufacturers, including General Motors and Ford, have expressed their interest in purchasing the rights to manufacture the car. Because none of them promised to actually build the model, Persu did not sell the patent to anyone.
Soon, the Persu Streamliner slipped from public attention. Currently residing at the Romanian Dimitrie Leonida Technical Museum, the car is in a poor condition, with the body eaten away by the years and with a nonfunctional engine.
THE RUMPLER-TROPFEN AUTOSeparately from Persu, and strangely at about the exactly same time, in 1921, a German inventor by the name of Edmund Rumpler created what he called the Tropfen Auto, the tear drop car. As you might have guessed, his design was also based on the one of a water droplet, but unlike Persu's, it had a drag coefficient of 0.27.
Whereas Persu's vehicle looks like a droplet regardless of the point of view, the German version resembles a droplet when looked at from above. This gave it enough of a strange look to make the German manufacturer Benz try and sell it, and the public a great reason to reject it. Some 100 such vehicles were built, with a few of them even staring in Fritz Lang's 1827 science fiction movie Metropolis.
PERSU V3 HYBIRD
For the record, it is unclear at this point whether the name of the company has anything to do with the creator of the Persu Streamliner. Design wise, the V3 will probably be as aerodynamic as it gets, but this, amazingly, is not what will make the model special. V3's strong point will be the fact that the vehicle is, in fact, the first crossbreed between a car and a motorcycle.