Slavoljub Penkala


…The airplane was slowly swaying on the turf. Suddenly the engine roared to full power. The mechanics are holding the fuselage down. The wheel chocks are still under the wheels. Another engine test. Penkala increases throttle, the engine screams and the whole aircraft is shivering like a giant butterfly. The spectators plugged their ears. The last hand signal. Chocks away, mechanics release the fuselage. The airplane slowly taxies down the field, right next to embankment. The group of spectators on the embankment spreaded themselves quickly. Behind the aeroplane everything is blown in the air, including grass. Penkala positions the aeroplane , correcty, downside of a breeze. And now, full throttle. And the aeroplane moves ever faster down the field. Two or three jumps, but no take off. Another jump, and then a sigh from all present: Aaah! Penkala's aeroplane is flying, gaining height. It's allready up two, three metres. Rising another five, six, seven...ten metres in the air. Faster and faster it gains distance from the crowd, already a hundred metres away, flying steadily. The sun reflects from the shiny propeller disc. Penkala can't be seen, only a dark shape in the middle of aeroplane, beneath the wing. The crowd chased the plane. The air is full of caps and hats, everyone is exalted. 


S. Penkala i D. Novak with a second version of Leptir (Butterfly), as the aeroplane was nicknamed 

- Penkala is flying ! People, he can't be stopped ! The aeroplane is already near the embankment. - If only he could land wihtout ramming the embankment! - a voice from the crowd. But the plane is slowly descending, lower and lower. It touched the ground. Rolls a few metres and, now, it has stopped...

Penkala, Slavoljub Eduard, (Liptovsky sv. Mikulaš, 20. IV 1871 - Zagreb, 5. II 1922), engineer of chemistry, inventor of first mechanical pen (propelling - sling -pen), the "penkala" , fountain-pen (1906), constructor of the first two-seat aeroplane in Croatia (1909).

S. Penkala at controls of the Leptir

With this aeroplane flew also the first Croatian graduated pilot Dragutin Novak (1910). Penkala also invented the first hotwater bottle, vacuum-flask, detergenta, rotating toothbrush, pen clip-holder, vhich enabled pens to be secured in the pocket, railway car brkes, anodic batteries, the ksilolite preparation against parasites in railway sleepers, the flow-meter device for liquids, pressure gauge, dynamometer, ebonite plastic mass used for manufacture of gramophone records, special microphones and listening devices, tens of chemical preparations and mechanical devices. He patented over 80 inventions. He calculated turbines and propellers for helicopters. While studying the airflow over an wingfoil, he found a new lift source, and in 1908 made his first design of a hoovercraft. He graduated chemistry in Dresden in 1898. He was "Higher Banski measures superviser" ( Ban was the elected ruler of Croatia since the death of the last ing of Croatian origin in 1097). His amateur aeroplane workshop was in his vestibule, at No. 17 King Tomislav Square (then Emperor Franz Jozef Square, later (1904) he built the first hangar in Crnomereca, at then military practicing field, ad so opened the first airfield in Croatia. He died in Zagreb from pneumonia, at his creative peak, in 51st year of his life.

Pilots and mechanics with first version of the Leptir 

With those words the late profesor dr. ing. Boris Puhlovski described in dhis book "Penkala leti (Život i rad izumitelja)" ( "Penkala flies -the life and work of an inventor) the first flight of Penka's aeroplane, june 23rd 1910. 

Penkala's aeroplane, nicknamed Leptir (Butterfly) was 11 metres long, had a 11 metres wingspan, weight of 330 kg, had a 25hp engine and a maximum speed of 57kph.. 

Text and photographs from the B. Puhlovski book "Penkala leti (Život i rad izumitelja)" ( "Penkala flies -the life and work of an inventor) was prepared by : 


Miljenko Frčko