For a tethered device such as an air observation platform, it is possible to run the power up the tether. In an attempt to create a more practical solution than the clumsy balloons then in use, the Austro-Hungarian Petróczy-Kármán-Žurovec PKZ-1 electric-powered helicopter was flown in 1917. It had a specially-designed continuous-rated electric motor made by Austro-Daimler and received its power up a cable from a ground-based DC generator. However electric motors were not yet powerful enough for such applications and the motor burned out after only a few flights.