Heinkel entered the field of jet propulsion through his acquaintance with the physicist Robert Pohl of the University of Gottingen. Professor Pohl had a graduate student, Hans von Ohain, who had invented a jet engine. It didn't work very well, but Pohl recommended Ohain to Heinkel, who hired him. With support from Heinkel, Ohain built a jet that ran successfully in March 1937. Two years later, he had one with twice as much thrust. Heinkel installed it in the He 178, which flew in August 1939. It was the world's first jet plane.