At the Heinkel aircraft company’s Marienehe airfield near Rostock, Germany, on the morning of August 27, 1939, witnesses heard a strange whistling howl. Rising from the runway was an aircraft with no propeller, its nose open to the air, its exhaust pipe thrusting from the tailcone. Flugkapitän Erich Warsitz advanced the throttle of the Heinkel He 178, and the world’s first turbojet aircraft clawed forward. The engine—designed by Dr. Hans Joachim Pabst von Ohain and funded by Ernst Heinkel—was the HeS 3, a centrifugal-flow turbojet burning gasoline. After a brief hop three days earlier, the He 178 made its true maiden flight, lasting six minutes and covering a short circuit of the field. Warsitz reported that the machine moved slowly at first, then gathered speed, its rudder and flaps working almost normally while the turbine howled. Only the landing was tricky: the undercarriage failed to retract, and he side-slipped down to a wonderful touchdown just short of the Warnow River. The He 178 reached speeds of 598 km/h (372 mph), but its ten-minute endurance and small size left Nazi officials Ernst Udet and Erhard Milch unimpressed. Yet the flight had opened the jet age. When Britain’s Gloster E.28/39 flew under Whittle power in May 1941, the He 178 had already been aloft for nearly two years, proving that the propeller’s reign was ending.