Picture an aircraft that does not sit on a runway but stands upright on its tail, nose pointed at the sky like a rocket. Around its waist spins a three-bladed wing, driven not by an engine in the fuselage but by ramjets screaming at the very tips of the blades. To take off, it simply rises straight up. To land, the pilot must fall backwards out of the sky and settle, blind, onto four little wheels beneath the tail.

This was the Focke-Wulf Triebflügel — one of the most bizarre flying machines ever seriously designed. Drawn up in Germany in 1944, it was meant to defend the Reich from a shrinking patch of ground. It never flew. Looking at it, you understand why.

A wing that was also a propeller

The Triebflügel’s defining idea was its rotor-wing: three long blades mounted on a ring around the mid-fuselage, free to spin around the aircraft’s body. At the tip of each blade sat a ramjet. Small rockets would spin the assembly up until the ramjets lit; from then on, the spinning blades acted as an enormous propeller, hauling the aircraft vertically off its tail. In forward flight, that same rotating wing generated the lift to keep it airborne.

It was elegant on paper and terrifying in practice. Ramjets are gluttons for fuel and deafeningly loud, and a rotor spun from its tips carries brutal stresses. But the biggest problem waited at the end of every mission.

The landing nobody wanted to make

Taking off vertically is one thing. Landing a tailsitter is another entirely. The Triebflügel’s pilot would have to bring the machine to a hover, then lower it tail-first onto a cruciform undercarriage — descending essentially backwards, unable to see the ground properly, balancing a spinning rotor at low speed. Even with modern computers, vertical tailsitter landings are hard. In 1944, by hand, with a novice pilot and a whirling ramjet rotor overhead, it bordered on suicidal.

A wonder-weapon that stayed on paper

The Triebflügel belonged to the last, desperate wave of German “wonder-weapon” designs — aircraft meant to launch from tiny, hidden sites without runways as Allied bombers pounded the Reich. It got as far as wind-tunnel models, tested reportedly to around Mach 0.9. Then the war ended, and the strangest interceptor of the age went straight into the history books without ever turning a rotor in anger.

It is easy to laugh at. But the Triebflügel also asked a question aviation is still wrestling with today: how do you build a fast combat aircraft that needs no runway at all? Eighty years later, with tailsitting drones and VTOL fighters back on the drawing board, the mad German idea does not look quite so mad.

Sources: Deutsches Museum; Luft’46 design histories; German wartime technical archives.