Back to the Drawing Board: Heinkel He 177 GreIf

David Porter on military history's doomed inventions.

The He 177 was the only German heavy bomber to enter Luftwaffe service in significant numbers, with over 1,100 completed by the time that production ended in August 1944.

The type originated with a requirement issued in 1936 for a strategic bomber carrying a bomb-load of at least 1,000kg over a range of 3,100 miles, with a speed of at least 311mph.

This was demanding enough, but, just after Heinkel’s design won the contract in 1937, the specification was amended to include a requirement for dive-bombing capability, which at the time offered far greater accuracy than conventional level bombing.

The dive-bombing requirement forced the adoption of a twin-engine layout, but this meant that each engine had to deliver at least 2,000hp in order to reach the specified performance, something that no German powerplant of the 1930s could achieve.

The solution was to couple two existing engines side by side to drive a single propeller. Although this was brilliant in theory, in practice it caused horrendous problems with overheating engines and engine fires when the prototype began flight trials in November 1939.

Frantic redesign efforts were made, but in 1942 the aircraft finally entered production still plagued with the same engine problems, which were only significantly reduced a year later, following further extensive modifications, which were incorporated in the improved He 177 A-5.

Fragility despite its size

Even this version needed careful handling – the British test pilot Captain Eric Brown, who flew one just after the war, commented that: ‘I was all too aware of the intelligence reports of He 177s breaking up in the air… it really was nail-biting to have to treat a giant like this immense Heinkel bomber as if it were made of glass… Somehow the He 177 always conveyed an impression of fragility despite its size.’

Nevertheless, the type was used effectively on the Eastern Front – notably in mid-1944, when formations of up to 90 aircraft made high-altitude raids against targets such as the key railway hub at Velikiye Luki. However, increasing fuel shortages forced the abandonment of such attacks before they could have any real effect.

The He 177 was withdrawn from operational service in August 1944, as the Luftwaffe was forced to concentrate its dwindling resources on the Emergency Fighter Programme.

Ironically, the solution to the type’s engine problems had been identified as early as November 1938, when Ernst Heinkel, who had always been concerned about the coupled engine layout, requested authorisation to develop a conventional four-engine version of the aircraft. The proposal was finally authorised in 1942, when the Luftwaffe finally admitted that the He 177 was simply too large to be a practical dive-bomber.

Although Heinkel immediately restarted design work on the new version, designated He 177 B, so much time had been wasted that prototypes were not ready for flight trials until December 1943. These impressed test pilots with their superb handling, but the type had not entered production when the development programme was cancelled in mid-1944.

Image: Wikimedia Commons.