He177 Tail Guns

The Heinkel He 177 Greif (Griffin) was a large, long-range heavy bomber flown by the Luftwaffe during World War II. The He 177 was the only operational long-range heavy bomber available to the Luftwaffe during the war years that had a payload/range capability similar to the four-engined heavy bombers flown by the USAAF and RAF in the European theatre; it had higher cruising and maximum speeds.

Designed to a 1936 requirement known as Bomber A, the aircraft was originally intended to be a purely strategic bomber intended to support a long-term bombing campaign against Soviet industry in the Urals. In spite of its large, 30 metres (98 ft) wingspan, the design was limited to two engines. During the design, Luftwaffe doctrine came to stress the use of moderate-angle dive bombing, or "glide bombing", to improve accuracy. Applying the changes needed for this type of attack to such a large aircraft was unrealistic.

To deliver the power required from only two engines on an aircraft this large, engines of at least 2,000 horsepower (1,500 kW) were needed. Such designs were not well established and the DB 606 "power system" engine, combined with the cooling and maintenance problems caused by the tight nacelles, caused the engines to be infamous for catching fire in flight. Early models gained the nicknames Reichsfeuerzeug (Reich's lighter or Flaming Coffin) from Luftwaffe aircrew.

The type matured into a usable design too late in the war to play an important role. It was built and used in some numbers, especially on the Eastern Front where its range was particularly useful. It is notable for its use in mass raids on Velikiye Luki in 1944, one of the late-war heavy bombing efforts by the Luftwaffe. It saw considerably less use on the Western Front, although it played a role during Operation Steinbock (baby blitz), against the UK in 1944.
https://en.wikipedia.org/wiki/Heinkel_He_177