[Propellerhead]

No Nonny the dive bombing requirement was not the only reason for a twin airscrew layout. It also needed high level speed to satisfy requirements for a Ural bomber.

When Heinkel's chief designer, Siegfried Gunter developed the He-177 "Grief" (Griffon) he was obliged to meet specifications for a bomber capable of reaching the Urals, with a 1,000kg (2,204 lb) bomb load. It also had to fly 5,000km (3,107 mi) with the bomb load at a speed not less than 500 km/h (311 mph) "at altitude".

RLM however suggested to heinkel as early as 18 November 1938 that he should also produce prototypes for a more conventional four engined layout as an insurance policy against failure of the DB 606 engine. This became the He-177H and later from May to August 1943 as the He-177B.

The He-177H later developed into the He-274. The He-274 however sported greater span wings and abandoned the He-177A undercarriage arrangement (like two petals retracting sideways to a rear retracting twin wheel bogie for He-274). When Hitler urgently required a Strategic bomber at a conference in Obersalzberg on 23 May 1943, the He-274 design was too different to be mass produced quickly on existing He-177A production lines so the He-177B design was developed into the He-277.

Hitler demanded a bomber which could bomb Britain day and night. The only way to achieve this was with very great altitude. the He-277 B-5 and B-6 were intended to overfly England at 49,200 feet, well beyond any interception. They were intended it appears to carry one very large 2.5 tonne bomb externally, outside the bomb bay, or 6 tonnes of small bombs internally.

The He-177A by comparison had ralatively low service ceiling and performance much like the Lancaster.