The Heinkel He 277 was a four-engine, long-range heavy bomber design, originating as a derivative of the He 177, intended for production and use by the German Luftwaffe during World War II. The main difference was in its engines. While the He 177 used four engines in two coupled pairs which proved troublesome, the He 277 was intended to use four unitized BMW 801E 14-cylinder radial engines, in single nacelle installations.
The design was never produced and no prototype airframe was completed. The deteriorating condition of the German aviation industry late in the war and the competition from other long-range bomber designs from other firms, led to the design being cancelled.
Although not intended for it at first, the He 277 design became Heinkel's entry in the Amerikabomber programme for a long range bomber that could reach North America.
Designation
For many years after the war, a substantial number of aviation history books and magazine articles stated that Reichsmarschall Hermann Göring, early in World War II, was becoming so frustrated by the 177A's problems with its twin DB 606 "coupled" powerplants, that he forbade Ernst Heinkel from doing any work on a four-engined version of the 177 airframe, or even mentioning a new "He 277" design with four separate engines – by one account, in the late autumn of 1941 – until Heinkel brought the disagreement directly to Adolf Hitler, who supposedly not only approved of calling the new version of the 177 the "He 277", but overruled Göring's prohibition on working on the design (which Heinkel referred to as "He 177B" as a "cover designation" to hide its existence from Göring, and the RLM.)
Statements by Göring in August 1942 in response to Oberst Edgar Petersen's reports - in his capacity as the Kommandeur der Erprobungstellen ("commander of all Luftwaffe test stations"), at Erprobungsstelle Rechlin - on solving the serious problems with the original Heinkel He 177A's powerplants, seem to directly contradict elements of that narrative. ,The statements seem to show that Göring thought that the He 177A actually had four separate engines, and in late August 1942 Göring derisively labeled the He 177A's coupled engine arrangements, the DB 606 and DB 610 "power systems", as monstrous zusammengeschweißte Motoren, ("welded-together engines",) He was anxious to see a four-engined version of the bomber developed and in production. The earliest-dated initiative to be undertaken by Ernst Heinkel himself to trial a true "four-engined" design format for the original He 177 dated back to 17 November 1938, before the construction of the He 177 V3 and V4 prototype airframes had even been started, when Heinkel had personally asked the RLM to set aside the He 177 V3 and V4 airframes for a trial installation of four separate unitized Junkers Jumo 211 powerplants to overcome the concerns that the RLM Technischen-Amt technical department's director Ernst Udet and Heinkel had expressed about the RLM's specific dive-bombing priority for the He 177A, but was turned down for the trial fitment.
Facts that could have fostered the origin of the post-war aviation book storyline about the "He 177B"/He 277" controversy were that the RLM, in listing the He 177 development projects that they approved of the Heinkel firm doing work on as of February 1943 — six months after Göring's recorded engine complaint statements, and 18 months after the first-ever consideration by the RLM for any He 177 proposed variant to have four "individual" powerplants, as the paper-only "He 177H" high-altitude predecessor to the later He 274 in October 1941, only included the He 177 A-5 heavy bomber, A-6 high-altitude bomber, A-7 long-range version, and the "He 277" itself, defining the February 1943 date as the earliest reliable date of any official German government mention of such an "He 277"-designated aircraft, as this date also indicates the time by which the RLM had issued the Heinkel firm the 8-277 airframe design number for the project. The RLM was also expecting, during the late spring of 1943 — about one year after the Amerikabomber proposal first arrived in Göring's offices — that three He 277 V-series prototype aircraft, and construction of ten pre-production He 277A-0 series service test machines would come from Heinkel's Schwechat southern plant complex in Austria.