http://www.dogswar.ru/oryjeinaia-ekzotika/aviaciia/4273-proekt-bombardirovsh.html
"Simultaneously with the construction and testing of the Il-54 experimental bomber, Ilyushin OKB conducted research to determine the configuration of the new supersonic tactical bomber that received the IL-56 index. These works were started in connection with the decision of the Central Committee of the CPSU and the government of March 28, 1956. In particular, it was said that OKB Ilyushin and the Ministry of Aviation Industry submitted in June 1956 proposals for a deadline for the construction of a prototype and the beginning of flight tests.
The main technical requirements included the maximum speed of the machine 1,7-1,9M, the normal bomb load in 2000 kg and the range of 2200 km. The ceiling was supposed to be within 14000-15000 m, and the take-off weight - 23000-24000 kg. The proposals for the power plant included a single-engine configuration with an AL-7F engine and a two-engine configuration with the then-designed Mikulin AM-11 engines with an afterburner.
As a result, the designers chose a twin-engine configuration. IL-56 was a two-seater high-wing with low-lying horizontal tail and a bicycle-type chassis. Semicircular air intakes with a moving central body in the form of a half-cone were placed on top of the fuselage at the junction with the wing. The wing sweep angle was 45 ° and 55 ° in various variants. Experiments with the models were carried out in the wind tunnel of TsAGI in 1955 and 1956. But in early 1956 work on this project was stopped and efforts were concentrated on the creation of a heavy cruise missile."
Another information.
https://biography.wikireading.ru/98234
http://raigap.livejournal.com/41160.html
I think these two side drawings shows single engine type Il-56 and twin engine type Il-56.
But I feel these shapes are little strange, especially air intake position.???