from “Nuclear-powered aircraft” (“Применение атомных двигателей в авиации”), published in 1957, by G. Nesterenko, A. Sobolev, and Yu. Sushkov.
Fig. 61: Atomic convertiplane of the future in Antarctica
Fig. 57: Possible variant of nuclear aircraft with reactor shared between engines and full radiation protection.
(Kindly submitted by Mr Alexey Mahotkin - immense thanks.)