Then there was the nuclear version - thankfully never commissioned.
A big slab of lead behind the crew, and after their war mission they were supposed to land on a glacier runway, be pushed back into a hole and entombed forever....
https://en.m.wikipedia.org/wiki/Convair_NB-36H
http://www.megazone.org/ANP/atomair.shtml
"And that was that. Neither the United States, nor the Soviet Union, nor any other country was ever able to develop a true atomic-powered aircraft. But a nuclear plane of sorts did manage to fly This was the NB-36H test airplane, authorized along with the X-6 design back in 1951. Its original B-36H airframe had been extensively modified, most notably with a 12-ton shielded crew capsule in the nose, a 4-ton lead disc shield in the middle and a number of large air intake and exhaust holes to cool the reactor in the aft section. The reactor was a 1000-kilowatt design weighing 35,000 pounds and situated in a removable mounting in the aft bomb bay Its operation was observed from the crew capsule by closed circuit television. When the plane was not being flown, the reactor was kept in a specially prepared pit near the runway at Convair's Fort Worth, Texas, facility.
NB-36H flew with its radioactive cargo 47 times between 1955 and 1957, and, although it did not power the airplane, the reactor provided considerable data on the effects of radiation emitted during night. Flying alongside NB-36H on every one of its flights was a Boeing C-97 Stratocruiser transport carrying a platoon of armed Marines ready to parachute down and surround the test airplane in case it crashed. This certainly deserved hazardous duty pay. Pity the poor troops assigned to this outfit, jocularly dubbed the "glow-in-the-dark platoon." Fortunately there never was a crash, and the test plane was eventually decommissioned at Fort Worth in late 1957. After languishing as a hulk for many months, it was scrapped."
