When the ‘effects’ B-36D conducted the first test (the Mike shot on Oct. 31, 1952, using a Mk 5 thermonuclear device detonated at Eniwetok atoll in the Pacific), it was almost caught in the mushroom cloud following the detonation.
The tale of some of the B-36 bombers used for Peacemaker’s operational procedures for nuclear strikes established via realistic tests with actual bombs.
Conceived during 1941 in case Germany occupied Britain, when US bombers would then have insufficient range to retaliate, the B-36 was to be primarily a ‘10,000-mile bomber’ with heavy defensive armament and a performance that would prevent interception by fighters.
Although rapid developments in jet engine and high-speed airframe technology quickly made it obsolescent, the B-36 took part in many important nuclear test programmes. The aircraft also provided the US nuclear deterrent until the faster B-52 became available in 1955.
As explained by Peter E. Davies in his book B-36 ‘Peacemaker’ Units of the Cold War, operational procedures for nuclear strikes conducted by B-36s could only be established via realistic tests with actual bombs. The US conducted a series of atmospheric tests involving high-flying B-36s between 1952 and 1956, the ‘Peacemakers’ performing as bombers, atmospheric sampling platforms and photographic aircraft. The sampling (or ‘effects’) missions also collected radioactive material from nuclear tests by the Soviet Union and Britain.
The first such event, codenamed Operation Ivy, took place in August 1952 and required a full-scale rehearsal called Operation Texas, staged from Bergstrom AFB, Texas. The latter involved 39 aircraft, including two B-36H bombers and a B-36D sampling and observation aircraft. A nuclear ‘training shape’ was dropped in the Gulf of Mexico, and the conditions for a real 500 kiloton Mk 18 bomb were simulated to ascertain the optimum speeds, drop altitudes and escape turns for the B-36. At the conclusion of the simulation it was still not clear whether the bombers would be able to escape the blast without being incinerated by radiation.
When the ‘effects’ B-36D during the actual Ivy flights conducted the first test (the Mike shot on Oct. 31, 1952, using a Mk 5 thermonuclear device codenamed ‘Sausage’ detonated at Eniwetok atoll in the Pacific), it was almost caught in the mushroom cloud following the detonation, despite the aircraft being at 40,000 ft and 15 miles from the explosion. The bomber experienced very high temperatures and bending forces on its tail area. SAC had refused requests for a drogue parachute to be fitted to the bomb to slow its descent.
The second test, codenamed King, involved a Mk 18 weapon. Again, a rehearsal was conducted by an unmarked B-36H dropping a dummy Mk 18 near Eniwetok on Nov. 8, 1952. One week later, the real Mk 18 was dropped from 40,000 ft, causing an apocalyptic 500 kiloton explosion at the end of its 56-second fall. The B-36H completed its break-away turn, but still received blast damage and loads on its tail which approached the structural limits. This first series of tests brought about two B-36 modifications – the application of heat-reflective white paint on the undersides of the bomber and the installation of detachable aluminised asbestos shields inside the cockpit canopy to offer some measure of flash protection for the crew.
Carswell’s 7th BW provided 12 B-36s for support of the oddly named Operations Upshot-Knothole and Tumbler-Snapper tests at the Nevada test site for nuclear weapons. They included dropping a lower-yield Mk 7 tactical bomb from a B-36 in order to help establish safe drop altitudes and measure shockwave stresses on the bomber’s structure. The tests were followed in 1954 by Operation Castle, which involved several types of bombers including a Featherweight B-36, an RB-36 and the Ivy B-36D ‘effects’ aircraft.
The ‘effects’ B-36D-5 49-2653, commanded by Maj Frederick Bachmann of the 436th BS, was subjected to blast loads at altitudes up to 50,000 ft that reached its structural limits and damaged the bomb-bay, landing gear doors, radome and scanner blisters and the undersides of the engine nacelles. Considerable damage resulted from the scorching of the unpainted areas of the lower surfaces, some of which were subjected to temperatures of 322°F. Much of the protective white paint was stripped away, and gun turrets, propeller spinners and the crew communication tunnel were among many damaged components.
Upon its return to Carswell, the aircraft was found to be so radioactive that it was parked well away from other aircraft on base for a year to ‘cool off’. When 49-2653 could finally be inspected in 1955, the airframe damage it had suffered was considered terminal and the bomber was scrapped. Other B-36s used in the tests were eventually decontaminated up to a year after their sampling flights.
B-36 ‘Peacemaker’ Units of the Cold War is published by Osprey Publishing and is available to order here.
Photo credit: Jack Fellows illustration via Weapons and Warfare and U.S. Air Force
When I was Staff Physicist at the Air Force Institute of Technology, one of the technicians was on that B36 during one of the tests. He said first the H-bomb went off and there was a flash so powerful that the thermal insulation across from the entry door lit on fire from the flash that came through the window. He moved to extinguish the and then the shock wave form the bomb hit and popped open the bomb bay doors and the large turbulence, though short lived set everything and everyone not trapped in bouncing. Yes he did get the fire extinguished.