B-36H-20-CF serial 51-5712 was modified to become the NB-36H flying test-bed for a small nuclear reactor which was under development as an aircraft power plant. The Aircraft Nuclear Program was cancelled before the power plant became operational but the NB-36H made 47 flights between September 1955 and March 1957 to investigate nuclear shielding.

The sole Convair NB-36H, fitted with a nuclear reactor.

NB-36H/X-6 от компании "Convair". Первый в мире самолет с ЯР на борту NB-36H (изначально XB-36H) проектировался по требованиям ВВС США от 1946 года. Стоимость программы - 1 млрд долларов. На фотографии - экипаж фирмы "Convair" у NB-36H.

Атомная летающая лаборатория NB-36H

The unique role of the NB-36H called for unique ground support vehicles - the tracked vehicle on the left was a heavily shielded crane for the emergency removal of the reactor and the tug on the right was also shielded.

By the mid-1950s the concept of nuclear-powered aircraft had been converted into hardware in the USA, the sole XB/NB-36H making its first flight with a nuclear reactor aboard on July 20, 1955. The aircraft completed 89 flying hours with the reactor operational, but only for shielding trials; the reactor was never used for motive power.

Convair NB-36H 51-5712 was referred to as the Nuclear Test Aircraft (NTA) and made its first flight on July 20, 1955, at Carswell Air Force Base in Texas, in the hands of test pilot Beryl Erickson. The comparatively small nuclear reactor fitted within it was used only to test radioactive shielding and powered no part of the aircraft. Here it thunders into the air with the crew capsule hatch in the up-and-locked position.

The NB-36H, with the distinctive radioactive warning symbol on the fin, during one of the 47 test flights it made during its successful test programme. The first of these with a fully functioning ASTR was made on September 17, 1955, and the last was completed in March 1957.

The NB-36H made a number of flights carrying a nuclear reactor to test shielding, but the planned X-6 follow-on, with a nuclear power plant, posed problems that proved insoluble.

THE MIGHTY ATOM. The new U.S.A.F. designation N (or Nuclear is applied for the first time - to a Convair B-36H-CF. More than 370 of these 230-ft. span giants have been built - no fewer than 154 of which are B/RB-36Hs. This extra-special flying test-bed houses the world's first airborne test reactor (designated ASTR) which has a "twin" in equal power - one megawatt - ground Test Reactor. Both TRs are currently supplying valuable information in connection with projected WS-125A bomber with which Convair at Fort Worth, Texas, is intimately concerned. The TR has the nominal capacity of 150 lb. s.t . - if it were part of a propulsion system. The B-36 was chosen because of its fuselage length, increased in this case by a new nose and revised pilots' compartment. The shielded canopy superficially resembles that of a Vickers Viscount. Position of the TR is marked by reference to the red-painted air scoops (one each side of the rear fuselage) . The scooped air serves the TR's heat exchangers. Special markings applied to the NB-36H. (U .S.A.F.: 51-5712) include red wingtips and jet pods; the official Atomic Energy organge-vaned radiation symbol on the fin, and distinctive blue nose and fuselage striping. First flight of the NB-36H (then XB-36H) was on 17th September 1955 with A. S. Witchell, Jnr., at the controls. A crew of five was carried on this occasion. Whenever the NB-36H is airborne a "guardian" Boeing B-50 Superfortress is in attendance. On board are ten para-technicians who would be dropped to take charge of operations should the "hot" NB-36H be force-landed anywhere except the prescribed bases.

Ядерная энергия. Ядерная реакция, способная генерировать огромную энергию из малого количества вещества, одно время рассматривалась в качестве средства обеспечения почти неограниченной дальности полета. Самолет Convair NB-36H летал с действующим реактором для проверки систем защиты, но так никогда и не питался от ядерной энергии. Полеты выполнялись с заводского аэродрома "Convair" в Форт-Уорте над безлюдными районами штатов Нью-Мексико и Техас. Буква "N" в обозначение NB-36H указывает на экспериментальный статус самолета, а не на наличие на его борту ЯР. Свой последний полет NB-36H выполнил 28 марта 1957 года. С учетом приобретенного опыта на фирме "Convair" велось проектирование атомного стратегического бомбардировщика WS-125A, но предпочтение получил самолет North American XB-70. На Х-6, прототипом которого являлся NB-36H, предполагалась установка ЯР General Electric Р-1. Все работы по "атомным" самолетам свернули в начале 1961 года.
The Convair NB-36H was the first aeroplane to fly with an operating atomic reactor aboard.

В воздухе - летающая лаборатория NB-36H, 1956г.

NB-36H в полете сопровождает самолет B-29.

The fully pressurised lead-lined crew capsule for the NB-36H weighed some 11 tons. Note the panels installed on the side of the capsule with connection ports for the various control, electrical and hydraulic systems.

В носовую часть NB-36H устанавливается защитная капсула для экипажа

The Aircraft Shield Test Reactor (ASTR) and crew capsule ranged in their approximate prospective positions within the NB-36H on test rigs before installation. Note the extensive security measures at bottom left...

Реактор ASTR, устанавливаемый на NB-36H

Two views of HTRE-3 - the third and final Heat Transfer Reactor Experiment test assembly - at the Idaho National Laboratory (INL). These images, from General Electric’s report, show the nuclear reactor on the upper level (with external shield in place LEFT), and the nozzles of the two X39-5 axial-flow turbojet engines protruding from the lower level. This test rig survives, and is on public display adjacent to the car park of the main INL Experimental Breeder Reactor site west of Idaho Falls, having been moved about 30 miles (48km) south from Test Area North, where the trials took place during 1958-60.

Кабина летчиков самолета NB-36H
A pair of rare photographs of the interior of the NB-36H’s capsule, including a view of the cockpit on the
left and the flight engineer’s station on the right. The capsule was so heavily insulated that the crew reported that
the combined racket of six R-4360 piston engines plus four J47 jets at full pelt was barely audible during take-off.

A model of the Aircraft Shield Test Reactor installation for the NB-36H. The unit, to be mounted in the massive bomber’s capacious aft bomb-bay, was built by Convair and weighed some 35,000lb (15,900kg). It was configured to be removed from the bomb-bay after each test flight for further ground testing and examination.

Convair constructed a large model of the proposed X-6 to demonstrate the various aspects of ground-handling that would be required. This front view of the model shows the bank of four J53 turbojets that would make up the P-1 powerplant, the reactor being given the designation R-1. Note the flattening of the fuselage as it fairs into the powerplant/reactor bay.

Модель летающей лаборатории X-6 с полноценной атомной силовой установкой

Another view of the model, looking forward from the rear fuselage. Note the staggered arrangement of the four J53s, in which the two inner engines are placed further forward than the outer pair. The X-6 would also have required a special pit to have been built for the installation and removal of the 14-ton P-1 nuclear powerplant.

As this photograph of a specially-designed handling robot shows, it was intended that all ground-based activities involving the X-6 would be dealt with remotely, as the potential radiation hazards were deemed to be significant. A proposal to use the jet-powered Convair YB-60 was also mooted, but rejected.

Nuclear-powered flight: step 1, the NB-36H

Nuclear-powered flight: step 2, the X-6