The RB-36D was a specialized photographic-reconnaissance version of the B-36D. It was outwardly identical to the standard B-36D, but carried a crew of 22 rather than 15, the additional crew members being needed to operate and maintain the photographic reconnaissance equipment that was carried. The forward bomb bay in the bomber was replaced by a pressurized manned compartment that was filled with fourteen cameras. This compartment included a small darkroom where a photo technician could develop the film. The second bomb bay contained up to 80 T86 photo flash bombs, while the third bay could carry an extra 3000 gallon droppable fuel tank. The fourth bomb bay carried ferret ECM equipment. The defensive armament of sixteen 20-mm cannon was retained. The extra fuel tanks increased the endurance to up to 50 hours.
The standard RB-36D carried up to 23 cameras, primarily K-17C, K-22A, K-38, and K-40 cameras. A special 240-foot focal length camera was tested on 44-92088, the aircraft being redesignated ERB-36D. The long focal length was achieved by using a two-mirror reflection system. The camera was supposedly capable of resolving a golf ball at an altitude of 40,000 feet. This camera is now with the Air Force Museum at Wright Patterson AFB.
Externally, the RB-36D was similar to the B-36D bomber bersion, but the RB-36D had many more antenna and had four large radomes--one forward of the nose landing gear and three more on the belly installed in the number 4 bomb bay.
The first RB-36D (44-92088) made its initial flight on December 18, 1949, only 6 months after the first B-36D had flown. It initially flew without the turbojets. The RB-36D actually preceded the B-36D into service with SAC by a couple of months, the 28th Strategic Reconnaissance Wing based at Rapid City AFB (later renamed Ellsworth AFB) in South Dakota receiving its first RB-36D on June 3, 1950.
A total of 24 RB-36Ds were built. The Air Force carried all of these 24 aircraft on their records as RB-36D, but 7 of these RB-36Ds initially appeared on Convair records as B-36Bs. All were delivered to the 28th Strategic Reconnaissance Group at Rapid City, South Dakota beginning in June of 1950. Due to severe materiel shortages, the new RB-36Ds did not become operationally ready until June of 1951. The 24th and last RB-36D was delivered in May of 1951.
In contrast to what is said in some B-36 books and articles, no aircraft originally built as a B-36B was converted to RB-36D. The confusion might be due to Convair line records showing 44-92088/92094 as starting construction as B models, even though they did not leave the factory that way.
Some RB-36Ds were modified to the Featherweight configuration, in which all but the tail guns were removed. In addition, most of the fire control avionics were removed. The crew was reduced from 22 to 19. These aircraft were redesignated as RB-36D-III. Modifications were carried out by Convair from February 1954 to November 1954.
44-92088/92094 Consolidated RB-36D-1-CF Peacemaker Originally ordered as B-36B. 49-2686 Convair RB-36D-5-CF Peacemaker 49-2687/2693 Convair RB-36D-10-CF Peacemaker 2687 modified to GRB-36D. 2692 modified to GRB-36D. 49-2694/2697 Convair RB-36D-15-CF Peacemaker 2694 modified to GRB-36D 2695 modified to GRB-36D 2696 modified to GRB-36D 49-2698/2702 Convair RB-36D-20-CF Peacemaker 2701 modified to GRB-36D 2702 modified to GRB-36D