05 January 2010
During the development of the hydrogen bomb there were concerns by the USAF that the delivery aircraft wouldn't be able to successfully exit the target area after dropping the weapon. As the development of the Atlas ICBM was still years away, Project Brass Ring was initiated in 1950 to create an unmanned version of the Boeing B-47 Stratojet to carry the H-bomb which would be designated MB-47 which in turn would be controlled by a manned Stratojet designated DB-47.
North American Aviation developed a sophisticated navigation and flight control system for the MB-47- but given the Air Force's requirements that the system be fully automatic, jam-resistant, and be accurate, it pushed the technology of the day and by 1952 it had to be cancelled due to cost overruns. The USAF then turned to Sperry Gyroscope to pick up where North American left off and it eventually cost a then-hefty sum of $2.3 million to complete. The MB-47 made its first flight on 7 May 1952 and by that summer both the MB-47 and the DB-47 controller had made several test flights with encouraging results. However, the cost of Project Brass Ring had nearly doubled from $4.9 million to just over $10 million.
By this point in the program SAC had determined that the Convair B-36 Peacemaker would be able to deliver the first production H-bombs if they were equipped with a parachute-retarding lay-down system. Furthermore, gaining permission from NATO members to forward deploy Stratojets in the UK, Spain, and French Morrocco made Project Brass Ring unnecessary and the program was terminated in April 1953.
Source: Boeing's B-47 Stratojet by Alwyn T. Lloyd. Speciality Press, 2005, p206-207