Two B-47Es (51-5219, 51-5220) were completed in January 1954 as YDB-47E for service tests with the Bell GAM-63 Rascal air to surface missile. The missile was suspended from the starboard side of the fuselage behind the wing. After the missile was released, it was guided to the target by radio control from the parent YDB-47E. These modifications resulted in a model number change to 450-167-50.
Two additional B-47Es (53-2345, 53-2346) were converted to Rascal carriers under the designation DB-47E. They were essentially similar to the YDB-47E except they carried the Boeing designation of Model 450-172-52. These later served as drone directors with the 3205th Drone Group at Eglin AFB in Florida.
The Rascal (which was originally designated as the XB-63) was an air-to-surface guided missile equipped with a nuclear warhead. Rascal development began in April 1946, and it was intended as a standoff weapon to be launched from bombers as far away as 100 miles from the target, thus reducing the bomber crew's exposure to enemy defenses. The first Rascal test launch did not take place until October of 1953. Plans to produce a large number of DB-47Es were abandoned when the GAM-63 Rascal program was cancelled in late 1958. The Boeing AGM-28 Hound Dog missile program replaced the Rascal program.