Under a 1952 USAF contract, Convair was given a contract to modify three B-36H to test the Bell GAM-63 Rascal rocket-powered air-to-surface guided missile. These aircraft were redesignated DB-36H, where the D stood for "Director".
The name "Rascal" was actually an acronym which stood for RAdar SCAnning Link, so named for the guidance system that was used during the missile's final dive on the target. The GAM-63 missile was powered by a Bell-designed liquid-fuelled rocket engine made up of three vertical in-line thrust chambers and developing a thrust of 4000 pounds. It had a launch weight of about 13,000 pounds and was 31 feet long with a body diameter of 4 feet. At a top speed of Mach 2.95, the missile could carry a 3000-pound nuclear warhead up to 100 miles. 11 other B-36s were scheduled to be modified as Rascal carriers under the designation DB-36H.
The serial numbers of the modified DB-36Hs were 50-1085, 51-5706, and 51-5719. The GAM-63 was carried semi-recessed underneath the fuselage.
However, the Air Force decided in 1955 that the B-47 and not the B-36 would carry the GAM-63, and most of the DB-36 modification contract was cancelled. I don't believe that any test launches of Rascal missiles ever took place from a DB-36H. The Rascal turned out to be a fairly accurate and effective missile, but the concept rapidly became obsolete in the face of new developments in the field of air-launched missiles. The Rascal program was cancelled on September 9, 1958.