However, the supply of QB-17s was dwindling in the late 1950s, and in any case the 1930s-designed B-17 could not realistically represent modern Soviet aircraft. This led to the refitting of two RB-47E Stratojets (53-4245, 53–4246) that were being phased out of the inventory to a QB-47E drone configuration. The QB-47s also carried electronic countermeasures gear and chaff dispensers in order to make for a more realistic target for the Bomarc during the tests. The Bomarcs were programmed to intentionally near-miss because the Stratojets were deemed too expensive to be intentionally destroyed in testing. However, one Stratojet drone did end up being shot down when an intended near-miss by a Bomarc turned into a hit.Baugher, Joe (2003), Boeing QB-47E StratojetB-47 serial number search
