North American B-45 derivative with turboprops
Even before the basic B-45 Tornado had flown, North American was already at work on a follow-up design that would be suitable for tactical missions. This would have done away with the Tornado’s pure jet propulsion in favor of new nacelles with a turboprop up front and a turbojet in the rear. Martin had done similar with its P4M Mercator (although the Mercator’s front engine was a piston) and Boeing and Martin would also investigate turboprop versions of their bomber designs. The B-45 (as a pure jet) was again considered for the tactical role in the early 1950s as the USAF looked for an interim replacement for the B-26 Invader in Korea, but the service opted to buy the B-57 Canberra instead.