Boeing 747-300 TriJet concept

During the 1970’s Boeing wanted to better compete with the DC-10 and L1011. The Boeing 747SP was too costly to directly compete, so for a short while, Boeing looked at creating a 747 with three jets instead of the standard four. The design has two jets on the wing and one on the tail in an “S” configuration, much like the L1011. The concept was scrapped since it would take too much time, money, and a new wing design.