These four designs were presented as a new aircraft family in mid 1967. The DC-10-3 was a three-engined aircraft for continental routes like coast-to coast and a little lighter and smaller compared to the DC-10-10. The engine power calculated for this aircraft was 3 x 32 000 lb (142,2 kN), also smaller than the one of the DC-10-10's CF6-6 engine. Different nose designs appeared, including one with an upper deck. However, the most interesting thing on this aircraft was the tail, which is shown on the right. Somehow, the aircraft looked like an oversized Caravelle.
The DC-10-4 was designed for the same missions and should have the same engines as the -3. It was a larger aircraft with four engines instead of three. The concept was similar to today's Airbus A330 and A340.
The DC-10-J3 was equipped with larger engines with a thrust of 47 000 lb (209,15 kN) for intercontinental routes. Here again, it was lighter and smaller than the future aircraft, in this case the DC-10-30 and -40.
At last, we have the DC-10-J2, which was a twin-engined aircraft comparable to the Airbus A310. This aircraft was also proposed to have the larger engines.
Further analysis forced Mc Donnell - Douglas to focus on three-engined designs. They were the best compromise between range, fuel consumption, cargo capacity, safey, noise and overseas market sale chances. Many so-called experts have the opinion, that the success of the DC-10 was limited due to the trijet design and prefer the twin-engine concept. However, it should be noted that not only the regulations for overwater twin-engined operations (later known as ETOPS) were a limit to the twinjet. At the time, when the DC-10 was designed, high-thurst engines to power a twinjet with continental range were not available. This did not change until the early 1980s when the 767 and the A310-300 appeared and limited also the sale success of the first Airbus, the A300. Finally, the DC-10-3 with a conventional nose was used as a base for further designs and emerged in the DC-10-A and -B.