Comment by dingaling
2 days ago
The DC-10 was a rushed programme to avoid Douglas being frozen out of the 1970s widebody market by Lockheed and Boeing.
Similarly, the MD-11 was a cost-restricted update of the airframe to avoid McD being frozen out of the 1990s widebody market by Airbus and Boeing.
McD management wouldn't fund the more ambitious four-engined MD-12, so the trijet's fuselage was stretched and aerodynamic tweaks applied.
The MD-11 never met its performance targets and heralded the end of the Douglas commercial line. It was fairly quickly relegated from pax to cargo service where it has a good payload but little else to commend it.
I always thought that the third engine was thrown into the tail of the DC-10 when they learned of the L-1011. However, I think I first heard that from a retired Tristar pilot.
https://en.wikipedia.org/wiki/Lockheed_L-1011_TriStar
Trijets were mostly a thing to allow operations further away from diversion airports. Until the mid 80s twin engine jets had to stay less than an hour from diversion airports which meant that most stuff over water or remote routes had to be trijet or quad.
The MD-11 was late to that party, and by the time they started flying they were already allowing twins to go farther. Now the limit is all the way up to 370 minutes from the nearest airport for some twins, and most are capable of flying transatlantic.