Originally Posted by
finncapt
Earlier in the program they quickly glanced over the fact that the MD11 has a smaller rear tail and fin assembly - a fact that I was not aware of.
The MD-11 has a smaller horizontal stabilizer than the DC-10.
AFAIK the fin/rudder is identical on both.
My general understanding is that when a stretched model of an aircraft is produced it quite often requires larger tail surfaces.
That doesn't sound intuitive. On a stretched aircraft, the tail control surfaces have a greater moment arm about the CofG, so the reverse ought to apply.
A good case in point was the shortened 747SP, which required a larger fin/rudder than the regular 747 because of its reduced length.