Why is the tail of the MD-87 taller than the tail on the rest of the aircraft in the MD-80 series?
Even though the MD-87 is smaller than the other MD-80s, it requires a larger vertical tail plane. This is due to the shorter moment arm from the vertical tail to the center of mass which is a result of the shortened fuselage. This is compensated by increasing the height of the vertical stabilizer. The MD-87 is the only type in the MD-80 series of aircraft with the taller tail.