tchman
the DC10 series had a larger elevator/empanage that was not anti iced.
the MD11 has a smaller empanage and is anti/deiced.
The therory was even with ice the bigger tail was adequate with an ice build up.
In ten years of flying DC10-30, I only ever had severe airframe icing, and would you believe it: it was on my first Command flight on a 10
The 10-30 was one of the best airframes I ever flew and I was lucky because I had 10 years on the " Big Cherokee"