Bristol Britannia

Nicknamed the Whispering Giant for how quiet its Proteus turboprops were from the ground. Icing trouble with those engines delayed it by years, and the jets arrived before it could establish itself. No type certificate for it is reachable — the FAA's regulatory system is closed to us and EASA never held the type — so this entry carries its history but none of the certified weights the rest of the library is built on.