In 1968 the RAAF made a valiant attempt to standardise the name of the yet-to-be-delivered F-111C. It didn't work! The only two names that actually stuck were not even contemplated in this 1968 edict. In service the aeroplane was known as the F One Eleven or more affectionately, The Pig. The designation itself is often presented incorrectly without a hyphen (F111) or with the hyphen in the wrong place (F1-11). The country that built the aircraft leaves no room for variation. The mission designator F (for Fighter) should be followed by a hyphen and the sequence number (111) with no spaces.

Source: RAAF News September 1968