[Llarry]

Two more examples of the old Navy designation system:

A Marine Corps GV-1 (G=refueling, V=Lockheed) refueling two Marine A4Ds (A=attack, 4th model, D=Douglas). The GV-1 was redesignated KC-130F in 1962 and the A4D was redesignated A-4. The GV was the only aircraft to ever use the G = refueler designation.

A Navy ZPG-3W blimp used to carry early warning radar in 1960. In this case, two letter function Z=lighter-than-air plus P=patrol and manufacturer G = Goodyear. 3rd model of this blimp and modified for airborne early warning. The next upgraded model blimp from Goodyear would've been ZP2G but the blimps went away in 1962.