ΔE 16.4, loose: different enough that you should pick on purpose. Ivory RLM05 is more saturated, warmer than Cockpit Color Nakajima.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Ivory RLM05 is more saturated, warmer than Cockpit Color Nakajima.
The same difference applies the other way round: Cockpit Color Nakajima is more muted, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Cockpit Color Nakajima on the colour wheel See Ivory RLM05 on the colour wheel
All matches: Cockpit Color Nakajima equivalents · Ivory RLM05 equivalents