ΔE 7.0, close: similar, with a visible difference side by side. Brown RLM26 is more saturated, warmer than Braunviolett RLM 81.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Brown RLM26 is more saturated, warmer than Braunviolett RLM 81.
The same difference applies the other way round: Braunviolett RLM 81 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 Braunviolett RLM 81 on the colour wheel See Brown RLM26 on the colour wheel
All matches: Braunviolett RLM 81 equivalents · Brown RLM26 equivalents