One or the other. Probably your way, Stargazer. I'm familiar enough with Russian to get some things right, but this is a puzzle. I was thinking that Russians like to do without ambiguous, unaccented vowels. Like the name "Alexander" in Russian dispenses with the last "e" between the "d" and the "r"--АЛЭКЗАНДР, and so many two-syllable words will have their accents on the second syllable. I didn't want Grew-mán, so figured that the Russkies would just shorten it so the accent falls on the first grunt.
I suppose there is SOMEONE out there who might have access to Russian aviation literature. When I googled some stuff, the Russian text just broke into English to name the plane, then went back into Russian to describe it.