Russia Military maps
 

for free on Android
Linky
Africa and Asia too.
Full version is £7.96
no connection

Interesting-
Max zoom 1cm= 750m
Off line map storage on micro SD
and more. Well worth a look
Best practice your Russian first!

The old Russian Military Maps are copyright free, and have been available on the web for free from various sites for quite some time. They are raster maps (like a photo) NOT vector maps (as used by most GPS/SatNav systems). I've quite a few Gb of them.

For OZiexplorer users there is a free android application that will use the oziexplorer data to present the map on the screen just like oziexplorer does on your PC. Of course I have all the oziexplorer calibration files for the raster maps (Russian or otherwise) I have (over 12Gb for Australia).

I've had a set of the maps for the areas I'm interested in for a number of years now and run them on Ozi Explorer on an old Windows PDA (that's how long I've had them!).

They looked detailed enough until I downloaded a couple for the areas where I live so I could make some sort of judgement about how good they'd be for areas I don't know. That's when they went into the "if all else fails it's better than guessing which way (but only just)" category. If they're free then have a look but you'll need some proper maps as well.