The Pe-8

I dont have any information that i could post, but i remember reading somewhere, or i think i remember correctly, that the initial raids were very succesful, as in the bombs were dropped on the city, with few losses. However as the raids increased in frequency, the losses started to mount, split between fighters and AA and AAA, though i think the anit-aircraft guns got more kills than the fighters, the skies over berlin controlled by the allies.

 

I believe this link should contain a good enough story.

http://www.geocities.com/Pentagon/Bunker/3351/campaigns/russrd.html

It's got just about everything about the Soviet raids on Berlin. The main problem appears to the engine of their airplane being unreliable, as as the commander complained about it to Stalin.