[Does so]

The point is the Soviets has stuck with a technology from the early 1930s with Stalin’s purges.

Agreed—and nothing against biplanes, either. As I stated, Russian designs have always impressed me.

"...U-2 biplane in Night Witches’ use weren’t even a combat planes..."

'Didn't write that—but "ground-attack" ain't bad—

Fascinating reading:

http://webcache.googleusercontent.com/search?hl=en&q=cache:7JKwZD6IGpAJ:http://en.wikipedia.org/wiki/Polikarpov_Po-2%2BU-2+biplane+in+Night+Witches%E2%80%99&gbv=2&ct=clnk

[cunning_fish]

Night Witches actually inflicted little damage to the Nazy. Their primary mission was harassing Germans at nights. If you remember MASH series and their 5 o’clock Charlie it is exactly that the Witches did. Little to none effect but the enemy is nervous and constantly thinking how to deal with you.
Primary Soviet ground attack planes were Il-2 and Aircobra.