M.M. Smodor. Airplane for agitation. Russia, Kostroma 1931

Source

It struck me as odd why they’d aerodynamically designed the cockpit but not the front – then furthermore that you never see the radiator on similar era planes at all (at the front, like on a car). Turns out they’re usually under the wing or nose and a lot smaller than this:

http://www.ipmsstockholm.se/home/wp-content/uploads/2012/02/detail_spit24_03.jpg