MiG-21 bis windscreen side glasses shape

[Laurent]

Hello.

A member of the ARC forum has posted an interesting link: http://jetphotos.net/viewphoto.php?id=6734935&nseq=0

The windscreen side glass shape is different between the two Polish aircrafts. I knew that Finnish MiG-21 bis aircraft could have "straight" side windows but I didn't know about the Polish aircrafts. Does someone know how many MiG-21 bis had "straight" side glasses ? Why were they introduced ?

Best regards.


Laurent