Mikoyan MiG-21 Fishbed and its Three Generations

Recently I bumped into a lot of articles regarding Mikoyan-Gurevich MiG-21 and mostly its Bison variant. In many of them, this is quoted as a 4th generation MiG-21 and 3rd and sometimes even fourth generation jet fighter, none of which is true.
MiG-21 and its variants are divided into three main generations. It is a rather confusing subject and with this video I will try to clear that up, expressing my point of view and my knowledge based on the research that I've done.
Modeling-wise, I won't go very deep, but will barely touch the surface of the subject. Unlike most of the videos in my channel, this will be more real-life oriented one.
Mikoyan-Gurevich MiG-21 #Fishbed is a legend, approaching its 70th birthday and I believe that it deserves it.
Hopefully you will find it helpful and it will clear the mist, especially around MiG-21 Lancer and #MiG21 Bison variants, alongside with the rest.
To sum it up here:
1st Generation #Mikoyan-Gurevich MiG21s are:
MiG-21F, MiG-21F-13
2nd Generation MiG-21s are:
MiG-21PF, MiG-21FL, MiG-21PFS, MiG-21PFM
3rh Generation Mikoyan-Gurevich MiG-21s are:
MiG-21M, MiG-21R, MiG-21SM, MiG-21MF, MiG-21SMT, MiG-21bis
Upgrade packages of the Mikoyan-Gurevich MiG-21s are:
MiG-21 Lancer /MF/, MiG-21-93 /bis/, MiG-21-97 /RD-33 engine/.
Lancer and -93 AKA Bison are in use, MiG-21-97 never happened for the customers.
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