The SPS system stands for "Sduv Pogranichnovo Sloya" , Boundary Layer Blowing what means blown flaps. If the DDR Mig-21 no.913 is PF variant it means no SPS system installed. The SPS appeared with the PFS variant with narrow-chord fin and brake chute fairing at its base. Your pic shows there was no brake chute fairing at fin base. As a result , no SPS for the no.913.
Oh.. I didn't catch it properly. Yep, the no.813 was the SPS kite what is affirmed by its variant and serial : MiG-21SPS c/n 944703 s/n 813. Oh by the way .... the Mig-21SPS was nothing more than the Mig-21PFM for DDR. Therefore the large-chord fin seen in the images of the no.813 plane.
Poland MiG-21PF c/n 761913 s/n 1913
*8/1965: Delivered to the Polish AF.
*1965: 40 PLM.
*12/1989: Withdrawn from use.
*Currently preserved at a funfair in Chorzow.
I remember the Mig-21PF. It is a monument at the Mierzęcice airbase. It was set at the former military housing estate in 2006. From June 1965 was servicing with the 40th PLM in Świdwin. Then she was moved to the 34th PLM Babie Doły in 1977.
I think many PLM emblems can be found with the ModelMaker decal sheets. However not all squadrons were using them at the early service of MiG-21 especially for the PF/PFM planes.
Not exactly..... However the quite strict rules of colouring planes at the period of time didn't make it easier. I recall myself the entire hoo-ha when the emblem of my squadron appeared the first time on a Su-22 fuselage. Before that any of Lim-6bis for instance , used by the squadron, hadn't had it applied.
Hmmmm....just thought of something, got an email from Eduard on the 29th, that cockpit had been shipped, it's now the 11th and it's still not here, seems a bit long, doesn't it?