I've digged a bit into the question.
Up to 1949 original Yak-18 were fitted with ВИШ-327ЕН prop. Since early 1949 new prop named ВИШ-501Д-81 was fitted.
But the newer prop spinners were prone to cracking, sometimes detaching in flight and damaging prop - problem was finally solved only starting from year 1952, with more than 15 different modifications of spinner between those dates.
Due to that fact - in the clubs and schools spinner was dismantled just after new planes arrived and thrown away.
I need:
1. confirmation of prop model name you have
2. maybe a photo of attaching backplate if it is available
I've made a contact to several local restoration guys, maybe they have something in their treasure houses.
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Regards,
Ivan Postnikov