I was surprised to see a Yak 9-UM reproduction WWII Russian premier fighter plane at an air show many years ago. I liked the moisture swirls in the air from the propeller on takeoff. Researching I found out it was 1 of 10 Yak-9’s reproduced by the Yakovlev factory in the 1990’s. The plane was built in the original factory and machining from WWII. But this time it is a 2 seater with full dual controls. The original Yak 9 was the ultimate Russian WWII fighter plane. It sort of had P-51 Mustang performance at half the price for warbird flying enthusiasts! It was a very humid morning so the propeller made interest swirls in the air on takeoff!