Why did the Soviets need the Swedes to do that????I presume they had adequate tech themselves if you are talking about equipment.Besides,wasn’t Sweden wary of the Soviets??
The tolerances required for the silent props were beyond the crude means of Soviet industry. The Swedes, though they be socialists, will make anyone anything for $$$. The tungsten steel on the 88mm at rounds used by the Wehrmacht came from Sweden. The Bofors 40mm that shot down planes on all sides in WWII made Swedish socialism possible with the payments for its licenses to build.