http://www.innovari.it/gcr/Just%20Imagine%20-%201930.htm Professor Zarkoff's ship in the original FLASH GORDON serial seems to have been some props bought from Fox from their epensive flop musical JUST IMAGINE (1930).
Fox-Movetone, 1930, B&W, 113 min.
Just Imagine projected a sci-fi musical story set in New York City in the year 1980. The spaceship is the archetype of all art deco era spacecraft. It makes several additional screen apparences - slightly revised - as Dr. Zarkoff's invention in the Flash Gordon serials.
Picture from the book "The Dream Machine" by Ron Miller edited by Krieger Publishing Company
from FLASH GORDON.