Frankie Thomas only made one serial, Universal's "Tim Tyler's Luck" (1937), based on the newspaper comic strip of the same name. Frankie played the title character who was in Africa searching for his missing father who had been kidnapped when he found the mythical elephant's graveyard but refused to disclose it's whereabouts.
A busy actor he appeared in A-Pictures like "Boys Town" (1938) as well as B-Pictures such as "Nancy Drew, Reporter" (1939).
He is probably best known today for staring in the early fifties TV show "Tom Corbett, Space Cadet". A show many consider to be a precursor to "Star Trek" in it's attempt to show futuristic science in a believable fashion.