Hercules test fan

Hi all I;m looking for any one who can help me gather some information on a Hercules test fan, this is a single blade fan made from wood here are the markings on the fan.

Hercules 111-X-X1
DRG No 3430 51

I believe they come from the Bristol Airplane company and is possibly from the mid 1930’s
if anyone is able to give me any info I would appreciate it