Hello Terry,

Welcome!

Your prop is an auxiliary prop from a WW1 aircraft, probably a British aircraft. Generally these came in two sizes;

Eleven to Thirteen Inches
These powered pumps, such as fuel pumps and also, it is said, oil pumps although I haven't myself yet found such an example.

Around Eighteen Inches
These powered electricity generators, generally at 250 watts and 500 watts.

Larger auxiliary props exist around 36 inches. These date from the 1930's-1950's and are from target-tug aircraft. They were deployed into the airstream to power the electric winch that let the drogue in and out.

Auxiliary props were not used for synchronising machine gun fire through the arc of a propeller because the prop rotated at exactly the speed of the engine whereas the speed of the airflow was very variable. In a stall for example it could momentarily be zero. So the machine gun synchronisation was matched to the prop shaft speed.

The concept of these auxiliary props lives on in the deployable ram-air turbine on modern large aircraft, where they are deployed into the slip stream to generate electric power if all engines are lost.

With kind regards,

Bob

propeller identification/ bob gardner

Thanks for your reply Bob. At least it confirms that the family story makes sense and isn't just one of those passed on and changed from the truth over the years. I know the family were living in the Leeds area (1910 Census) so were there any WW1 aircraft manufacturers in that area around that time that come to mind?

Best regards,

Terry

Hi Terry,

There was a major maker of WW1 props in Leeds, WD Oddy, who also made auxiliary props just like yours. I'd be suprised if yours wasn't made by him.

With kind regards,

Bob

propeller identification/ bob gardner

Thanks for coming back so quickly. It's easy to jump to conclusions but the Leeds connection is a bit of a coincidence! I'll see what else I can find out about Oddy's though I'm sure you'll already know quite a bit (any info gratefully received). I take it they were subcontracted to carry out production for the end aircraft manufacturer. Were they always involved in this type of work or did they become involved with the outset of the war?

Best regards and thanks again for your help,

Terry