prop hub(only) w/ clock, on wooden base

[goosegreaser]

I'm looking at a two-bladed prop hub(roughly 18-20 in wide x roughly 6 in thick at the hub) mounted on a matching(dark stained) wooden base(screwed to the prop hub w/ large standard slotted screws) w/ a clock inside the hub, and the eight bolt holes on the front face are filled w/ metal plugs resembling rounded rivet heads. Stamped(indented) on the hub, reading it on edge from one of the blades, it has this notation in capital letters accompanied by numbers:
SAGE.NO104
AD619 RH
ROTA
DIA 2520 PITCH 177
150HPHISPANOSUIZA

The only things I can guess at are that it is a right hand rotation prop w/ a 2520(cm?) dia., and a pitch of 177(cm?) and made for a 150 HP Hispano Suiza engine. The clock has on it's face, at the bottom: "Made in France", but when you remove the tin-can-like rear cover, the movement has "Swiss made" stamped on it.
It is in a shop and I am considering purchasing it but am unsure if it is a copy or from a "real" former prop. I have been flying model planes since 10 yrs old(the past 56 yrs) and would like this for my den. So the big question is, is it authentic, and if so, what could its markings indicate about it's history?Thank you in advance for any information you can provide as to its authenticity/un-authenticity, history, and what the markings really mean.

[Bob Gardner]

Good Morning and welcome to the forum.

The drawing number of your prop (AD619) indicates it was made from November 1917 to the Summer of 1918 for the BE2C, D and E powered by the 150hp Hispano Suiza engine.

The AD in AD619 indicates it was designed by the Air Department of the Admiralty, although from November 1917 onwards under the auspices of the Air Board it was selected as a standard prop for both Army and Navy aircraft because it was superior or equal to other designs.

It was made by the Sage Company in Peterborough, England. This firm of well known shop fitters were recruited during WW1 to make aircraft and propellers.

This two bladed prop had a diameter of 2520mm and a pitch of 1770mm.

I don't know what ROTA means.

Sage props are very rare and this drg no had not been recorded before on a Sage prop. I have added it to my database and am grateful you told me about it.

You can be sure that it is authentic. If you buy it, I would be grateful if you could take a photograph for me that I could include in my book on British WW1 props.

With kind regards,

Bob