would anyone know if a propeller could have been re used after an engine up grade? I have a WW1 Prop, the hub markings say 160 on the bottom and have 180-200 stamped on top, here are the blade markings

PS-178 MERCEDES
ST 200
D 280
NO. 16246
1/2 bolt holes
3 1/4 centerbore
5 1/2 bore depth

Also stamped on hub are markings & 3

I have a hunch that an earlier prop for a 160 HP plane could have been re used for the upgraded 180-200 engine? especially after reading here that engines were re powered.

The parent company determined the paddle profile of the propeller (it was part of their trademark) while the engine application determined its pitch and length. So different company profiles could be seen on an aircraft.

The different pitches determined the different horsepower of the installed motor. . ." Yours appears to have been designed lengthwise for a 160 - 175hp(F1466a)Mercedes inline motor with the pitch set for the 180 - 200hp version. It could be used on any aircraft that would have used this 175hp D.IIIa - 180hp D.IIIaü or 200hp D.IIIav.

By the way the horsepower ratings discussed here are German hp minimums not maximums.

Very timely update; I thought recently of this post and thought I'd look for it; here it is!
Cheers,
Lance

Which Aircraft would we narrow this down to?

Without seeing an image this sounds like a replacement propeller. Each aircraft coming to the front usually had two propellers in its list of stores. If its pristine (no nicks or gouges)and since it sounds like it has no branding at the base of the blade (usually a serial # of the airframe it is for). It may have never been on an airframe operationally.

It seems that each manufacture delivered the aircraft with one propeller and there were there were two other manufacturers delivering diferent propellers as spares. Thus each variant had three approved propellers. Another airframe change was the dual rudder controls, two separate rudder horns and paired cables.

Spares are something that is rarely discussed. However with each airplane the German manufacturers, spares were delivered also. spares also included major components as well as hardware, wood, fabric, dope, paint and on and on. There were supposed to deliver 2 engines for each machine, one in the airframe and the other as a spare. Engines, and machine guns were government furnished items, the aircraft manufacturer did not buy them. With the critical engine production situation, that would have meant, the German engine manufactures would have had to deliver almost 100,000 engines during the war, there was less than one engine for each machine delivered.

The late Dan San Abbott wrote, ". . .The Spares included every thing that would be needed to maintain the aircraft in service. Items that were common breakage, such as Propellers, tailskids, wheels, shock cords. The radiators had high numbers in the spares list. These items were in the Forward Airpark along with gasoline (benzene), oil at the Tank Stelle, (gas station). The remaining spares were held at the Armee Flugpark. . ."