AB 644 RH
N 19180
This is one of several applicable propellers used on the famous Sopwith Camel using either the Clerget 130 HP engine or a Bentley BR1 engine.  The "AB 644" drawing number identifies it as "Air Board" (later Air Ministry) designation.

Wood:  Mahogany
Length:  2590mm  (8feet, 6inches)
Pitch:  2650mm
Sopwith Camel
c. 1917
WW1 Aero listing from a 1918 publication