Bleriot XI - Helice Normale
c. 1910

B - 278
Comments: This very rare example of an original pre-WW1 propeller was built by Ratmanoff in France under the tradename "Helice Normale" probably in late 1910 or early 1911 for the early model Bleriot XI aircraft.  It was designed to be fitted to the early Anzani 3 cylinder engine producing 25 HP.  It is in nearly perfect original condition with evidence that it had been mounted and actually flown.  A Bleriot XI, flown by Louis Bleriot himself, was the first aircraft to cross the English Channel (July, 1909),  making Bleriot an instant celebrity. 

The offset blades and squared tips were characteristic of the Ratmanoff design.  See below for details of the verification of its use on the Bleriot.

Wood:  Unknown, probably walnut
Length:  210 cm
Bleriot XI
Anzani 3 Cylinder Engine
Thanks to Pierre-Michel Decombeix, a French expert on wooden propellers, for researching details of this propeller and providing me with images of an original 1910 "Helice Normale" price list showing features identical to this propeller, which clearly establish its usage for the Bleriot XI. 
This 1911 French publication includes a listing for Normale propellers.  Note that the "B" designation, which is stamped on this propeller, is assigned only to the Bleriot XI with the 25 HP Anzani engine, and is the only propeller with a diameter of 210 cm., as this one is.  Although there are other Bleriot XI propellers listed, they are different diameters and designated for higher horsepower Anzani engines.  A separate document at the Musée de l'Air et de l'Espace in Le Bourget shows that the price for this propeller in 1910 was approximately $65!
"Helice Normale" drawing schematic
Type "B" Normale propeller, 210 cm diameter, used on the 25 HP Anzani version of the Bleriot XI.