For this planform as early as 1909 a french engineer named Neuville got
a patent and in 1910 an aircraft with a slender delta wing and rounded
trailing edge was even built (in the photo it is shown without engine).
It really seems, there's hardly anything new in the world !
(from Aviation Francais Magazine N°2)
Sorry, you're right, I've forgotten to mention, what is said in the file name :
Constructors of the second delta were Gabriel Langé and Pierre Billard,
according to the mentioned AFM. Is there a photo in "French Aeroplanes .."
WITH the engine ?