The SPAD 13 entered service at the very end of the 'pale yellow' period and most would be delivered in five colour camouflage. Guynemer's S-504 however was of the first production batch and finished according to the existing standard of clear dope over unbleached linen with metal panels painted Ecru, here extending to the undercarriage chassis. The fuselage sash was originaly plain white and it is possible that red and blue were added in response to the DH4 attack. My French reference shows the fuselage numeral as red but it could be black. National cockades and rudder striping reflect regulation practice. Note the presence again of the black triangular fannon on the turtle deck but that 'LE VIEUX CHARLES' does not appear anywhere on the airframe. Perhaps time did not permit.
Designated the SPAD 13 the new fighter bore a strong family resemblance to its stablemate but differed in many important respects. A shorter and deeper fuselage than the SPAD 12 housed the same troublesome 200hp Hispano Suiza in a cowling which returned to the sloping lines and faired camshaft covers established on the SPAD 7. Both types had wings of similar round tipped planform, but those of the SPAD 13 were of greater span and rigged without forward stagger. All movable surfaces were larger and of curved outline and coupled to a more conventional system of control. Most importantly however the SPAD 13, with its two Vickers machine guns replacing the mixed armament of the SPAD 12, was the first orthodox twin gun fighter to be produced in any real quantity by the French aircraft industry.
Vigorously attacked by a British DH4 whilst flying the SPAD 13 and not knowing whether it might be a captured aircraft Guynemer was forced to return fire. The offending British pilot would have been unfamiliar with the outline of the new SPAD, the number then in service was fewer than twenty and would not rise to significant levels until the following year, and perhaps also mistook the black and white cigogne for a German cross. He is reported to have been most appologetic when told who had shot him down. Alternating with the SPAD 12 Guynemer would score only one of his victories on the SPAD 13, his last a DFW on August 20th, but it has a place in his story as the aircraft in which he met his death.