On defensive Patrol this morning I forced down a One winger. We were out by Loos at the return point when we over flew a flight of Monoplanes. I chased one in and out of clouds loosing my flight. Caught up to the e/a near NML across from Lens, In a series of passes I shot off 3 drums and his motor stopped. Upon landing, I had the ADJ call around and the 17th Chasseur, a recon unit of the 11th Battalion. 3rd Army said that a lone Hun plane came down in no mans land during a Arty Barrage just small parts were left about.