In 1911 Coanda introduced his second design, similar to but also significantly different from his first. L'Aerophile of 1 January 1912 described the second machine:

   Pressing - and tactless - questions (about the earlier machine) were answered by a not-very-convincing explanation of the qualities of the turbine, and by the claim that the aeroplane had achieved test flights of up to 112 kmh. As in aviation nothing stuns, I approved without a word, though I decided to hold back until the proof of the experiments, which did not come. And the new machine, which appeared at the Concours Militaire (at Reims), where it raised some sharp dispute today, shows what remains... and what was given up. What was given up: the turbopropeller ("turbo-propulseur" (sic)) and the wooden wing-skinning, as well as the wooden fences to ease the regular fluid flow. What remains: the aerofoil section, the structure, and the general shape of the fuselage. All very interesting, but built somewhat differently.

   The fuselage of this second machine was fuller and more rounded than that of the first; only the front third was ply-covered. The cruciform tail remained, though without the extra horizontal surface. The top wing was of extremely high aspect ratio; only part was ply-covered, to facilitate warping. The fuselage was set between it and the lower wing, now only a stub between the 2 pairs of tandem wheels, each pair housed in a large triangular cover. Only one tall strut on each side supported the wings.
   The engine arrangement was unusual: 2 Gnomes were fitted into the nose, back to back, each facing outward, driving a single 4-bladed propeller through a differential gear-box. Coanda claimed that one engine could be cut in flight.
   At least one drawing shows it with extended lower wing panels. There is no reliable evidence as to its flying.

   (Span: 16.3 m; chord: 1.25 m; length: 12.5 m; gross weight: 1250 kg, with 170 kg of gasoline in the wings; empty weight: 470 kg; 1 pilot and 3 passengers; expected speed: 130 kmh; 2 70 hp Gnomes)

   At the same time, Coanda shared with Emoult the design of a racing monoplane built by Melin. After the military biplane proved unsuccessful, Coanda went to work in England at Bristols, where he introduced many refinements to reduce drag, and shared design work on the various Bristol-Coanda aeroplanes. In 1918 he designed an advanced biplane for Delaunay-Belleville, which was destroyed in a crash.
   Always busy with fluid-flow dynamics, he made important discoveries in this field, including what has been known since 1937 as the Coanda Effect.