The rules of the Schneider competition reflected his intent, although in a sometimes bizarre way. Aeroplanes had to float on the water for six hours and prove their seaworthiness by travelling a distance of about 550 yards (503m) on water. Twice during the flight portion, planes had to land on the water (or “come in contact with” the water, the wording of which stipulation gave rise to a bouncing manoeuver invented by Pixton in 1919 that cut time from the race).

If the pontoons took on water, the planes had to continue the flight portion with the added weight. The rules called for the trophy to go permanently to the country that won three consecutive competitions; each competition was to be held in and managed by the country currently holding the trophy. Two contests were held before World War I—in 1913 and 1914—both off the coast of Monaco. The planes raced in these years were land planes fitted with clumsy pontoons haphazardly attached to the underside of the fuselage.

Maurice Prevost, the French pilot who won the first race in a Deperdussin, was the only pilot to finish, his pontoons heavy with water by the time he crossed the finish line. The following year, Tom Sopwith and Harry Hawker brought to the race a Tabloid plane equipped with pontoons and piloted by Howard Pixton. Pixton’s bounce won the race for the British, though the French were quick to point out that the Tabloid used a French built Gnome engine and that Pixton’s bounce manoeuver was largely responsible for his nearly halving the previous year’s time. The race was suspended during the war and resumed in 1919 at Bournemouth near the Isle of Wight off the English coast.

The race was a fiasco—the facilities were inadequate, and a British ploy that confused the Italian entrant into flying the wrong course resulted in the lone finisher, the Italian Guido Janello, being disqualified. The International Aeronautic Federation (FAT—for Fédération Aéronautique Internationale), the French administrators of the competition, appeased the incensed Italians and moved the race to Venice in 1920. The Italians had their revenge by pressing the FAT to add a weight requirement on the planes.

The sleek lines of the British Supermarine and of the other 1927 Schneider Cup planes make it apparent how much the war had accelerated aircraft design. Unfortunately, the planes did not taxi well on water and had to be towed by boat to the starting line.

By this time, the Italians had developed powerful (but slow) flying boats and a weight requirement favoured their aircraft. They won handily in 1920 and 1921 against a thin field. The 1921 race was held at Naples, and the French and British fielded several teams, determined to prevent an Italian victory. The winner was Henri Biard of England, flying the Supermarine Sea Lion II, a flying boat that had crashed in the 1919 race.

The race was a close one, and the pilot of the technologically inferior British plane (in spite of some inspired modifications by R.J. Mitchell) won by sheer piloting skill. Reports of the race were followed around the world and the Schneider Trophy was once again the premier aviation competition. The average speed for the race had climbed from eighty-six miles per hour (138.5kph) in 1914 to 106 miles per hour (170.5kph) in 1920 to 146 miles per hour (235kph) in 1922. It was not fully appreciated at the time, but the obstacles and hardships of the Schneider races actually helped rather than hindered the development of faster aircraft.

The mere fact that a more powerful engine was required to overcome the handicap of the pontoons made for designs that would, when adapted to land, allow for the setting of new speed records. The very long take-off afforded by the water allowed for smaller wings and thus less drag. And pilots flying over water were more daring and more prone to push their aircraft to its limits, being able to ditch in the sea in the event of trouble. The 1923 race was won by Lieutenant David Rittenhouse of the United States, flying a Curtiss CR-3. Several new elements had entered the race.

The Americans were now supported by the U.S Army and Navy, who saw the race as an opportunity to test and develop aircraft. The entire atmosphere of the race became more professional and the American team trained long and hard on a variety of aircraft. But the most important change was in the plane itself. The engine used in the Curtiss CR-3 was a newly developed CD-12 (for “Curtiss Direct Drive”), which used a cooling system invented by Charles B. Kirkham, employing a technology developed by the Swiss engineer Mark Birkigt. Instead of cooling the engine with an independent cooling system of tubes that carried heat away from areas remote from the sleeves that generated the heat, Kirkham created an engine out of a solid block of metal that allowed the  coolant to flow onto the sleeves directly.

This was known as the wetsleeve-monobloc engine, and it was to revolutionize aircraft design. The power-to-weight ratio went from 1:2 for the most efficient previous engines to an astounding 1:1.5. It also took up less space, which allowed a sleeker design.

 The requirement that the Schneider planes be seaworthy (1929 Italian entries undergo tests at sea) was viewed by the British as having great military significance.

The European planes had the edge technologically on the American planes (even after the S4 crashed in the pre-race trials), but the hairpin turns and expert flying of Lieutenant James Harold “Jimmy” Doolittle gave the United States its second win, with an average speed of 232.6 miles per hour (374kph). Both the British and the Italians were determined to prevent a third American victory; by now they had discovered the secret of the wetsleeve-monobloc and had abandoned flying boats for sleek single-wing seaplanes.