United States naval aviation had made slow but steady progress in the years just preceding World War I. Bombing and scouting practice was engaged in by naval planes and considerable headway was made in the development of larger flying boats and amphibians. When war was declared in 1917, naval aviation consisted of 54 airplanes, 38 pilots, and 163 enlisted men. By rapid expansion it had reached the strength of more than 50,000 men and over 2,000 airplanes by the end of the war. Some 17,000 men and 540 airplanes were sent abroad during the conflict. Extremely successful anti-submarine and patrol operations were carried on throughout the war, and our naval aviators served with great distinction. Our early models of big flying boats, like the F5-L above, were so successful that the Navy ordered even larger ones. The “big boats” as they were termed, were giant four-engine planes with a wingspan of 126 feet, the largest built to that time. Their size created a difficult shipping problem and it was decided that they were to be flown overseas. Commander John H. Towers, pioneer naval operator, was assigned to the task of supervising their construction and flight tests. The planes were ordered in December, 1917, and ten months later the first of the “big boats” proved its ability in a series of test flights. The planes were designated the NC’s, Navy Curtiss. With everyone rushing madly to finish the NC’s for their overseas flight, the war ended abruptly. [Illustration: 1919 WINGSPAN 126 FEET LENGTH 68 FEET POWER FOUR 12-CYLINDER 400-HP. _LIBERTY_ ENGINES THE GIANT CURTISS NC FLYING BOATS WERE THE LARGEST PLANES THAT HAD BEEN BUILT AT THAT TIME. THEIR BIG WINGS SPANNED A DISTANCE GREATER THAN THAT COVERED IN THE FIRST AIRPLANE FLIGHTS. SPEED ONE HOUR 100 MILES RANGE 2,000+ MILES CEILING 5,000+ FEET PAYLOAD SIX-MAN CREW THE BIG BOATS HAD A GOOD TOP SPEED CONSIDERING THEIR SIZE. THEY COULD CARRY 1,800 GALLONS OF GASOLINE, AND ON A TEST FLIGHT ONE NC FLYING BOAT SOARED ALOFT WITH 51 PASSENGERS. THREE PROPELLERS WHIRLED IN FRONT OF THE NC’S WINGS AND ONE OTHER, A PUSHER, TURNED BEHIND THE CENTER OF THE WINGS. THE HUGE NC FLYING BOATS WERE THE FIRST FOUR-ENGINED AIRPLANES BUILT IN THE UNITED STATES. THEY NOT ONLY PROVED THAT WE COULD BUILD BIG AIRPLANES, BUT THAT SHIPS OF THIS TYPE WERE PRACTICAL FOR OVER-OCEAN FLIGHTS. THEY ALSO SHOWED THE POSSIBILITIES OF GIANT, LONG-RANGE NEW PATROL PLANES.] [Illustration]