China Clipper

by Robert Gandt

  The most advanced feature of the S-42 was her wing. To achieve the range and economy demanded in the performance requirements, Sikorsky realized he would need a wing of high-aspect ratio.* This meant a long, narrow wing, which would yield minimum induced drag and produce the highest coefficient of lift. But such a wing also presented serious problems of strength and weight. A “clean,” cantilevered wing, one without external bracing, would be too heavy, with excessive thickness at the wing root, to satisfy Sikorsky’s requirements. He chose instead a two-spar wing, braced to the fuselage by two extruded duralumin struts on either side. Despite the apparent clutter of the struts, this structure afforded a more efficient wing than would have been possible with a heavier, thicker, but more streamlined cantilever design.

  Even more extraordinary was the load that would be borne by the S-42’s wing. In the initial version, the new flying boat had a wing loading of nearly thirty pounds per square foot of wing area, a statistic that placed the S-42’s wing in the same category as the hottest racing planes and fighters of 1934. Such a high wing loading not only delivered long-range fuel efficiency, but would provide better turbulence and storm penetration. To the builders of the S-42, however, the wing-loading statistics spoke a single profound statement: Less structure would be used to carry more load.3

  There were risks and penalties associated with high wing loadings. Excessively long takeoff runs and high landing speeds were problems that would have to be offset by new design features. A highly efficient airfoil, designated GSM-3, was developed by the brothers Michael and Serge Gluhareff in the Sikorsky wind tunnel. A trailing edge flap, 68 feet in span with 185 square feet of surface, was designed to reduce the landing speed of the S-42 to 65 miles per hour, the maximum certifiable landing speed specified by the Civil Aeronautics Authority. The new Hamilton Standard controllable-pitch propellers could deliver the full torque of the Hornet engines at takeoff and then coarsen their pitch to provide cruising economy.4

  Much had been learned from the S-40. Although the empty weight of the S-42 was approximately the same as that of the S-40, her hull was 30 percent lighter, narrower by ten inches, and elongated by eight feet. Extensive testing in the wind tunnel and on the Housatonic River produced a cleaner, more efficient shape both in the air and on the water.5

  The construction of the S-42 prototype was completed soon after Christmas, 1933, but ice in the Housatonic prevented a first launching until 29 March 1934. With test pilot Boris Sergievsky at the controls and a delighted Igor Sikorsky in the right seat, she quickly passed her water trials. The next day, in the air, she fulfilled her builders’ hopes.

  Throughout the spring and summer of 1934, the S-42 collected world records like flowers from a garden. On 26 April she lifted over eight tons of payload to an altitude of sixteen thousand feet, far exceeding the existing record. On 17 May she flew to a record altitude of 20,407 feet with a payload of 5,000 kilograms (11,023 pounds).

  On 1 August 1934, the S-42 underwent her formal acceptance test for Pan American. On board were test pilot Boris Sergievsky, Captain Edwin Musick, Pan American’s chief pilot, and Charles Lindbergh. Lindbergh had asked to be excused. “There is no advantage in my being on [the] plane,” he telegraphed Trippe, “and I believe credit for breaking records should go to operating personnel.” Trippe was adamant and persuaded Lindbergh to participate.6

  A 311-mile closed course was laid out from the Sikorsky plant to the George Washington Bridge in New Jersey, over Staten Island and Long Island to Point Judith in Rhode Island, and back to the departure point in Stratford, Connecticut. Taking off at near her maximum gross weight of 37,000 pounds, the S-42 flew four round trips over the course. For purposes of observation from the ground, she flew at relatively low altitude, using an average 69 percent of available power, cruising at an average speed of 157.5 miles per hour. When she arrived for the last time over Stratford after seven hours, fifty-three minutes, fifty-eight seconds, the S-42 had added eight more world records to her account. In a single flight, the S-42 had vaulted the United States into first place in the world in the number of aviation records held.7 Significantly, the 1,242 miles she covered established her credentials as a true over-ocean airliner. The longest segment in the chain of transatlantic stepping-stones—Newfoundland to the Azores—was 1,240 miles.

  The Atlantic would have to wait. Although the S-42 would have sufficed as a fast transatlantic mail plane, she lacked the capacity to carry the required fuel and a payload of more than six or eight passengers. She had been designed for the South American routes where she could carry up to thirty-two passengers.

  The larger, longer-legged M-130, still on Glenn Martin’s drawing boards, was intended to be the transatlantic airliner. The logical routes to Europe were either from Newfoundland to Iceland, thence to the British Isles, or from Newfoundland to the Azores, or the more southerly track from Bermuda to the Azores. Each of these routes required the consent and cooperation of His Majesty’s government. Despite continued negotiation and political bargaining, Pan American remained unable to extract the necessary concessions from the British. The reason, despite the rhetoric from both shores of the Atlantic, lay in one simple truth: The British, in 1934, had nothing like the S-42 or the coming M-130. Until Imperial Airways, the British flag carrier, possessed an airplane that could commence scheduled flights from Britain to the United States, Pan American would find itself blocked from the British crown colonies.8

  The S-42 entered Pan American service in the fall of 1934. Flying the eight-thousand-mile route from Miami to Buenos Aires, she reduced the travel time from eight days to five. She introduced a new standard of air travel to the South American market and firmly established Pan American as the premier flag-carrying American airline.

  Meanwhile, Juan Trippe had taken a gigantic gamble. Betting on the Atlantic, he had ordered not only the Sikorsky S-42 flying boats, but he had also signed a contract with the Glenn L. Martin company for three of the even larger, more advanced M-130s.

  More than ever, he needed an ocean.

  *Long wing span versus a narrow chord.

  12

  Pacific

  In his New York office on the fifty-eighth floor of the Chrysler Building, Trippe kept a large globe. It had become his custom to measure great-circle distances on the globe with a string, then translate the measurements into flight time for his flying boats. For Pan American publicity releases, Trippe liked to be photographed studying his globe.

  The trouble with the picture was that a sizeable portion of the globe remained off-limits to Pan American. The world’s most trafficked ocean, the Atlantic, remained blocked. Landing rights at each stop on both the northern and southern routes were closed while negotiations with the British government dragged on.

  If not Europe, then where? Pan American was scheduled to take delivery of a fleet of oceangoing flying boats. Over what ocean would they fly?

  The greatest, bluest, emptiest expanse on Trippe’s globe bore the label Pacific Ocean. Named by Magellan, the Pacific belied its name, looming like a heaving void between America and the markets of the Far East. But the European airlines were already there. The French were flying to Indochina. The Dutch were in Java. Imperial Airways, in partnership with the Australian airline, Qantas, was on its way. An opportunity was about to be lost.

  At a glance, the shortest route from America to Asia appeared to lie across the top of the world, over the Arctic, via Alaska and Siberia. That route had already been surveyed, at Trippe’s behest, by Lindbergh in 1931. Though suitable during the summer season, the vital landing and docking facilities in the Arctic remained ice-blocked for half the year.1

  That left the South Pacific. To the astonishment of his own directors, Trippe announced that Pan American would cross the world’s widest ocean at its widest part.

  Vast stretches of empty ocean lay between the tiny island stepping stones that formed the 8,700-mile route to Asia. The segment from California to Hawaii would be the longest commercial
air route ever attempted. Beyond Hawaii, safe havens would have to be found on the atolls of Midway and Wake, mere dots on Trippe’s globe. Farther west, only Guam and the Philippines were presumed to be satisfactory since the U.S. Navy had already established operating bases there.

  The problems were immense. Even with the development of an airplane that could cover the great distances between islands, no aircraft or passenger-handling facilities yet existed. No one knew whether there was enough sheltered water to accommodate a flying boat. In the case of Wake Island, there was no habitation, no shelter, not even fresh water.

  But it could be done. Six months earlier, six U.S. Navy P2Ys had flown from San Francisco to Hawaii in under twenty-five hours. Pan American already had the S-42, the most advanced long-range aircraft in the world, with improved models on the way. Trippe had recently concluded a deal with Glenn L. Martin for the construction of three M-130s, a third larger in size than the S-42. He needed an ocean now. The Pacific, even at its widest point, would do.

  In June 1934, C. H. “Dutch” Schildhauer, a former navy pilot and flying boat devotee, became Trippe’s agent to accumulate the knowledge needed to begin the Pacific operation. In Washington Schildhauer learned that the Pacific islands they wanted to use, particularly Midway and Wake, were administered by no specific authority. Who, he wanted to know, granted or denied aerial access? Who could authorize construction of aircraft and passenger facilities?

  Midway, 1,300 miles west of Hawaii, had been developed as a cable station. Like most Pacific atolls, it was ringed with coral and had a lagoon of sufficient size to permit a flying boat to take off and land.

  Wake was another matter. No one seemed to know anything about Wake Island. The tiny cluster of atolls was originally found by the Spanish in 1568, then rediscovered by a British captain, William Wake, in 1796. Since then it had been infrequently visited by various passersby, and since 1899 was claimed by the United States as a trophy of the Spanish-American War. Only twelve feet in elevation, the island was the summit of an undersea mountain. On all sides, the water deepened abruptly, and there appeared to be no break in the coral ring around the atoll. There was a lagoon, though its depth and suitability for flying boats had yet to be determined.

  The question of authority was pursued in typical Pan American fashion. Hawaii, as well as Guam and the Philippines, posed little problem, but Midway and Wake were a gray area. Trippe launched a campaign to have them placed under U.S. Navy jurisdiction. In the fall of 1934 he petitioned Secretary of the Navy Claude Swanson for permission to operate through the island groups and to construct marine facilities on Midway, Wake, and Guam. To protect his investment in the facilities, he proposed a five-year lease at a rental of $100 per year.2

  As it happened, Trippe’s plans dovetailed with the navy’s concerns in the Pacific. The growing belligerence of Japan following WW I had begun to raise an alarm in both the State Department and in the navy. Having appropriated the Micronesian chain of islands in the western Pacific, Japan then dropped a curtain of secrecy around them, developing harbors and airfields in defiance of the postwar treaties. Intelligence gatherers in the navy feared that the islands were being developed not only as a protective fence guarding the gates of Japan, but also as a staging base for a possible eastward assault on American interests in the central Pacific. At the same time, the Japanese government loudly protested each overt American military venture into Pacific waters.

  So the timing of the Pan American proposal was fortuitous. The State Department found it desirable, in view of the Japanese attitude and considering the constraints placed on the United States by the treaty ceilings, to establish an American presence in the middle and western Pacific, directly beneath the noses of the Japanese. That presence would be somewhat legitimized in the form of a commercial airline.

  On 13 December 1934, President Roosevelt signed the order placing Wake, Johnston Island, Sand Island in the Midway group, and Kingman Reef under navy jurisdiction. The same month, Secretary Swanson granted to Pan American the use of naval facilities at San Diego, Pearl Harbor, and three months later approved Pan Am’s use of Midway, Wake, and Guam. Thus was cemented a relationship between the U.S. Navy and Pan American Airways that continued to grow throughout the next decade. Technology would be exchanged, crews cross-trained, fields, harbors, and navigational facilities shared, personnel transferred from naval service to airline service and vice versa. In the empty skies of the western Pacific, Pan American would act as the surrogate eyes of the navy.3

  On 27 March 1935, the SS North Haven, a freighter chartered by Pan American, steamed from San Francisco laden with tons of fuel, generating plants, construction materials, radio units, boats, prefabricated housing, foodstuffs, tractors, dynamite, storage tanks, windmills, and 118 men. The workers chosen for the project were adventurers with construction skills. Many were college students with engineering backgrounds. In overall charge of the expedition was William Grooch, a former navy pilot who had begun his airline career with NYRBA, been summarily dismissed by the hot-tempered Ralph O’Neill, then hired by Andre Priester as a Pan American pilot.4

  Pausing in Honolulu to take on additional supplies and more workers, the North Haven steered westward for Midway. Because of the encircling reef and the shoal water on all sides of the island, the North Haven was forced to drop anchor four miles out at sea. There, while the ship heaved and tossed, the crew of adventurers labored to unload their heavy cargo onto barges. They had to cross the jagged coral reef, land the supplies, then muscle them across the fine sand of Midway.

  While a construction crew remained at Midway to erect the airline village, the North Haven hoisted anchor and continued to the next island on the route, Wake.

  Their worst fears about Wake Island were confirmed. There was no shallow water in which to drop anchor. The slope of the nautical mountain dropped steeply on all sides to the floor of the ocean. Contrary to plan, because of the low elevation of the southern island and the likelihood of flooding, they would have to erect their village on the northern island of Wake’s hairpin. But due to the prevailing northerly wind the North Haven would remain off the southern side, with her anchor fixed to the reef, in order to unload the cargo. Worse, the lagoon was found to be precariously narrow and shallow for flying boat operations. Worst of all, they discovered that Wake’s lagoon was filled with hundreds of protruding coral heads, each of which could gut the fragile duralumin hull of an airplane.

  The adventurers, many now seasick and sunburnt, grimly went to work.

  Aerial navigation was another problem. How was a flying boat to find a tiny speck of sage and sand in the middle of the Pacific? The aerial navigator’s tools and techniques were little different from those used for centuries aboard sailing ships. Airborne navigation had never been practiced over a route this long. An error of only a few miles in the Pacific could cause an aircraft to miss its island target—an event guaranteed to end in calamity.

  Trippe turned this matter over to his young radio wizard, Hugo Leuteritz. Since 1928, when Trippe had lured him to Pan Am, Leuteritz had enjoyed Trippe’s unquestioning patronage while he labored to develop airborne direction-finding equipment.

  Leuteritz’s interest in aerial navigation amounted to more than a mere technical challenge. He had not forgotten his ditching experience aboard Pan Am’s Havana to Key West Fokker land plane when the pilot had missed the Florida coast. Since that day, Hugo Leuteritz had felt an abiding passion for navigational precision.

  The direction-finding system that Leuteritz now favored had been developed in England by a radio experimenter named Adcock. But Adcock’s device, which consisted of an antenna stretched around four telephone poles oriented to the cardinal points of the compass, was a low-frequency radio and therefore of little use for long-range navigation.

  Leuteritz experimented with the Adcock. He tried increasing the frequency, thereby shortening the wave length and increasing the range. He added a dipole to each of the four antenna poles,
which further increased the device’s range.

  Leuteritz conducted his research in secret. He received Trippe’s unfaltering support, since Trippe was convinced that the success of the operation hinged on the clippers finding their island bases, every time, without fail.

  By early 1935 Leuteritz was able to send a secret message to his boss: The long-range direction-finder was working! They should begin building the devices immediately. If the DF were installed at each terminus of an overwater route, an aircraft would be able to fix its position by radio bearing over the entire distance.

  There were skeptics in high places. To many of the aviation “experts” of the time, a Pacific air route was premature and foolhardy. No commercial flying boat had yet made it as far as Hawaii. The craft of aerial navigation was still inadequate. Trippe was advised by the chairman of the National Committee on Aeronautics to cancel his plans. The industry, declared the chairman, could not afford a disaster such as the one Trippe was preparing. Pan Am should pull back and wait until advancements in aircraft design and navigation made the Pacific a navigable route.

  Worried, Trippe sought out Leuteritz. He told him about the doubters in Washington. Was the DF, in fact, reliable? What if the equipment failed? Were they biting off too much?

  Leuteritz explained the extensive research he had performed on the system. The equipment, he told Trippe, had undergone thorough testing, first in the Caribbean and South America, and then on the West Coast. It worked. If Trippe wanted, he could come along and see for himself.

  Trippe shook his head. He needed no further convincing. He gave the order to go ahead.5

  The supply ship North Haven was already under way in the Pacific when Glenn Martin advised that delivery of the M-130 would be delayed. Trippe had already established a new Pan American Pacific base at Alameda, on the eastern shore of San Francisco Bay. Accords had been reached with the U.S. Navy and the State Department to use and develop existing facilities in Hawaii, Guam, and the Philippines. To anchor the western terminus of his Pacific route, Trippe had bought an interest in China National Aviation Corporation (CNAC) in March of 1933, thus establishing Pan American’s presence on the Asian mainland.6