The Bird of Paradise was a military airplane used by the United States Army Air Corps in 1927 to experiment with the application of radio beacon aids in air navigation. On June 28–29, 1927, the Bird of Paradise, crewed by 1st Lt. Lester J. Maitland and 1st Lt. Albert F. Hegenberger, completed the first flight over the Pacific Ocean from the mainland, California, to Hawaii. For this feat the crew received the Mackay Trophy.
The Bird of Paradise was one of three Atlantic-Fokker C-2 tri-motor transport aircraft developed for the Air Corps from the civilian Fokker F.VIIa/3m airliner design. Its two-ton carrying capacity gave it the ability to carry sufficient fuel for the flight and its three motors provided an acceptable safety factor in the event one engine failed. Moreover, although modified for the long distance flight, the C-2 was a widely used standard design, demonstrating the practicality of flying long distances.
Although the recognition accorded Maitland and Hegenberger was less in comparison with the extensive adulation given to Charles Lindbergh for his transatlantic flight only five weeks earlier, their feat was arguably more significant from a navigational standpoint.
Background Planning for a transoceanic flight began in February 1919 at McCook Field in Dayton, Ohio, by members of the Air Service, the immediate forerunner of the Air Corps. 2nd Lt. Albert F. Hegenberger, an MIT-trained aeronautical engineer assigned to the Air Service Engineering Division, established the Instrument Branch to study ideas in air navigation (or avigation, as it was referred to at that time), and produce "new developments in compasses, airspeed meters, driftmeters, sextants, and maps." Hegenberger educated himself in over-water flight by attending a U.S. Navy course in navigation at Pensacola, Florida, that included flights over the Gulf of Mexico practicing dead reckoning and celestial navigation.
"For several months the Army Air Corps has been considering the possibility of having one of its most recent models of transport airplanes fly from California to Hawaii. The object of the flight primarily is to subject navigation instruments to a thorough test in practical use. The flight to Hawaii necessitates traversing the air for over water and, therefore, presents unusual problems." Air Corps News LetterJune 27, 1927Air Corps News Letter June 27, 1927; Vol. XI No. 8, p. 181
The Engineering Division, which evolved into the Air Corps's Materiel Division,The Materiel Division was created at McCook Field in October 1926 from the Engineering Division as a result of the Air Corps Act of 1926, and placed under the command of new Assistant Chief of Air Corps Brig. Gen. William E. Gillmore. () developed a multitude of pioneering flight and air navigation instruments that enabled civil as well as military aviation to reach its potential. In perfecting the equipment in hundreds of tests, McCook Field's engineers and test pilots also created new navigation methods in collaboration with other agencies, including the Navy. A program for a transpacific flight from California to Hawaii (over a distance officially considered by the Army to be ) was developed in February 1920 by the Instrument Branch and simulated many times during testing.
While the primary goal of the Instrument Branch was effective instrumentation, development of an all-weather and night navigation capability contributed to a larger goal espoused by the Air Service's Assistant Director, Brig. Gen. Billy Mitchell: extending the mission of the Air Service beyond the doctrinal role of "auxiliary" ground support. Mitchell's strategy was to generate public support for growth of military aeronautics and funding of the Air Service by a publicity campaign using air shows, flight demonstrations, and the setting of various aviation records. Among those participating in the varied events was 1st Lt. Lester J. Maitland, assigned to the Testing Squadron at Wilbur Wright Field, Ohio. Maitland was transferred to Hawaii in May 1919 for a two-year tour. There he submitted a request to the Chief of the Air Service to organize a transpacific flight between Hawaii and the mainland using the new two-engined Martin NBS-1 bomber, a prototype of which had been at McCook Field. When his first request was refused, he renewed the request in 1924 from Wilbur Wright Field, now called the Fairfield Air Intermediate Depot (FAID), while on temporary duty as a staff officer for Major Augustine Warner Robins.
At McCook Field in 1923, Hegenberger (who had also become a Robins protégé) worked closely with engineer Bradley Jones, a leading authority on air navigation, to test and adapt for military purposes an earth inductor compass developed by the Pioneer Instrument Company in conjunction with the National Bureau of Standards.In Fiscal Years 1921–1923, the Air Service allocated $4,000 of its experimental funds to the Bureau of Standards to develop specifications for the earth inductor compass, and then contracted with two manufacturers to purchase nine, delivered in December 1922 and January 1923. The first earth inductor compass in history was flight tested at McCook Field on May 26, 1923. (Air Corps News Letter June 3, 1927; Vol. XI No. 7, pp. 167–169). Hegenberger designed an instrument panel incorporating the earth inductor compass, a driftmeter, and a magnetic compass for a navigation station at which sextant readings could also be taken; and a cockpit panel with a dial connected to the navigation station that indicated to the pilot if he was steering to the right or left of the course set by the inductor compass. On September 6, 1923, Hegenberger and Jones successfully tested the equipment by navigating from Dayton to Boston, Massachusetts in a DH-4, above unbroken clouds that completely prevented them from seeing any landmarks on the ground.
Hegenberger transferred to Hawaii later that year, where he persistently submitted written requests for a transpacific flight that like Maitland's were repeatedly refused.Of their numerous requests to him (which he quipped "bored me to death"), Major General Mason Patrick, Chief of the Air Corps, explained that his refusals had been because "the time was not yet ripe" for the attempt. (Air Corps News Letter August 9, 1927; Vol. XI No. 10, p. 240; reprinted in ) In October 1926 Hegenberger returned to McCook as chief of the Equipment Branch, where he worked with the Signal Corps Aircraft Radio Laboratory at FAIDThe lab had formerly been the Radio Branch at FAID, where it tested the direction-finding concept as part of the Air Service's "Model Airway System," an experimental airline (and the first regularly scheduled cargo and passenger air system in the United States) begun in June 1922 between McCook, Bolling, Mitchel, and Langley Fields. Radio direction was used to guide aircraft between Chanute Field, Illinois, and Langin Field, West Virginia, where beacon stations were situated. Langin was a small field next to the Ohio River in Moundsville, West Virginia, used from 1921 to 1932 as a midway refueling point between Dayton and Washington, D.C. The field was surveyed by Jimmy Doolittle in 1920 and built at Air Service request the next year. () in testing an "interlocking" navigation system that used signals from four-course radio range beacons to define an airway. He was authorized to plan a transpacific test flight from California to Hawaii to demonstrate the more difficult task of navigating not to a land mass but to "a tiny island in a big ocean," using radio beacons as a navigational aid. Hegenberger described the method:
An electric current is sent through the air at a set wave length and forms an airway along which the aircraft travels to its destination. The airway has three parallel zonesthe T, N, and A zones. The T zone is the center of the road. It is about two miles wide at its maximum. While his ship stays in the center zone the pilot gets the (Morse) code letter T (— "dash") through his receiving set. If he veers to the right, the T changes to an A (· — "dot-dash"); if he swings to the left, the T gives way to N (— · "dash-dot"). All the pilot has to do when he hears N or A is to correct his course.
The navigation equipment developed at McCook Field took the concept one step further by wiring the RDF receiver into the cockpit instrument panel. Three lights provided visual cues to the pilot: a red light that illuminated when the aircraft was left of the airway, a green light when it was to the right, and a white light between them that indicated on course when steadily lit.
In the meantime, in November 1926, Maitland was transferred from FAID to Washington, D.C. to be Assistant Executive Officer to Assistant Secretary of War for Air F. Trubee Davison. There he was tentatively granted authorization for a flight to Hawaii with Hegenberger as navigator, radio operator, flight engineer, and relief pilot, pending the results of field trials to be run on the aircraft selected for the task.
Preparations
Aircraft acquisition, modification, and planning
In 1923 the Air Service established many distance and endurance records, including using a modified Fokker T-2 transport to set an endurance record of more than 36 hours aloft (and seven other world records as well) during a single flight on April 17.Air Service News Letter (May 15, 1923), Vol. VII, No. 10, pp. 1–4. It followed this up on May 2 by making the first non-stop transcontinental flight across the United States, a distance equal to that of the flight to Hawaii. While proved capable of transoceanic flight, the T-2 had only a single motor.
In 1926 the Atlantic Aircraft Company (Fokker's U.S. subsidiary) produced a development of the internally braced high-wing monoplane design, the F.VIIa, powered by three air-cooled Wright J-5 motors instead of the single water-cooled Liberty 12 of the T-2. The Army ordered three of the "Transport Airplanes" in September 1926 to be designated C-2 and earmarked the first to be sent to the Materiel Division at McCook Field as the test bed for the radio navigational aid testing about to be authorized. This aircraft, Air Corps serial number 26-202, was diverted at Teterboro Airport, New Jersey, for modifications and became the last to be delivered. The wing mounts for the standard wing were replaced with the center section of the wing mounts for the XLB-2 bomberThe XLB-2 was Atlantic's prototype for a two-engined bomber, 26-210, and would have been the Army's first monoplane bomber had it been accepted. It was a development of the same cantilever monoplane as the transports. to support a larger metal wing fabricated by Atlantic.