In 2003, while the world celebrated the centennial of the Wright brothers’ first flight at Kill Devil Hill on the Outer Banks of North Carolina, Maynard Hill traveled to the coast of Newfoundland, Canada to launch a flight of his own. At the age of 77 and legally blind, Hill launched an eleven-pound model airplane for an epic 38-hour, 1900-mile trans-Atlantic flight to Ireland.
The path to this amazing flight started in 1926, when Hill was born in Pennsylvania. He recalls building his first rubber-band-powered model airplane and the thrill of launching a 30-second flight. Now living in Silver Spring, Maryland, Hill jokes that model building caused a lifetime addiction to balsa wood and glue. He built models throughout high school, during his World War II Navy aviation service, and during his years at Penn State, where he received degrees in metallurgy in 1950 and 1951.
Over the years, engines replaced rubber bands, but flight control remained a challenge. One option, radio control, had been pioneered by notable physicists Walter and William Good, and in 1934, the teenage twins became the first amateurs to achieve radio-controlled flight. In 1947, Hill traveled from Penn State to meet Walter Good, by then a Ph.D. employed by the John Hopkins Applied Physics Lab, at his home near Washington, D.C. It resulted in a weekend of radio control talk and a lifetime of friendship and mentoring.
At the time, vacuum-tube-based radio control was complicated and had limited capability. Hill struggled for two years before he achieved a marginally successful radio-controlled flight with a descending glider by means of stepping the rudder position. Radio control capability advanced rapidly after the invention of the transistor in 1947, as transmitters and receivers were developed that provided variable control of the throttle, ailerons, elevator, and rudder. Radio-controlled flight became a new fascination for Hill.
Combining Hobby and Career
Upon graduation from Penn State, Hill took a research position with the Westinghouse Company in Pittsburgh. He continued to dedicate his spare time to radio control and activities sponsored by the Academy of Model Aeronautics (AMA) and Federation Aeronautique Internationale (FAI). He later organized the Society for Technical Aeromodel Research (STAR), which helped sponsor the trans-Atlantic flight.
In 1960, Hill went to work at the John Hopkins Applied Physics Lab so he could collaborate with Dr. Walter Good. Hill’s research focused on high-temperature materials and unmanned air vehicles (UAV), and he later formed his own company for UAV research, design, and development.
Good arranged for Hill to be the chief judge for the World Championships for Aerobatics in 1962. It was held at Kenley Airfield, where 20 years earlier, Royal Air Force (RAF) fighters took off to engage German bombers during the Battle of Britain. This took place at the height of the Cold War and the year of the Cuban Missile Crisis. The Soviets led the United States in space technology. Pietrov Velitchkovsky attended the championships wearing a “Hero of the soviet Union” badge, having already held seven world records, including the top altitude of 7100 feet. Hill realized the Soviets were excelling despite the handicap of inferior materials and radio equipment, so he returned to his District of Columbia Radio Control Club and preached that Americans should be doing much better.
Hill proceeded to build and fly airplanes to break all of Velitchkovsky’s records. He started by almost doubling the record altitude with a flight of 13,320 feet. By 1970, he had established new records for duration, speed, and straight line and closed circuit distance, along with altitude records for seaplanes and gliders. By 1992, he extended the duration record with a flight of 33 hours and 39 minutes.
During that time, Hill had joked about a trans-Atlantic flight. Then, the deployment of the Global Positioning System in the 1990s provided an opportunity in that it could serve as an autopilot. The quest began in 1998.
Executing a Flight Plan
The shortest distance across the Atlantic is 1900 miles from Newfoundland to Ireland. Hill devised a plan to take off from Newfoundland under manual radio control, transfer to autopilot for the ocean portion, and transfer back to radio control for landing by another team waiting in Ireland.
FAI requirements limited airplane takeoff weight to eleven pounds and engine displacement to 10 cubic centimeters (.6 cubic inch). The preferred four-cycle engine had been out of production for two decades, so Hill advertised on E-Bay to buy a stock of these. He replaced the glow plug with a spark ignition with a Hall effect sensor for timing and added a generator to eliminate battery weight. Coleman stove fuel was used because of its low carbon buildup, with an additive for lubrication.
Hill installed a smaller carburetor for fuel efficiency. The stock engine could muster one horsepower, but level flight required only about .15 hp. A relatively large wooden propeller of 14-inch diameter and 12-inch pitch resulted in an air speed of 43 mph at 3900 rpm.
With a 72-inch wingspan, the airplane looked conventional except for a sleek fuselage. It was named “The Spirit of Butts’ Farm” in honor of aviation pioneer Beecher Butts. In 1999, the vigorous and inspiring 88-year-old continued to fly his ultralight aircraft. Beecher made his farm available to Maynard for flight testing and, more poignantly, for handicapped and terminally ill children.
Developed by team member Joe Foster, the autopilot for Hill’s plane weighed only a few ounces. Performing a smooth transition from manual to autonomous control and then back to manual for landing posed a challenge. Great circle segments were programmed into a microprocessor and compared with the actual position measured by GPS. Servos moved the throttle for engine speed control, the elevator for pitch and altitude, and the aileron for steering and leveling the wings. A single aileron was used, to limit weight.
Almost half of the 11-pound takeoff weight was fuel. Engine speed was programmed to increase moderately during the flight as the airplane became lighter and drag decreased. Programmed at 1000 feet, altitude was measured by an air-pressure-based altimeter and periodically corrected with GPS measurements. The aileron controlled rate of turn, measured with a piezoelectric gyro. Operating conditions were transmitted by radio telegraphy, with data including airplane position, altitude, speed, and heading as well as engine speed and control surface positions.
Just as the Wright brothers made several long trips from Dayton, Ohio to the Outer Banks of North Carolina to prepare for their epic flight in 1903, Maynard Hill traveled for three years from Maryland to the coast of Newfoundland. During his first trip in 2001, he studied the terrain and met Carl Layden of the Model Aeronautic Association of Canada, who would serve as the official FAI observer. Hill planned to use a motel room for a workshop, but he was delighted when former Royal Air Force bomber pilot Nelson Sherren learned of the mission and offered the use of a large shop with workbenches, tools, an oscilloscope, and computers.
Back in Maryland during the winter and spring of 2002, Hill constructed 21 fuselages and 12 wings. He added red dye to his glue to compensate for his impaired vision. Many radio control clubs invited him to their gatherings to demonstrate his construction methods.
The design for minimizing engine power and fuel requirements was crucial to the success of the project. It required laminar flow on all surfaces and minimal cross sections. The resulting airplane had a lower drag coefficient than the legendary P51 Mustang. Hill built a customized dynamometer and spent hundreds of hours measuring engine performance, endurance, and fuel consumption over a variety of conditions.
The Real Test
After a van was procured in July 2002, Hill’s wife Gay drove him, the airplanes, and the equipment on a six-day journey from Maryland to Newfoundland. The first attempted flight started successfully on radio control but failed to stabilize when Joe Foster sent the radio signal to transfer control to autonomous flight. They suspected the airplane was too far out of trim for the transition.
They made adjustments, and the next launch started successfully and transitioned smoothly to automatic flight. However, the automatic navigation system flew the plane straight toward the Azores rather than Ireland due to a software error. Joe Foster and Les Hamilton corrected it over the next three days as they recalculated, resimulated, installed patches, and searched for other problems in 10,000 lines of computer code.
The engine also indicated problems that required further testing, prompting Hill to return to Maryland for more building and testing. Good fortune came in the person of a bright and enthusiastic high school student named Cyrus Abdollahi, who had done UAV research at the John Hopkins Applied Physics Lab. A gifted builder, skilled radio control pilot, and computer whiz, Abdollahi became a vital contributor in the winter and spring of 2003 and then joined the team in Newfoundland for the summer.
The first attempted flight on the evening of August 8, 2003 saw a smooth departure. Signals from the airplane indicated a flawless flight in terms of course, airplane speed, altitude, engine speed, and trim for the first eight hours. But then suddenly at 430 miles, the signal vanished without warning.
The team launched the second airplane on the evening of August 9. Preparations were rushed to take advantage of a favorable weather forecast. On Sunday morning, it was still flying after 560 miles, but engine speed and altitude were unsteady, indicating slow climbs and rapid descents.
The unsteady flight continued until early Monday morning, when the signal was lost. Prospects looked bleak, but Abdollahi kept his youthful optimism and continued to monitor from his laptop computer. A few hours, later the signal returned. The engine speed and altitude had stabilized, and the flight was on course. They later learned that the communications relay satellite had set without downloading the data. When the satellite rose in its orbit, the signal returned.
The fuel situation made the last hour a cliffhanger. Winds had proven less favorable than predicted. The flight had started with an estimated 36 hours’ worth of fuel with a slightly rich carburetor setting, and the airplane had flown for 37 hours when it came within sight of Dave Brown waiting in Ireland.
A past member of six U.S. World Champion Radio Control teams, Brown expertly transferred the airplane to his radio control, cut the engine, and glided the plane for a dead stick landing near the monument that marks the historic landing spot of John Alcock and Arthur Brown. The two RAF officers had flown the same route in 1919. Dave Brown’s wife Sally called Gay Hill in Newfoundland with the news. A triumphant Maynard Hill wept on his wife’s shoulder with tears of joy.
Orville and Wilbur Wright’s 1903 flight received little public attention at the time, and similarly, the flight of Hill’s model airplane across the Atlantic received little notice. But it demonstrated how new technologies allow unmanned flying machines to perform many types of missions more effectively, cheaper, and safer than human-piloted aircraft.
After seven decades of addiction to balsa wood and glue, Maynard Hill had broken plenty of records in the model airplane world, but this time, he had scored his greatest triumph.
Editor: Tom Gibson
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©2011 Progressive Engineer