The Engine Whisperer

“So well attuned to the roar of the two-cycle, four-cylinder [Roberts] engine had her ear become that the sound would tell her when the top power output had been attained.”
— George Shane, Des Moines Register

Mary Heidenreich Solbrig was a gardener, a cook, a church organist, a seamstress, a wife, and mother. She intuitively understood machinery and was good with hand tools. Her husband, Oscar, was a devoted family man and a skilled aviator. Their mutual interests in all things mechanical made them a remarkable team, trusting each other’s judgment as if their lives depended upon it. In fact, between 1911 and 1917, it did.

Oscar A. Solbrig immigrated to Davenport, IA, from Germany during the 1870s, set up a repair shop, and married Mary Heidenreich in 1894. Their cultural and religious heritages were similar, but what uniquely bound them together was a shared talent working with machines. They worked side by side, living in the back of his shop. They raised three children; Alfred, Hope, and Ruth. Fortunately, their private and professional lives have been chronicled in several newspaper interviews with the children as well as Mary’s personal journal. “Mama and dad . . . repaired guns, and bicycles,” recalls Ruth. “They often filed saws and sharpened blades and scissors. One time a man came in and he had a saw he wanted filed. Dad was ready to go back and file it but he said, ‘I want the woman to do it. She did such a good job.’ “

The lure of the air
The Solbrigs briefly lived in Washington, IA, during 1899, where Oscar helped Frank Brinton construct parts for his invention of a lighter-than-air ship to be exhibited at the local fair. The dirigible never made it off the ground, but Oscar’s mind soared. Mutually interested in the “new science of aviation,” the Solbrigs subscribed to aeronautical magazines to keep abreast of the latest technology, from balloons to aeroplanes. By 1910, the Solbrigs were both in their 40s, and their children were finishing high school. It was the Pioneer Aviation Exhibition Era (1908-1915) and the Solbrigs succumbed to the lure of the air.

Oscar’s goal was to fly professionally, earning $300-$500 a day while on tour in the exhibition flying circuit. A good season of “air-circus” flying easily surpassed the annual income from their shop. The risks of “cracking up” an aeroplane were well known to Oscar and Mary. They decided that they could diminish their chances for mechanical failures with Mary assigned as Oscar’s mechanician.

In 1911 Oscar took flying lessons from the Glenn Curtiss aviation school at Rockwell Field, San Diego. Mary was left to run the shop, and clear out the attic of their large home in Davenport where they planned to build a flying machine of their own. “The two of them always worked together on everything,” observed their daughter, Hope. Ruth concurred. “I don’t think [dad] would have been very much interested by himself.”

Hope remembered them “busy as bees” building the huge Curtiss biplane in the attic and in their living room. Oscar insisted upon a four-cylinder, two-cycle, 50-hp Roberts engine.

By the summer exhibition flying season of 1912, the Solbrigs’ Pusher was assembled, tested, and ready to fly. Mary, acting as manager and contract negotiator, had committed Oscar to appear in Iowa, Illinois, and Missouri. The couple locked up their shop and hit the rails traveling from town to town on the circuit.

A day at the air meet
The Solbrigs’ Curtiss was disassembled at the end of each air meet and packed in four crates custom made for the wings, outrigging, motor, and tools. The crates were shipped to the next location by train, wagon, or later, by truck. Mary and Oscar could re-assemble their aircraft in about four hours. If Oscar was unavailable to help her, Mary did the work alone except for lifting the engine. Once the machine was assembled, Mary and Oscar began testing the gear, with special attention to the piano wire and cables which were constantly stressed and subject to snapping apart mid-air. Once settled in for the air meet, Oscar slept while Mary remained awake all night to prevent theft and damage to their aeroplane. On the road they rested in tents, barns, and often inside their aeroplane shipping crates.

Most Americans had never seen an aeroplane, much less one in flight. The enthusiastic and naive public was unaware of the restrictions placed upon aviator and machine due to rain or wind. Inexperienced air meet organizers expected aircraft to fly straight up, without providing adequate ground for take-off and landing.

When Mary saw an obstacle in Oscar’s path, she refused to allow him to fly until trees were cut or fences torn down. Angry crowds as large as 10,000 often threatened to destroy an aeroplane and do harm to the aviator when a flying schedule was delayed or cancelled. “They didn’t come to see the airplane fly,” Mary once remarked, “they came to see the flyer killed.”

Oscar broke his collar bone and dislocated his shoulder in two separate accidents. Weeks of recuperation for Oscar and repairs to the machine ate into the profits earned, but as Mary put it, “If it were a good season, the hard work and risk had been worth it.”

During 1913, Oscar traveled to Hammondsport, NY, and attended Curtiss’s aviation school. There he spent more hours in the factory learning how to put together an aeroplane than he did flying. It was time well spent.

In the winter Mary and Oscar kept regular business hours in their shop, then concentrated on refurbishing, repairing, and testing the Curtiss. After her family went to bed, Mary often worked through the night cutting and fitting the linen fabric for wings.

During harvest season she alternated between mechanician and homemaker, canning and preserving vegetables grown in her large garden. “You had to have a garden or you didn’t eat,” Hope later recalled. “She was a good cook . . . It seems like there was nothing she couldn’t do.”

Mary made power plant and airframe repairs in their house and ran tests in their yard. The Solbrigs’ neighbors must have been good sports. Des Moines Register reporter George Shane complained that at top rpm, the Roberts sounded “like an outboard motor without the muffler.” Oscar once summarized the capriciousness of the temperamental Roberts. “One day the engine ran smoothly and the next it would be completely out of commission.”

A horse whisperer can intuitively understand and sooth an ill-tempered horse. In like manner, Mary Solbrig was an engine whisperer. She could detect the slightest mechanical irregularity and Oscar did not fly until she was satisfied the Roberts “ran smoothly.”

With WWI looming, Oscar joined the U.S. Army Aviation Reserve Corps in 1915 at the rank of 1st Lieutenant. Mary billed him as “Lt. Oscar A. Solbrig — Patriotic Programs — Mail Carrying — Sky Battles and Races.”

Mechanician in an apron
The Solbrigs always traveled together during the flying season, sometimes accompanied by their teenage son, Alfred, who thoroughly enjoyed the adventure. The family had worked out a system of assigned tasks comparable to today’s NASCAR pit stop.

Mary’s watchful eye was all the more discerning for the man she loved and the father of her children. No detail was too small for Mary. Before her husband took off, she walked back and forth checking for divots, stones, trash, and unusual dips in the grass and dirt. She always wore an apron over her dress, partially to keep her skirts clean and partially to carry tools in one pocket, dirt in the other.

When she discovered a hole deep enough to cause the slightest jolt to Oscar’s fragile aeroplane wheels, she filled it with dirt and smoothed it over. Her pre-flight checklist included straining gasoline for the Roberts engine through a chamois into a 3-gallon tank, which could keep Oscar aloft for 30 minutes.

After Oscar had cranked up the prop and sat behind the controls of his aeroplane, he nodded to the four men holding on to the struts of the wings. Their job was to hold back the aircraft until the Roberts engine had reached its proper rpms for take-off. The Davenport Sunday Times Democrat paraphrased Mary’s account of Oscar’s take-off procedures, capturing the moment when the Roberts engine spoke to her:

Mrs. Solbrig stepped out in front and critically eyed the makeshift runway. One small hole had been overlooked earlier, so she scurried over and filled it carefully with dirt from her apron pocket. Then, pulling out a handkerchief, she turned to face the plane. The roar of its two-cycle, four-cylinder engine grew louder, and the crowd hushed in anticipation. Listening closely, Mrs. Solbrig heard the motor’s crescendo hit a certain pitch. Now, she could tell from years of experience it was at its highest power output.

Quickly she dropped the white handkerchief, and the men holding the plane let go of its wing. Off it bounced, roaring louder than the crowds. Its three wheels left the ground, and it soared over Mrs. Solbrig’s head and the tops of the trees lining the field.

In another account when Mary and Oscar did not have a crew to hold onto the wings, they devised a system which totally depended upon Mary’s trained ear and her physical strength, both to which Oscar owed his safety:

“The [Solbrigs’] Pusher had a tricycle landing gear, one wheel in front and two behind. Mary Solbrig had a good ear for an airplane engine. She would dig a small hole for the front wheel of the ship, to keep it from moving forward on the engine run-up. Then, with her husband Oscar at the controls, she would take her place at the extreme rear of the plane. Now she would pass a signal to Oscar, who would then accelerate the engine. When maximum engine speed was attained and her ear told her that all was well, she would pull down on the tail of the plane, the front wheel would lift out of the “blocking” hole and Oscar would take off.“

The gift of perfect pitch
All exhibition flying ceased at the onset of WWI. Private aeroplanes were placed in sheds, grounded until the war was over. In 1917 the Solbrigs purchased major parts of a Benoist biplane, assembled and modified it at their home, and added Oscar’s engine of choice, another Roberts. According to Hope, he rarely flew the Benoist in public. “He used to spend all his spare time ... flying it. Of course mama accompanied him. She went every place with him.” Oscar last flew the Benoist in 1921, and Mary, then 52, “retired” as a mechanician. Oscar died in 1941, and the Benoist now hangs in the Historical Building at Des Moines, IA. The disposition of their Curtiss aeroplane is unknown.

Before licensing was required during the 1920s, Mary Solbrig was among America’s first female mechanicians. She listened to the rpms of the Roberts engine with the same discerning ear attuned to the chords of her church organ.

Mary Solbrig, the woman with perfect pitch, died in 1954 at age 85. Her life was long. Her legacy in aviation maintenance is eternal.