The Engine Whisperer

Mary Heidenreich Solbrig, Mechanician (1869-1954)

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.

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