One of the Curtis XO-12's issued to the 118th Observation Squadron in the late 1920s. Its rotary engine, excellent for fighter aircraft for its power and ability to steeply climb to high altitudes, proved less satisfactory when used to power a plane which was intended to fly, slower and with less vibration so its manually operated camera could take sharp images. 
From The Air Guard, by Rene Francillon, Aerograph Press, 1983
United States Air Force
1926
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