The most common aircraft used after the First World War was the
Curtiss JN-4, which was powered by the Curtiss OX 5: the
dominant engine used in aircraft in the 1920s. With its 90 horse
power capacity, it was not only used in JN-4 aircraft like
The City of Edmonton, but also
in planes such as the Travel Air 2000, Waco 9 and 10.
The Curtiss OX 5 engine was an advanced version of the
earlier Curtiss O engine that was used in 1911. The first of the
OX engines was developed in 1912, but the war years saw ongoing
improvements to these engines until they were highly regarded as
reliable, effective aircraft engines.