Editing Hyper engine (section)

===Hyper No.2===

A second cylinder was added to Hyper No. 1 to make a horizontal opposed engine for evaluation of an horizontal opposed 12-cylinder engine. After running the modified engine with different combinations of cylinder bore and stroke, it was found that the high coolant temperature required to maintain the required output was impractical.  A third high-performance single-cylinder engine was then constructed with lower operating parameters.  This engine was designated "Hyper No. 2", and became the test bed for developing the cylinders that would become the O-1430-1.<ref name="Balzer28"/>