He set himself anew to find the practical conditions of equilibrium and of horizontal flight.

His experiments convinced him that "mechanical sustenation of heavy bodies in the air, combined with very great speeds, is not only possible, but within the reach of mechanical means we actually possess." After many experiments with new models Langley at length fashioned a steam-driven machine which would fly horizontally.

It weighed about thirty pounds; it was some sixteen feet in length, with two sets of wings, the pair in front measuring forty feet from tip to tip.

On May 6, 1896, this model was launched over the Potomac River.

It flew half a mile in a minute and a half.