Langley, S. P. (Samuel Pierpont), 1834-1906 · Washington, Smithsonian institution · leaf 25
olve no (theoretical) expenditure of energy, even although the plane possess inertia. "We see that this plane would rise indefinitely by the action of the wind in alternate directions. The disposition of the wind which is here supposed to cause the plane to rise, appears at first sight an… … ri^.2. Figure 2 shows the wind blowing in one constant direction, but alternately at two widely varying velocities, or rather (in the extreme case supposed in illustj-a-
Winds · Aeronautics
Internet Archive · Cornell University Library · Public domain (published before 1931). Free to use for anything.
