Prandtl's Pitot-static tube, old and new form. In the early years of the 1910s, L. Prandtl changed the shape of the nose of its antenna so that it was easier to reproduce. This nose went from a 3D half-body of Rankine (which was theoretically calculable) to a simpler hemisphere-cylindrical shape. According to: PITOT-STATIC TUBES FOR DETERMINING THE VELOCITY OF AIR, KUMBRUCH H., 1925, NACA Technical Memorendum N° 303 <a rel="nofollow" class="external autonumber" href="https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930086911.pdf">[2]</a>
<a href="//commons.wikimedia.org/wiki/User:Bernard_de_Go_Mars" title="User:Bernard de Go Mars">Bernard de Go Mars</a>
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<span class="int-own-work" lang="en">Own work</span>