Patents by Inventor John P. Stack

John P. Stack has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method and apparatus for detecting laminar flow separation and reattachment
    Patent number: 4936146
    Abstract: The invention is a method and apparatus for simultaneously detecting laminar separation and reattachment of a fluid stream such as an airstream from and to the upper surface of an airfoil 22 by simultaneously sensing and comparing a plurality of output signals S, each representing the dynamic shear stress at one of an equal number of sensors 27 spaced along a straight line on the surface of the airfoil 22 that extends parallel to the airstream. The output signals S are simultaneously compared to detect the sensors across which a reversal in phase of said output signal S occurs, said detected sensors being in the region of laminar separation or reattachment.
    Type: Grant
    Filed: May 4, 1989
    Date of Patent: June 26, 1990
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: John P. Stack, Sivaramakrishnan M. Mangalam
  • Method and apparatus for detecting laminar flow separation and reattachment
    Patent number: 4848153
    Abstract: The invention is a method and apparatus for simultaneously detecting laminar separation and reattachment of a fluid stream such as an airstream from and to the upper surface of an airfoil 22 by simultaneously sensing and comparing a plurality of output signals S, each representing the dynamic shear stress at one of an equal number of sensors 27 spaced along a straight line on the surface of the airfoil 22 that extends parallel to the airstream. The output signals S are simultaneously compared to detect the sensors across which a reversal in phase of said output signal S occurs, said detected sensors being in the region of laminar separation or reattachement.
    Type: Grant
    Filed: June 7, 1988
    Date of Patent: July 18, 1989
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: John P. Stack, Sivaramakrishnan M. Mangalam
  • Porous plug for reducing orifice induced pressure error in airfoils
    Patent number: 4770032
    Abstract: A porous plug (10) is provided for the reduction or elimination of positive error caused by orifice (20) during static pressure measurements of airfoil (14). The porous plug (10) is press fitted into orifice (20), thereby preventing error caused either by fluid flow (30) turning into the exposed orifice (20) or by fluid flow (30) stagnating at the downstream edge (21) of orifice (20). In addition, porous plug (10) is flushed with the outer surface of airfoil (14), as by filing and polishing, to provide a smooth surface which alleviates error caused by imperfections in orifice (20). Porous plug (10) is preferably made of sintered metal, which allows air to pass through the pores, so that static pressure measurements can be made by remote transducers (not shown).
    Type: Grant
    Filed: February 5, 1987
    Date of Patent: September 13, 1988
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Elizabeth B. Plentovich, Blair B. Gloss, John W. Eves, John P. Stack