Interference effects of longitudinal flat plates on low-drag airfoils Page: 3 of 15
This report is part of the collection entitled: National Advisory Committee for Aeronautics Collection and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
extreme leading-edge roughness on airfoils in the doubt-
ful range (reference 2) indicated that the conservative
range of airfoil design was probably being exceeded. It
war thought, moreover, that airfoils showing a tenden'oy
to break down locally v when the leading edges were rough-
sned might also break down in the presence of other dis-
turbances such as disturbances caused by fuselage and
nacelle interference. The possibility also existed that
the flow over the airfoil of a fully developed turbulent
boundary layer, as at the wing-fuselage juncture, might
be even more effective than leading-edge roughness in
promoting looal flow breakdowns.
The present investigation was accordingly started to
study the effects on typical airfoil sections of an inter-
seating flat plate normal to the span. The lead,ing, edge
of the flat plate was roughened to produce turbulent
boundary layers. The set-up accordingly simulated rea-
sonably well the boundary-layer conditions at the inter-
section of a wing with a large flat-sided fuselage. The
present tests are considered preliminary to more exten-
sive and detailed interference investigations, which will
be conducted when time permits.
METHODS
The arrangement of the airfoils and flat plates is
shown in figures 1 and 2. In some oases the flat plate
was placed off the center line for practical reasons.
The tests were made in the NAGA two-dimenetonal low-
turbulence pressure tunnel by the methods described in
reference 1. The drag coefficients of the airfoil-flat
plate combinations were evaluated by the integration of
results obtained by the wake-survey method at numerous
spanwise stations. The drag of the flat plate supported
from the tunnel wall was measured by the wake-survey
method,
The interference drag coefficient, AQd, was ob-
tained by subtracting from the drag coefficients of the
combination the drag coefficients of the flat plate and
the airfoil section as measured separately, The .inter--
forene drag coefficient, dod, is based on an area
equal to the airfoil ahord squared. The values presented
are for two intereotions represented by the two side of
the flat plate.
Upcoming Pages
Here’s what’s next.
Search Inside
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Abbott, Ira H. Interference effects of longitudinal flat plates on low-drag airfoils, report, November 1942; (https://digital.library.unt.edu/ark:/67531/metadc61370/m1/3/: accessed April 24, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.