File Size694.84 KB
Tags   Aerofoils     Drag     NACA     Research Memorandum  
naca-rm-l6k08c Drag Measurements at Transonic Speeds of NACA 65-009 Airfoils Mounted on a Freely Falling Body to Determine the Effects of Sweep back and Aspect Ratio.pdfDownload 

National Advisory Committee for Aeronautics, Research Memorandum - Drag Measurements at Transonic Speeds of NACA 65-009 Airfoils Mounted on a Freely Falling Body to Determine the Effects of Sweep back and Aspect Ratio

Drag measurements at transonic speeds on rectangular
airfoils and on airfoils swept back 45° are reported.
These airfoils,which were mounted on cylindrical test
bodies,are part of a series being tested in free drops
from high altitude to determine the effect of variation
of basic airfoil parameters on airfoil drag characteristics
at transfinic speeds. These rectangular and swept-back
airfoils had the same span, airfoil section (NACA 65-009),
and chord perpendicular to the leading edge. The tests
were made to compare the drag of rectangular and swept-
back airfoils at a higher aspect ratio than had been used
in a similar comparison reported previously.

The results showed that the drag of the swept—back
airfoil was less than 0.15 that of the rectangular airfoil
at a Mach number of 1.00 and less than 0.50 that of the
rectangular airfoil at a Mach number of 1.17.

A comparison of these swept—back airfoils with
similar airfoils of lower aspect ratio previously tested
by the same method indicated that in the investigated
speed range reduction in aspect ratio results in increased
drag. In the highest part of the investigated speed range,
however, the drag coefficient of the high~a3pect—ratio
swept-back airfoils showed a tendency to approach that of
the lower—aspect-ratio swept—back airfoils. A similar
oomph ison for the rectangular airfoils showed

that delay in the drag rise and a reduction in drag at f
supercri.tical speeds can be realized through reduction a
in sepect ratio.

A serious limitation on practical flight in the
transcnic-speed range results from the large abrupt
increases in drag of conventional_airplane_configurations
as schic Speed is approached. Because of the imporu
tance of this problem, a series of tests is being conducted
at the Lansley Memorial Aeronautical Laboratory of the
NASA to determine aerodynamic shapes and cenfigurationsv,
that have a minimum of drag at transcnic speeds. In these
tests, data are telemetered from special test configurations
during free fall from high altitude. Previous tests in
which this method was employed were reported in references 1
and 2.

The object of the present tests was to compare
the drag of rectangular and swept-back airfoils at a higher
aspect ratio than had been a similar comparison
reported in reference 2,For the tests reported herein drag
measurements were made on rectangular airfoils and on airfoils having
45° sweepback. These airfoils insorncrated NACA 65-009
sections of equal chord perpendicular to the leading edge
and differed from the airfoils of'reference"2 only by an
increase in even. The subscript 1 has heed deleted from
the designation of NACA-S—series airfoils with thickness
ratios less than 0.12 of the chord." The airfoil designated
65-009'in the present paper, therefore, is the airfoil
section designated 651-009 in reference 2.

Have A Comment On This Article? Post It Here.

Comments are moderated and will not be published until approved. Your email address will be kept confidential. Please review our Comment Policy before posting your comment.


Microsoft Excel Spreadsheets

FREE ANALYSIS SPREADSHEETS 3 Over the last 10 years we have developed hundreds of spreadsheet tools to help us with our structural analysis work. We have made these available through the Abbott Aerospace web site and the XL Viking project. We have now brought them into the technical library. They have been updated, improved and the collection has been expanded to cover more analysis methods than ever before.

The XL-Viking Add-In for Excel

XL-Viking 2 We created the XL-Viking Excel add-in to satisfy our own need to make Excel a better engineering tool. XL-Viking shows your Excel Formula in a way that makes sense and brings essential new functionality to Microsoft Excel by providing an additional user interface and easy to use functions.

The Indispensable Tool For Engineers, Mathematicians, Scientists, Accountants and Teaching Professionals!


Technical Papers & Reports

This is our collection of public domain references. All of the material we make available has been placed in the public domain by the authors/owners. If you believe this is not the case and any of the library material is not in the public domain please let us know. If you have any reference material that you would like to see included in the library we would love to hear from you.

Market Analysis and Market Information

Our newest addition to the library is an on-going series of articles on the aircraft and aerospace market. These are part quantitative and part qualitative and introduce a new aspect to the competencies within Abbott Aerospace.