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naca-tn-1680

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National Advisory Committee for Aeronautics, Technical Notes - Divergence of Swept Wings

naca-tn-1680-divergence-of-swept-wings-1

An analysis of the divergence of swept untapered and tapered wings
with stiffnesses varying as the fourth power of the chord has been
performed and checked experimentally. The results are presented in a
set of charts and approximate formulas suitable for quick estimates of
the divergence dynamic pressure and hence the divergence speed.

These results indicate that the divergence speed drops rapidly
as sweepforward increases to about #00 but that wings with moderate or
large sweepback cannot diverge. The location of the elastic axis is
found to affect the divergence speed most at low angles of sweep, where
movement of the elastic axis forward (or the aerodynamic center aft)
raises the divergence speed. The effect of wing taper is to increase
the divergence speed of essentially unswept wings and to decrease the
divergence speed of wings with moderate and large angles of sweep in
the case of the prescribed stiffness variation. Evidence is presented
to indicate that these effects may not be‘observed for actual stiffness
variations, in which cases a more refined analysis must be resorted to.

The-emphasis on the use of sweptback or sweptforward wings for
high-speed flight has created widespread interest in the aeroelastic
behavior of swept wings. The present paper is concerned with the
theoretical determination.of one of the most fundamental aeroelastic
parameters, the wing divergence speed.

The divergence of wings or tail surfaces is an instability
phenomenon which results from the interaction of aerodynamic and
structural forces. If a wing or tail is given_a deflection of
arbitrary magnitude, the aerodynamic forces often act in such a way
as to increase the given deflection, whereas the structural forces
always tend to decrease the deflection. Since the aerodynamic forces
increase with the flying speed, whereas the structural forces are
independent of it, a speed will often exist at which the two sets of
forces are exactly in balance, so that they tend to maintain the given
deflection.

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naca-tn-1680

  • Version
  • 175 Downloads
  • 1.27 MB File Size
  • 1 File Count
  • December 4, 2016 Create Date
  • December 4, 2016 Last Updated
Scroll for Details

National Advisory Committee for Aeronautics, Technical Notes - Divergence of Swept Wings

naca-tn-1680-divergence-of-swept-wings-1

An analysis of the divergence of swept untapered and tapered wings
with stiffnesses varying as the fourth power of the chord has been
performed and checked experimentally. The results are presented in a
set of charts and approximate formulas suitable for quick estimates of
the divergence dynamic pressure and hence the divergence speed.

These results indicate that the divergence speed drops rapidly
as sweepforward increases to about #00 but that wings with moderate or
large sweepback cannot diverge. The location of the elastic axis is
found to affect the divergence speed most at low angles of sweep, where
movement of the elastic axis forward (or the aerodynamic center aft)
raises the divergence speed. The effect of wing taper is to increase
the divergence speed of essentially unswept wings and to decrease the
divergence speed of wings with moderate and large angles of sweep in
the case of the prescribed stiffness variation. Evidence is presented
to indicate that these effects may not be‘observed for actual stiffness
variations, in which cases a more refined analysis must be resorted to.

The-emphasis on the use of sweptback or sweptforward wings for
high-speed flight has created widespread interest in the aeroelastic
behavior of swept wings. The present paper is concerned with the
theoretical determination.of one of the most fundamental aeroelastic
parameters, the wing divergence speed.

The divergence of wings or tail surfaces is an instability
phenomenon which results from the interaction of aerodynamic and
structural forces. If a wing or tail is given_a deflection of
arbitrary magnitude, the aerodynamic forces often act in such a way
as to increase the given deflection, whereas the structural forces
always tend to decrease the deflection. Since the aerodynamic forces
increase with the flying speed, whereas the structural forces are
independent of it, a speed will often exist at which the two sets of
forces are exactly in balance, so that they tend to maintain the given
deflection.

FileAction
naca-tn-1680 Divergence of Swept Wings.pdfDownload 
17,005 Documents in our Technical Library
2450037 Total Downloads

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Newest Additions

NASA-RP-1060 Subsonic Aircraft: Evolution and the Matching of Size to Performance
NASA-RP-1060 Subsonic Aircraft: Evolution and the Matching of Size to Performance
AA-CP-20212-001
AA-CP-20212-001
ADPO10769 Occurrence of Corrosion in Airframes
The purpose of this lecture is to provide an overview ...
MIL-STD-1759 Rivets and Rivet Type Fasteners Preferred for Design
The purpose of this book form standard is to provide ...
MIL-STD-810G Environmental Engineering Considerations and Laboratory Tests
This standard contains materiel acquisition program planning and engineering direction ...