• Version
• 89 Downloads
• 898.73 KB File Size
• 1 File Count
• November 25, 2016 Create Date
• November 25, 2016 Last Updated

National Advisory Committee for Aeronautics, Technical Notes - Charts for Determining the Pitching Moment of Tapered Wings with Sweepback and Twist

This report presents a convenient method for calcu-
lating the pitching—moment characteristics of tapered wings
with sweepback and twist. The method is based on the fact
that the pitching-moment characteristics of a wing may be
specified by giving the value of the_pitching moment at
zero lift and the location of the axis about which the mo-
ment is constant. Data for calculating these characteris—_
tics are presented by curves which apply to wings having a
linear distribution of twist along the span and which cover
a large range of aspect ratios. The curves are given for
wings having straight taper and distorted elliptical plan
for-as. The characteristics .of wings of other shapes may be
determined by interpolation.

The use of tapered wings on airplanes has led to the
development of methods of calculating the characteristics
of such wings from the known characteristics of'the sec—
tions. Two methods for calculating the pitching momept of:
tapered wings are given in references 1 and 2. In reference
1, formulas are given which apply to wings without twist and
which have a lift distribution closely approaching an 61-
lipse._ Factors for use in the formulas are giVen for a few
plan forms and a few variations of section pitching moment
across the span. In reference 2, formulas are given for _
straight—taper wings with twist and_with constant section
moment across the span. Factors for use in the formulas are
tabulated for a feW'aspect ratios and taper ratios. The in—
formation given in reference 1 is limited in scope, and that
of reference 2 is presented in such form thatflit cannot be
readily applied by airplane designers.

The purpose of this report is to present a method by
which airplane designers,mayLreadilyfhhlchlate the pitch—
ing—moment characteristics_of tapered wings with sweep—
back and twist. Formulas are given for Calculating the
pitchingrmoment:characteristics.and fnntors'for use in the
formulas are presented on charts. The data on the charts
are given for-h large range of aspect ratios and apply to
wings having a linear distribution of twist along the span.
Curves for wings haVing straight taper and distorted ellip—
tical plan forms are presented in a form which facilitates
the determination of the characteristics of wings of other
shapes.