• Version
• 202 Downloads
• 2.85 MB File Size
• 1 File Count
• November 2, 2016 Create Date
• November 2, 2016 Last Updated

National Advisory Committee for Aeronautics, Report - Effects of Wing Position and Fuselage Size on the Low Speed Static and Rolling Stability Characteristics of a Delta Wing Model

An investigation was made to determine the efiects of wing
position and fuselage size on the low-speed static and rolling
stability characteristics of airplane models having a triangular
wing and vertical tail surfaces.

For the longitudinal—stability case, the results indicated that,
for all wing positions, as the fuselage size was increased the
maximum lift coefiicient decreased. Also, for a given fuselage
size, the maximum lift coefi‘lcient increased as the wing position
was changed from low to high.

For the lateral-stability case, the results indicated an increase
in the vertical-tail lift-curve slope as well as an increase in the
efective dihedral with an increase in fuselage size. Both these
ejects could be calculated with good accuracy by using available
theory. As indicated by both available theory and results of
previous investigations, the efiective dihedral at low angles of
attack caused by wing-fuselage interference changed sign as the
wing position was changed from low to high. Moving the wing
from the low to the high position caused the vertical-tail con-
tribution to the directional stability to decrease at low and
moderate angles of attack. At high angles of attack, all the
configurations investigated became directionally unstable. H ow-
ever, the loquing—largejuselage (fineness-ration? configuration
maintained directional stability to an angle of attack above
that which corresponds to maximum lift.

For the rolling-stability case, the results generally indicated
very little eject of both wing position and fuselage size.

In recent years, the accent on high-speed flight has led to
many changes in the design of the major components of
airplanes. The incorporation of large amounts of sweepback
in the wing and tail surfaces, use of low aspect ratio, changes
in wing and horizontal-tail positions relative to the fuselage,
and changes in the fuselage shape are but a few of the many
changes that have led to the consideration of some configura-
tions for which design information regarding stability
characteristics is not available. In order to provide general
information which would aid the designer of present-day
airplanes, a series of investigations is being conducted in
the Langley stability tunnel on models having various
interchangeable parts. Some of these investigations have
resulted in the development of methods for estimating the
various stability derivatives and also have provided infor-
mation with which to check the validity of existing theories.