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National Advisory Committee for Aeronautics, Report - Summary Report on the High Speed Characteristics of Six Model Wings Having NACA 65 Series Sections

A summary of the results of wind-tunnel tests to determine
the high-speed aerodynamic characteristics of six model win-gs
having NAG-l 651-series sections is presented in this report.
The 8—percent-thiclc wings were superior to the ZO—percent
and Ifl—percent—thich u'ings from the standpoint of power
economy during lerel flight for hfach numbers above 0.76.
However, airplanes that are tofiy at JIach numbers below 0.76
will gain aerodynamically if the percentage thickness of the
wing and the aspect ratio are. both increased. The lift-curre
slopes for the 8-percent—thiclr wings at 0.85 lIach number were
roughly twice their low-speed calues. The efectireness of a
20-percent-chord flap on the 651-210 wing of aspect ratio 9
decreased rapidly as the Jfach number was raised abore 0.85
indicating probable dificulty in maintaining control by means
of a 20—perc'ent-chord flap on a. wing or tail of this thickness
at these JIach numbers. Dire-recocery flaps tested on the 8—
percent—thiclc wing of aspect ratio ’5’2 reached the maximum
ejectireness at about 0.84 Illach number.

The high-speed aerodynamic characteristics of six thin,
finite-span wings having NACA Girl—series airfoil sections are
summarized and compared in this report. The high-speed
characteristics were obtained from tests made in the Ames
16-foot high-speed wind tunnel. The tests Were made to
obtain. data to aid in the design of airplanes having high
level—flight speeds.

The models were designed and constructed at the Ames
Aeronautical Laboratory. The dimensions of the models
are shown in figure 1, and the coordinates of the various
wing sections are tabulated in table I. Figures 2 and 3 are
photographs showing one of the model wings mounted in
the Ames 16—foot high—speed “and tunnel. All the wings
had NACA 651-series sections, 2.5 to 1 taper ratio, 3° dihe—
dral. and a 10—foot span. The airfoil sections all had 0.2
ideal lift coefficient and a uniform chordwise load distribu-
tion ((1:1) at this lift coefficient. The wing plan forms
were such that the 25-pcrcent—chord lines were unswept.