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National Advisory Committee for Aeronautics, Technical Notes - Investigation of Effect of Span, Spanwise Location, and Chordwise Location of Spoilers on Lateral Control Characteristics of a Tapered Wing

An investigation was made of the effect of span,
spam-rise location, and chordwise location of spoilers on the
lateral control characteristics, of- an unflapped semispan wing
equipped with a simple spoiler having a projection 5 percent of
the chord. In deteitlining the effect of spoiler span and spam-rise
location, the spoiler was mounted. at the 70—pement—chord station
with the spoiler span increasing from 10 percent of the semispan
to 100 percent of the semispan. The chordwise investigation
involved. moving a 50—perceILt-semispan spoiler from the 50—percent—
chord. station'to the 80—percent-ohord station. _

Curves are presented showing the variation of rolling—moment
and yawing—moment effectiveness with spoiler span. The results
indicated that the variation of rolling-moment effectiveness with
spoiler span showed a trend similar to that of ailerons for a
geometrically similar wing. This similarity suggests the possibility
of employing aileron design data in the preliminary design. of
spoilers at low angles of attack. For a more exact estimation of
the spoiler rolling moment expected at large angles of attack,
however, consideration should. be given to the change in effectiveness
with angle of attack. The spemrise yawi ng-moment effectiveness for
ailerons and. spoilers showed. the same trend. with spanwise location;
but ”because the spoilers gave favorable yawing moments, the spoiler
data differed. in sign- from the aileron data. When the 50—percen’o—
semispen spoiler was moved rearward. from the 50—percent—ohord. station
to the 80—percent-chord station on the unflapped wing, both the
rolling—moment and yawing-moment coefficients were reduced.

The use of spoilers as lateral—control devices has long “been
5. 811.133th of research for the National Advisory Comittee’ for
Aeronautics. Some notable merits of spoilers, such as control at
high angles of attack, fewerable yawing moments, and the practicable
use of full—span flaps with spoiler arrangements, have been known
for some time. In addition, it has been found that spoilers
generally provide greater rolling moments when fullwspan flaps are
deflected, particularly when the spoiler mtves through an opening
(spoiler slot) in the wing. These and other aerodynamic character—
istics of spoilers, such as spoiler lag, have been studied and
presented in numerous papers.