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National Advisory Committee for Aeronautics, Technical Notes - Full Scale Wind Tunnel and Flight Tests of a Fairchild 22 Airplane Equipped with External Airfoil Flaps

Fairchild 22 airplane equipped with a wing having external—
airfoil flaps that also perform the functiOn of ailerons.
Lift, drag, and pitching-moment coefficients of the air—
plane with several flap settings and the rolling— and
yawing—moment coefficients with the flaps deflected as
ailerons were measured in the full-scale tunnel with the
horizontal tail surfaces and propeller removed. The ef-
fect of the flaps on the low speed and on the takeuoff and
landing characteristics, the effectiveness of flaps when
used as ailerons, and the forces required to operate them
as ailerons were determined in flight.

The wind—tunnel tests showed that the flaps increased
the maximum lift coefficient of the airplane from 1.51
with the flap in the minimum drag position to 2.12 with
the flap deflected 30° In the flight tests the minimum
speed_ decreased from 46. 8 miles per hour with the flaps up
to 41. 3 miles per hour with the flaps deflected. The re—
quired take~off run to attain a height of 50 feet was re—
duced from 820 to 750 feet and the landing run from a
height of 50 feet was reduced from 930 to 480 feet. The
flaps for this installation gave lateral control that was
not entirely satisfactory; Their rolling action was good
but the adverse yaw resulting from their use was greater
than is considered desirable, and the stick forces required
to operate them increased too rapidly with Speed.
At the request of the Bureau of Aeronautics, Navy De—
partment. the N.A.G.A. is conducting a series of tests of
different types of flapped wings on a Fairchild 22 airplane.

The tests consist of the measurement in the full~scale
wind tunnel of the primary aerodynamic characteristics of
the airplane with each type of flap and the determination
in flight of the take—off, landing, and other characteris—
tics not readily obtained in the wind tunnel. Results
from tests of a Fowler wing and a wing equipped with a Zap
flap are given in references 1 and 2, respectively. The
present paper deals with results of the tests of external~
airfoil flaps that combined the functions of ailerons and
flaps.