The aerofoil model HM 170.21 has an adjustable slat and an adjustable slot flap on the rear. On the slat it is possible to vary the separation to the leading edge of the base profile; the slot flap can be adjusted in angle and separation. The slot flap can be detached.
Together with the slat, the base profile of the aerofoil corresponds to the symmetrical profile NACA 0015. To avoid secondary flows, the aerofoil is fitted with circular covering discs.
The aerofoil is placed in the force sensor, this indicates the drag force as a measured value in flow around bodies.