Modification of Drag and Lift Balance at Analog Wind Tunnel for Identification of Aerodynamic Performance

The development of drag and lift balance aimed to modify and creating a measuring instrument that may be used in the field of aerodynamics or in testing aerodynamic properties. This measurement is in the form of wind speed on an object model such as airfoils, building models and automotive technology. This design uses an open circuit wind tunnel with a low turbulence subsonic type, with a maximum air speed of 30 m/s. The exsisting wind tunnel still uses an analogue measuring instrument which is then modify in a digital arduino-based for drag and lift balance measuring instrument with a drag and lift sensor maximum load of 1kg (v=30m/s) and maximum air speed of 50m/s. The Measuring instrument is calibrated using a 1kg weight test equipment for testing with the test object model (spherical, hemispherical, cylindrical, cube) and three types of airfoil models. The test results are in the form of drag coefficient (Cd) and lift coefficient (CL). The coefficient of drag is greatest in the cube shape and lowest in the sphere, but will decrease in value at a speed of 20 m/s. In the airfoil, the values ​​of Cd and CL have the same trend with the literature with an uncertainty value of less than 10%. The value of CL / Cd will increase as the angle of attack increases, but can very significantly depending on the fluid, airfoil, and aircraft type.