Design Optimization of Sprayer Drone Configuration for Batu Ijo and Birma Shallots

The downwash from the drone sprayer might damage the crops in their growth phase. Therefore, the research aims to design profile of propeller blade, number of propellers, and drone operation mode that will not damage two varieties of shallots, namely Batu Ijo and Birma. The research starts with CFD simulation of comboX6en blade configuration, which required thrust of 200 N to hover and downwash speed in the range of 14 – 22 m/s. Based on this research on the Batu Ijo and Birma shallot leaf’s strength, the aerodynamic simulation of downwash at speed of 22 m/s at slope of 90° from the shallot leaf will lead to failure. Then, blade element theory was used to find the chord and twist distribution that could meet the hover flight thrust with constraining engine power of 870 Watts. The chord and twist distribution were transformed using transformation matrices to construct the airfoil configuration for CFD simulations to obtain the thrust needed with minimum downwash. From the three types of airfoil selected, i.e. NACA 0012, NACA 0015, and NACA 4415, it was found that the acceptable configuration is a NACA 4415, which can produce the required thrust at 66% throttle on hexa-rotor configuration drone with an 8-blade propeller. Thus, based on the operation simulation, the recommended flight height is 2 m from the crop to ensure uniformity of spraying droplets.