Experimental studies of propeller induced flow over typical micro air vehicle - AIAA 2013-0060

An experimental study has been carried out to explore the effect of propeller induced slipstream on the flow field of a fixed wing micro air vehicle (MAV). Tests were conducted at freestream velocity of 10m/s, corresponding to Reynolds number based on root chord of about 160000. Flow pattern on the surface of MAV planform with propeller-on and off condition was captured using oil flow visualization at four angles of incidence. Mean flow field on the MAV planform at four chordwise planes with propeller-on and off condition were measured using stereo PIV technique at angle of incidence of 24°. Little difference has been seen on the oil flow pattern at 10° and 15° angle of incidence between propeller-off and on condition. Small asymmetry in the flow topology was observe at 20° angle of incidence. Significant difference in flow field was observed at 24° between propeller-on and off condition. The induced slipstream from the propeller makes the flow well attached over the wing planform

Preliminary wind tunnel studies on Micro-Air Vehicles

A preliminary wind tunnel studies were carried out in the 0.55m low speed tunnel on the Micro Air Vehicle configurations which have been test flown. The flown MAV's vary both in planform and airfoil geometry. A 3-component internal strain gage balance was used to measure the aerodynamic data. The tests were carried out at a freestream velocity of 12 m/s and at angle of attack varying from -4 deg to 24 deg in 4 deg steps. A comparison of the aerodynamic characteristics of the airframe (wing and fuselage) was made in terms of lift slope, stall angle, minimum drag, aerodynamic efficiency (L/D) and the pitching momebt stability. Error ananlysis was made and the results were discussed. Detailed 6-component measurements, control surface effects, propelled model tests are planned in the second phase

Interaction of two micro-propellers in coplanar and coaxial arrangement for UAV application

In the present work, we have focused on the understanding of the effect of gap between micro propellers in coplanar and in coaxial arrangements on the thrust generation experimentally. In a way it’s a preliminary optimization of the spacing and placement of the micro propellers in a multirotor UAV system. APC 12-inch diameter (D) (12X8 E) and Master air screw (MAS) 11-inch diameter (11X6) propellers each 2 in numbers were considered in the study. A static testing rig was built with a provision to mount the propellers in coplanar and in coaxial arrangements. A thrust was measured using a single component load cell. Parameters like current consumption by BLDC motors and propeller RPM were also monitored. For coplanar arrangement, there is no influence of gap (G) between the propellers on the coefficient of thrust (CT). However, for G/D<0.2 random variation in CT is observed. Similarly, for propellers in coaxial arrangement, for smaller gap between the propellers along the axis is found to generate higher thrust. This optimization of the gap between the propellers may be lead to a compact multi-rotor UAV system having higher payload carrying capacity or higher enduranc