Adaptive proprotors as applied to convertible MAVs

Peng Lv (1) , Fazila Mohd Zawawi (1, 2) , Emmanuel Bénard (1) , Sebastien Prothin (1) , Jean-Marc Moschetta (1) , Joseph Morlier (2)

1 DAEP - Département Aérodynamique Energétique et Propulsion
2 ICA - Institut Clément Ader

A passive twist control is considered as an adaptive way to maximize the overall efficiency of a proprotor developed for convertible Micro Air Vehicles (MAV). Incorporated into a database of airfoil characteristics, Blade Element Momentum Theory (BEMT) is implemented to predict the performance of proprotors at low Reynolds numbers. Using this model, it is found that low twist allows for efficient hovering while high twist helps to forward flight. The Centrifugal Force Induced Twist (CFIT) concept is proposed to realize the required torsion of proprotor between hover and forward flight. Tip mass is used to provide the nose-down twisting moment by centrifugal force and stabilize the flexible blade. Classical Lamination Theory (CLT) is employed to estimate the torsion behavior of glass/epoxy laminate blade and to study the feasibility of CFIT concept. The results indicate that the predicted torsion of CFIT blade is of the same level with required deformation. The laminate blades were tested in hover and forward flight modes, with deformations measured by Laser Displacement Sensor (LDS). In rotor mode, the laminate blade can generate approximately -9◦ torsion at blade tip rotating at 1,300 RPM. By contrast, at 800 RPM and inflow velocity 8m/s, it is capable of providing around -5◦ torsion at blade tip in propeller mode.

Mots clés: Adaptive proprotors; Composite laminate blades; Laser Displacement Sensor; Convertible MAVs

Domaines: Matériaux

Peng Lv, Fazila Mohd Zawawi, Emmanuel Bénard, Sebastien Prothin, Jean-Marc Moschetta, et al.. Adaptive proprotors as applied to convertible MAVs. International Micro Air Vehicle Conference and Flight Competition (IMAV2013), Sep 2013, Toulouse, France. pp.0. ⟨hal-01851618⟩