2.1 Momentum Theory for Hover2.2 Non-dimensionalization2.3 Figure of Merit2.4 Axial Flight2.5 Momentum Theory for Vertical Climb2.6 Modelling the Streamtube2.7 Descent2.8 Wind Tunnel Test Results2.9 Complete Induced-Velocity Curve2.10 Summary Remarks on Momentum Theory2.11 Complexity of Real Wake2.12 Wake Analysis Methods2.13 Ground Effect2.14 BrownoutReferences