Summary remarks on momentum theory
The place of momentum theory is that it gives a broad understanding of the functioning of the rotor and provides basic relationships for the induced velocity created and the power required in producing a thrust to support the helicopter. The actuator disc concept, upon which the theory is based, is most obviously fitted to flight conditions at right angles to its plane, that is to say the hover and vertical flight states we have discussed. Nevertheless further reference to the theory will be made when discussing forward flight (Chapter 5). Momentum theory brings out the importance of disc loading as a gross parameter: it cannot however look into the detail of how the thrust is produced by the rotating blades and what design criteria are to be applied to them. For such information we need additionally a blade element theory, corresponding to aerofoil theory in fixed-wing aerodynamics: to this we shall turn in Chapter
The place of momentum theory is that it gives a broad understanding of the functioning of the rotor and provides basic relationships for the induced velocity created and the power required in producing a thrust to support the helicopter. The actuator disc concept, upon which the theory is based, is most obviously fitted to flight conditions at right angles to its plane, that is to say the hover and vertical flight states we have discussed. Nevertheless further reference to the theory will be made when discussing forward flight (Chapter 5). Momentum theory brings out the importance of disc loading as a gross parameter: it cannot however look into the detail of how the thrust is produced by the rotating blades and what design criteria are to be applied to them. For such information we need additionally a blade element theory, corresponding to aerofoil theory in fixed-wing aerodynamics: to this we shall turn in Chapter
No comments:
Post a Comment