Ing Ind - Inf (Mag.)(ord. 270) - BV (469) AERONAUTICAL ENGINEERING - INGEGNERIA AERONAUTICA
097488 - ROTORCRAFT DESIGN
Main goal is to introduce major problems related to preliminary design of a vertical take off aircraft with particular attention to main rotor.
Risultati di apprendimento attesi
Students will be able to evaluate the effect of a change in the main design parameters of a rotor on performance, aeroelastic and aeromechanical stability, flight qualities, vibrations, etc , during the preliminary design pahse of a rotorcraft.
Introduction - Historical background. Classification of vertical take-off vehicles. Helicopter. Hub types: articulated, hingeless and bearingless.
Rotor aerodynamics - Momentum theory in axial flow. Induced power. Blade element theory in axial flight. Figure of merit. Optimal rotor in hovering. Ground effect. Vertical drag. Rotor reference systems. Forces and power in forward flight.
Rigid blade dynamics - Equation of motion of a rigid flapping blade in vacuum. Contribution of aerodynamic forces. Lock number. Floquet theorem. Pitch-flap coupling. Lag and pitch equations of motion. Pitch-flap and flap-lag instabilities. Aeromechanical instabilities.
Performances - Helicopter equations in forward flight. Power required energetic and equilibrium methods. Autorotation. Height-velocity diagram.
Stability and control - Linear equations of motion. Helicopter response to speed, angle of attck and pitch velocity perturbations. Stick fixed longitudinal stability. Automatic stabilization: requirement on control power, sensitivity and damping.
Flexible blade - Equilibrium equations of a rotating blade. Numerical methods for computing rotating frequencies and modes. Dynamic response of a blade. Displacement ans acceleration modes.
Vibrations - Human sensitivity to vibrations. Transmissibility of forces and moments through rotor hub. Passive and active methods for vibration reduction.
Basic knowledge in aerodynamics (lifting line theory) and dynamics (frequency response of a single degree of freedom system) are required.
Modalità di valutazione
Assessment of the preparation is based both on the reports of the homework activities and on the oral exam, aimed to verify the knowledge of the arguments presented during lessons.
- ability of critical judgement of the results
- way of presentation of design results in a technical report
- knowledgle of the assumptions and of the bounds of the numerical methods used
will be considered in final evaluation.
W.Johnson, Rotorcratft Aeromechanics, Editore: Cambridge University Press
A.R.S. Bramwell, Helicopter Dynamics, Editore: Edward Arnold
R.L.Bielawa, Rotary Wing Structural Dynamics and Aeroelasticity, Editore: AIAA Education Series
S.Newmann, The foundations of Helicopter Flight, Editore: Edward Arnold
Copy of slidesBeep
Tipo Forma Didattica
Ore di attività svolte in aula
Ore di studio autonome
Laboratorio Di Progetto
Informazioni in lingua inglese a supporto dell'internazionalizzazione
Insegnamento erogato in lingua
Disponibilità di materiale didattico/slides in lingua inglese
Disponibilità di libri di testo/bibliografia in lingua inglese
Possibilità di sostenere l'esame in lingua inglese