Chapter 4 Forces and Moments Beard Mc Lain

Chapter 4 Forces and Moments Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 1

Equations of Motion from Chap 3 Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 2

External Forces and Moments Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 3

Gravity Force Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 4

Airfoil Pressure Distribution ure s s re p c w lo be ti a t s above static pressure Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 5

Aerodynamic Approximation Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 6

Control Surfaces - Conventional Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 7

Control Surfaces – V-tail Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 8

Control Surfaces – Flying Wing Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 9

Aircraft Dynamics • Aircraft dynamics and aerodynamics are commonly separated into two groups: • Longitudinal • Up-down, pitch plane, pitching motions • Lateral-directional • Side-to-side, turning motions (roll and yaw) Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 10

Longitudinal Aerodynamics Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 11

Aerodynamic Approximation stability derivatives control derivative Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 12

Linear Aerodynamic Model Linear aerodynamic model is valid for small angles of attack – flow remains attached over wing Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 13

Nonlinear Aerodynamics – Stall Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 14

Nonlinear Lift Model (linear model) (flat plate model) Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 15

Nonlinear Aerodynamic Model linear model flat-plate model blending function Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 16

Blending Function Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 17

Nonlinear Aerodynamic Model Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 18

Drag vs. Angle of Attack parasitic drag induced drag parasitic drag: profile drag of wing, friction and pressure drag of tail surfaces, fuselage, landing gear, etc. induced drag: “drag due to lift” linear model incorrect for negative angles of attack Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 19

Linear Lift and Drag Models Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 20

Longitudinal Forces – Body Frame Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 21

Pitching Moment Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 22

Lateral Aerodynamics Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 23

Lateral Aerodynamics Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 24

Aerodynamic Coefficients Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 25

Longitudinal Static Stability Derivative Center of Pressure is the point where there is no moment due to aerodynamic forces. The lift and drag forces act at this point. Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 26

Roll Static Stability Derivative (view from the tail) Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 27

Yaw Static Stability Derivative Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 28

Aerodynamic Coefficients Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 29

Propeller Thrust and Torque Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 30

Propeller Thrust and Torque Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 31

Propeller Thrust and Torque Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 32

Propeller Thrust and Torque Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 33

Propeller Thrust and Torque Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 34

Propeller Thrust and Torque Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 35

Wind Model Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 36

Wind Model Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 37

Dryden Gust Model Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 38

Transfer Function Implementation Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 39

Propeller Thrust and Torque Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 40

Adding in the Effects of Wind Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 41

Project 4 Beard & Mc. Lain, “Small Unmanned Aircraft, ” Princeton University Press, 2012, Chapter 4: Slide 42