WOLFRAM SYSTEM MODELER

Ailerons

Contribution from ailerons to aerodynamic forces

Diagram

Wolfram Language

In[1]:=
SystemModel["Aircraft.Physical.FixedWing.Parts.ControlSurfaces.Components.Ailerons"]
Out[1]:=

Information

This model calculates the aerodynamic forces due to aileron deflection. All parameters, including the ailerons specific parameters, are propagated to this model from the AircraftBase model, and therefore their values should not be changed here but only in the complete aircraft model. Additionally, the variables of the global flight conditions are propagated here from the AircraftBase model inside the flightData record. The mass properties of the ailerons (if the weight estimation method is used) are included in the equations in the WingBody component.

All forces in this model act on the supposed aerodynamic center of the ailerons, which is at quarter chord at half of the aileron span length. The position of the ailerons with respect to the fuselage reference point is solved based on the given y coordinates of the aileron root and tip (yAilRoot and yAilTp) and the main wing geometry. The equations to estimate the aerodynamic center location as well as any other estimated ailerons parameter can be bypassed by entering the known value in the Ailerons group in the Derived Properties parameter tab in the AircraftBase model.

The magnitudes of the aerodynamic forces acting along the body x and z axes due to ailerons deflection are solved by using the lateral control coefficients for yaw moment due to ailerons deflection (CnDeltaAil) and roll moment due to ailerons deflection (ClDeltaAil), respectively. The derivation of the normalized lateral control coefficients CnDeltaAil and ClDeltaAil, and their conversions into forces by multiplying them by correct factors are performed according to the method presented by Nelson [1]. The empirical factor kCnDeltaAil (KC,n,δa) used for solving CnDeltaAil, is calculated based on a formula presented in section 3.3.4 in Reference [2].

The aerodynamic forces due to ailerons deflection are applied with opposite signs in each side of the main wing as the ailerons are set to always deflect symmetrically but in opposite directions. The signs follow the sign convention of control surface deflections presented in ControlSurfaces.Conventional.

References

[1]  Nelson, R. C. (1998) Flight Stability and Automatic Control2nd ed. McGraw-Hill.
      Available at: http://home.eng.iastate.edu/~shermanp/AERE355/lectures/Flight_Stability_and_Automatic_Control_N.pdf.

[2]  Erä-Esko, N. (2022). "Development and Use of System Modeler 6DOF Flight Mechanics Model in Aircraft Conceptual Design."
      Available atmodelica://Aircraft/Resources/Documents/EraeEskoThesis.pdf.

Parameters (25)

weightEst

Value:

Type: Boolean

Description: true, if weight estimation method is used for masses, center of mass location and inertia tensor

xCMdry

Value:

Type: Length (m)

Description: Aircraft center of mass x-coordinate w.r.t. fuselage reference point (with total mass for electric aircraft and gliders, positive x-axis towards nose)

wFus

Value:

Type: Length (m)

Description: Fuselage maximum width

bWing

Value:

Type: Length (m)

Description: Main wing span

cWingRoot

Value:

Type: Length (m)

Description: Main wing root chord (where wing intersects with fuselage)

xWingRootLE

Value:

Type: Length (m)

Description: Main wing root leading edge x-coordinate w.r.t. fuselage reference point (positive x-axis towards nose)

zWingRootLE

Value:

Type: Length (m)

Description: Main wing root leading edge z-coordinate w.r.t. fuselage reference point (positive z-axis towards ground)

lambdaWing

Value:

Type: Angle (rad)

Description: Main wing sweep angle at 1/4 chord

gammaWing

Value:

Type: Angle (rad)

Description: Main wing dihedral angle

iWing

Value:

Type: Angle (rad)

Description: Main wing incidence angle

SrefWing

Value:

Type: Area (m²)

Description: Main wing reference area

cWingMean

Value:

Type: Length (m)

Description: Main wing mean chord length

yWingAC

Value:

Type: Length (m)

Description: Main wing aerodynamic center from fuselage centerline (y-coordinate w.r.t. fuselage centerline of mean chord)

lambdaWingLE

Value:

Type: Angle (rad)

Description: Main wing leading edge sweep angle

lambdaWingTE

Value:

Type: Angle (rad)

Description: Main wing trailing edge sweep angle

cAil

Value:

Type: Length (m)

Description: Aileron average chord

yAilRoot

Value:

Type: Length (m)

Description: Aileron root y-coordinate w.r.t. fuselage centerline

yAilTip

Value:

Type: Length (m)

Description: Aileron tip y-coordinate w.r.t. fuselage centerline

cAilWingRoot

Value:

Type: Length (m)

Description: Local main wing chord at aileron root

cAilWingTip

Value:

Type: Length (m)

Description: Local main wing chord at aileron tip

yAilAC

Value:

Type: Length (m)

Description: Aileron aerodynamic center y-coordinate w.r.t. fuselage centerline

kCnDeltaAil

Value:

Type: Real

Description: Empirical factor for the yaw moment derivative due to ailerons

tauAil

Value:

Type: Real

Description: Aileron effectiveness parameter

deltaAilMax

Value:

Type: Angle (rad)

Description: Maximum aileron deflection

CADshapes

Value:

Type: Boolean

Description: true, if external CAD files are used for animation

Inputs (1)

flightData

Type: FlightData

Description: Global flight data variables

Connectors (4)

aircraftRP

Type: Frame_b

Description: Connector to aircraft reference point

deltaAilCmd

Type: RealInput

Description: Ailerons deflection command

uLiftAC

Type: RealInput

Description: Total lift force

uCLalphaWingbody

Type: RealInput

Description: Change in lift coefficient of the wing-body due to alpha

Components (14)

flightData

Type: FlightData

Description: Global flight data variables

rightAilAerodForces

Type: WorldForce

Description: Aerodynamic forces from right aileron

leftAilAerodForces

Type: WorldForce

Description: Aerodynamic forces from left aileron

aileronDynamics

Type: CriticalDamping

Description: Simplified model of the aileron actuator dynamics

deltaAilLimiter

Type: Limiter

Description: Limits aileron deflection to its assigned limits

translWing

Type: FixedTranslation

Description: Position of the main wing root quarter chord (inside fuselage) w.r.t fuselage reference point

rotRightWing

Type: FixedRotation

Description: Rotation of right wing around dihedral and wing incidence angle

rotLeftWing

Type: FixedRotation

Description: Rotation of left wing around dihedral and wing incidence angle

rotRightAilForces

Type: FixedRotation

Description: Rotation of aerodynamic forces acting on right aileron around dihedral and wing incidence angle

rotLeftAilForces

Type: FixedRotation

Description: Rotation of aerodynamic forces acting on left aileron around dihedral and wing incidence angle

translRightAilWing

Type: FixedTranslation

Description: Position of right aileron w.r.t. wing root quarter chord (inside fuselage)

translLeftAilWing

Type: FixedTranslation

Description: Position of left aileron w.r.t. wing root quarter chord (inside fuselage)

rightAilShape

Type: FixedShape

Description: Visualization of right aileron

leftAilShape

Type: FixedShape

Description: Visualization of left aileron

Used in Components (1)

Conventional

Aircraft.Physical.FixedWing.Parts.ControlSurfaces

Model of system of surfaces in conventional wing configuration