enginePositionType

An engine position installs an engine at one place of the model, usually under a pylon. The engine itself is defined once in vehicles/engines (engineType), with its nacelle, geometry and performance; the position references it by <engineUID> and states where it is installed. Several positions may reference the same engine, e.g. the inner and the outer engines of a four-engine aircraft.

Placement

<transformation> places the engine coordinate system in the coordinate system of the component named in <parentUID>. The engine coordinate system has its origin in the center of the fan plane, its x-axis along the engine axis to the rear and its z-axis upwards (engineGeometryType). Like every component with a parent, the engine follows the translation of its parent but neither its rotation nor its scaling (transformationType).

The transformation acts on the geometry only. Thrust, mass and performance maps remain those of the engine definition, also where the transformation scales the engine; an engine of another size is defined as another engine.

Symmetry

Without @symmetry, an engine position takes the symmetry of its parent (section 7.1 of cpacsType): an engine under a pylon of a wing with symmetry="x-z-plane" is installed on both sides of the aircraft. With @symmetry, the position sets a symmetry of its own; none installs the engine once, even if its parent is mirrored.

The mirror image is the same engine at the mirrored place: its geometry is mirrored, while all data of the engine definition, including the direction of rotation, remain unchanged. Engines that turn in opposite directions on the two sides are therefore defined as two engines and installed by two positions.

Example

A four-engine aircraft: an inner and an outer pylon hang on the wing, which is mirrored at the x-z plane, and one engine hangs under each pylon. Both positions reference the same engine definition and take the symmetry of the wing through their pylons, so that the excerpt describes four engines. Each fan plane lies 2 m ahead of and 1.5 m below the origin of its pylon.

<vehicles>
    <aircraft>
        <model uID="FourEngineAircraft">
            ...
            <wings>
                <wing uID="Wing" symmetry="x-z-plane">
                    ...
                </wing>
            </wings>
            <engines>
                <engine uID="InnerEngine">
                    <name>Inner engine</name>
                    <engineUID>Turbofan</engineUID>
                    <parentUID>InnerPylon</parentUID>
                    <transformation>
                        <translation>
                            <x>-2.0</x>
                            <y>0.0</y>
                            <z>-1.5</z>
                        </translation>
                    </transformation>
                </engine>
                <engine uID="OuterEngine">
                    <name>Outer engine</name>
                    <engineUID>Turbofan</engineUID>
                    <parentUID>OuterPylon</parentUID>
                    <transformation>
                        <translation>
                            <x>-2.0</x>
                            <y>0.0</y>
                            <z>-1.5</z>
                        </translation>
                    </transformation>
                </engine>
            </engines>
            <enginePylons>
                <enginePylon uID="InnerPylon">
                    <parentUID>Wing</parentUID>
                    <transformation>
                        <translation>
                            <x>4.0</x>
                            <y>10.0</y>
                            <z>0.7</z>
                        </translation>
                    </transformation>
                    ...
                </enginePylon>
                <enginePylon uID="OuterPylon">
                    <parentUID>Wing</parentUID>
                    <transformation>
                        <translation>
                            <x>8.2</x>
                            <y>17.3</y>
                            <z>1.5</z>
                        </translation>
                    </transformation>
                    ...
                </enginePylon>
            </enginePylons>
        </model>
    </aircraft>
    <engines>
        <engine uID="Turbofan">
            <name>Turbofan</name>
            ...
        </engine>
    </engines>
</vehicles>

Four engines of one definition, installed by two positions under mirrored pylons

Attributes

Name	Type	Constraints	Use	Description
`@externalDataDirectory`	`xsd:string`		optional	Directory of the external file the element was read from, as URI
`@externalDataNodePath`	`xsd:string`		optional	Path of the parent element in the merged dataset, at which the element was inserted from an external file
`@externalFileName`	`xsd:string`		optional	Name of the external file the element was read from
`@symmetry`	`symmetryXyXzYzType`	5 values	optional	Symmetry plane the component is mirrored at
`@uID`	`xsd:ID`		required	UID

Child elements

Name	Type	OccurrenceHow often the element may appear at this place. The schema writes it as minOccurs and maxOccurs on the declaration.	Description
allThe children below may appear in any order. Each may appear at most once.
`name`	`stringBaseType`	[1..1] required	Name
`description`	`stringBaseType`	[0..1] optional	Description
`engineUID`	`stringUIDBaseType`	[1..1] required	UID of the installed engine, defined in vehicles/engines
`parentUID`	`stringUIDBaseType`	[1..1] required	Component the engine is attached to, usually a pylon or the fuselage. The translation of the engine is then given relative to the position of this component.
`transformation`	`transformationType`	[1..1] required	Position and orientation of the engine coordinate system

enginePositionType

Attributes

Child elements

Used by

In a dataset · 2 paths

In the schema · 1 declaration