Difference between revisions of "Center of lift"

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[[File:Col icon.png|framed|left|Icon]]
 
[[File:Col icon.png|framed|left|Icon]]
 
[[File:Com col cot.png|thumb|The center of lift within the center of mass indicator]]
 
[[File:Com col cot.png|thumb|The center of lift within the center of mass indicator]]
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The '''Center of Lift''' is one of three measurable "centers" used mainly in [[Spaceplane|spaceplanes]], showing axis and direction of lift, provided by wings, control surfaces and [[Winglet|winglets]]. inside the editor is showed as a cyan ball (axis) along with an arrow (direction of the lift)
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The '''center of lift''' (abbreviated '''COL''' or '''CoL''') is the point where the sum total of all [[lift]] generated by parts — principally by [[wing]]s, [[control surface]]s, and aerodynamic fuselage parts — balances out and the aggregate direction their force will act on a [[craft]] while in an [[atmosphere]].
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Along with the [[center of mass]] (COM) and [[center of thrust]] (COT), it is one of three key physics properties determining a craft's behavior while in motion. Display of the COL can be toggled in the [[editor]] where it is seen as a cyan and black checkered sphere with a cyan arrow extending out of it.
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== Usage ==
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Like [[w:Thrust|thrust]], lift is a force acting on a craft with its fulcrum at the center of mass. The COL has a vector arrow pointing the direction that lift will push through the COL, and thus which way it will tend to pitch (up or down), yaw (left or right), or even roll (clockwise or counterclockwise). This force becomes stronger the faster the craft goes and thicker the atmosphere is around it.
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It can alternatively be understood as the ''center of [[drag]]'' that forward momentum will try to place behind the COM like the feathers fall behind the head of an arrow in flight.
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=== Flight characteristics ===
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Different flight characteristics are desired in different craft. If the COL or the lift vector is positioned or pointing off-center left-to-right, the craft will turn. If the COL is positioned too far toward the bottom of the craft, it will want to roll over. Assuming the COL is centered side-to-side, and possibly top-to-bottom, performance is basically as follows:
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* COL ahead of COM → Flips or turns uncontrollably
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* COL inside COM → Excessively maneuverable; needs constant course correction
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* COL closely behind of COM → More maneuverable
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* COL further behind of COM → More stable
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* COL very far behind of COM → Very hard to correct course; likely to flip up or nosedive
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=== Shifting fulcrum ===
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The center of mass will shift as fuel is consumed or stages detach. This may critically alter the relation between the COM and COL to alter the flight characteristics. It is not possible to see the COM, or the other centers, outside the editor. However, using [[tweakable]]s in the editor to alter the fuel level or temporarily taking stages off, or both, will alter the position of the COM, and COL if staged parts generate lift. This can reveal issues that would cause nonstandard flight profiles before actually launching.
  
== Uses in Spaceplane building ==
 
The center of lift in a spaceplane defines is behavior one in flight. Depending on where is located, the shifting weight of fuel and location in relation to the [[center of mass]] can turn a plane very unstable. It's recommended to place the center of lift slightly behind the center of mass, to prevent it from being behind the center of lift, otherwise making it unstable and hard to maneuver.
 
 
== See also ==
 
== See also ==
 
* [[Center of mass]]
 
* [[Center of mass]]
 
* [[Center of thrust]]
 
* [[Center of thrust]]
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[[Category:Physics]]
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[[Category:Game interface]]

Latest revision as of 18:46, 17 March 2017

Icon
The center of lift within the center of mass indicator

The center of lift (abbreviated COL or CoL) is the point where the sum total of all lift generated by parts — principally by wings, control surfaces, and aerodynamic fuselage parts — balances out and the aggregate direction their force will act on a craft while in an atmosphere.

Along with the center of mass (COM) and center of thrust (COT), it is one of three key physics properties determining a craft's behavior while in motion. Display of the COL can be toggled in the editor where it is seen as a cyan and black checkered sphere with a cyan arrow extending out of it.

Usage

Like thrust, lift is a force acting on a craft with its fulcrum at the center of mass. The COL has a vector arrow pointing the direction that lift will push through the COL, and thus which way it will tend to pitch (up or down), yaw (left or right), or even roll (clockwise or counterclockwise). This force becomes stronger the faster the craft goes and thicker the atmosphere is around it.

It can alternatively be understood as the center of drag that forward momentum will try to place behind the COM like the feathers fall behind the head of an arrow in flight.

Flight characteristics

Different flight characteristics are desired in different craft. If the COL or the lift vector is positioned or pointing off-center left-to-right, the craft will turn. If the COL is positioned too far toward the bottom of the craft, it will want to roll over. Assuming the COL is centered side-to-side, and possibly top-to-bottom, performance is basically as follows:

  • COL ahead of COM → Flips or turns uncontrollably
  • COL inside COM → Excessively maneuverable; needs constant course correction
  • COL closely behind of COM → More maneuverable
  • COL further behind of COM → More stable
  • COL very far behind of COM → Very hard to correct course; likely to flip up or nosedive

Shifting fulcrum

The center of mass will shift as fuel is consumed or stages detach. This may critically alter the relation between the COM and COL to alter the flight characteristics. It is not possible to see the COM, or the other centers, outside the editor. However, using tweakables in the editor to alter the fuel level or temporarily taking stages off, or both, will alter the position of the COM, and COL if staged parts generate lift. This can reveal issues that would cause nonstandard flight profiles before actually launching.

See also