Difference between revisions of "Center of thrust"

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[[File:Cot icon.png|framed|left|Icon]]
 
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[[File:Com and cot.png|thumb|The thrust points away from the center of mass]]
 
[[File:Com and cot.png|thumb|The thrust points away from the center of mass]]
 
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The '''center of thrust''' or '''thrustvector''' is the direction in which the thrust is acting and on which point the thrust acts on the [[craft]]. The thrustvector and [[center of mass]] should be in one line to minimize steering.
 
  
Placing engines above the center of mass doesn't make a craft more stable, which is usually called pendulum rocket fallacy. In Kerbal Space Program such craft might be more unstable, as [[thrust vectoring]] needs to be applied inverted, when the engine is acting above the center of mass. So one way is to deactivate thrust vectoring, which makes rocket hard to steer especially in atmosphere. Another way would be to control in the other direction. To prevent the systems to counteract, torque of [[reaction wheel]]s needs to be deactivated and all [[control surface]]s needs to be removed.
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The center of thrust (or CoT)is one of the three "centers" you can measure in the [[VAB]] and [[Spaceplane Hangar]] along with the [[Center of Lift]] and [[Center of Mass]] abbreviated CoL and CoM respectively. The CoT is the direction in which the thrust is acting and on which point the thrust is acting on. The CoT and center of mass should be in one line to minimize steering losses. It is important to note that the CoT is calculated based on ALL rockets on the [[craft]]
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Not just the rockets in any individual stage. As you activate/deactivate engines, detach engines, run out of fuel, and even dock with other craft, the CoM and CoT will change.
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== Reading the Center of Thrust ==
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The Center of Thrust  is used mainly to determine a rockets' behavior in flight by comparing its position to the Center of Mass. It's basically the same as the Center of Lift but this is generated by rockets rather than wings. If the CoT is left of the CoM then the rocket tilts right, to far right, and it tilts left. It behaves similarly if it is to far forward or backwards. The CoT should also be above the CoM as well, if it is below the CoM then the rocket will be top-heavy and be prone to tilting.
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This is usually called pendulum rocket fallacy. In Kerbal Space Program such craft will be less efficient, as [[thrust vectoring]] needs to be applied to keep the craft pointing straight,and the thrust spent doing that is no longer available to push the rocket up like it normally would be. You can fix steering problems by adding rockets with [[thrust vectoring]], adding an [[RCS]], or adding [[control surface]]s.
  
 
== See also ==
 
== See also ==

Revision as of 14:47, 30 October 2014

Icon
The thrust points away from the center of mass
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The center of thrust (or CoT)is one of the three "centers" you can measure in the VAB and Spaceplane Hangar along with the Center of Lift and Center of Mass abbreviated CoL and CoM respectively. The CoT is the direction in which the thrust is acting and on which point the thrust is acting on. The CoT and center of mass should be in one line to minimize steering losses. It is important to note that the CoT is calculated based on ALL rockets on the craft Not just the rockets in any individual stage. As you activate/deactivate engines, detach engines, run out of fuel, and even dock with other craft, the CoM and CoT will change.

Reading the Center of Thrust

The Center of Thrust is used mainly to determine a rockets' behavior in flight by comparing its position to the Center of Mass. It's basically the same as the Center of Lift but this is generated by rockets rather than wings. If the CoT is left of the CoM then the rocket tilts right, to far right, and it tilts left. It behaves similarly if it is to far forward or backwards. The CoT should also be above the CoM as well, if it is below the CoM then the rocket will be top-heavy and be prone to tilting.

This is usually called pendulum rocket fallacy. In Kerbal Space Program such craft will be less efficient, as thrust vectoring needs to be applied to keep the craft pointing straight,and the thrust spent doing that is no longer available to push the rocket up like it normally would be. You can fix steering problems by adding rockets with thrust vectoring, adding an RCS, or adding control surfaces.

See also