How correctly use Simple Variable Mass 3DOF (Body Axes) block?

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Leonardo Molino 2024-9-11，11:35

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评论： Leonardo Molino 2024-9-11，13:47

Hello,

As in the title, I need to simulate an aircraft mission with varying mass. In the Aerospace Blockset, I've so found the Simple Variable Mass (3DOF). I have some problems in interpreting these inertia definitions:

Empty inertia — Body inertia when fuel tank is full
0.5 (default) | scalar
Body inertia when the fuel tank is full, specified as a double scalar.

and

Full inertia — Full inertia
3.0 (default) | scalar
Full inertia of the body, specified as a scalar.

My concerns involves the difference between Empty and full inertia. From the documentation, they seem to be the same. Can anyone help me?

Thanks.

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Answer 1

Vandit 2024-9-11，13:33

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Hello Leonardo,

As per the documentation, let me clarify these definitions for you:

The term "Empty Inertia" refers to the body inertia of the aircraft when the fuel tank is full. On the other hand, "Full Inertia" refers to the body inertia when the fuel tank is empty.

The key difference between these two lies in how the mass is distributed within the aircraft. When the fuel tank is full, the center of mass is typically closer to the center of the aircraft, which results in a different moment of inertia compared to when the tank is empty. As fuel is consumed, the distribution of mass changes, affecting the aircraft's dynamics.

I hope this helps.