Moment of Inertia

[flash369]

I would like calculate the moment of inertia of a boeing 737 about the 0x(Ix), 0y(Iy) and 0z(Iz) and 0zx(Izx) axes. I have searched extensively to no avail.

I would appreciate any information on how ot calculate them. Thanks

 

[Wittenborn]

katanator,

Unfortunately, that is not a straight forward calculation. To get an accurate estimate of the moments of inertia, you will need the weight distribution of the airplane. The moments of inertia will vary for different loading and fuel conditions as well.

If you are looking for a "rough" estimate, as inertias relate to weight, there is a correlation in Roskam's Design Textbooks, Part V I believe it is. The book presents a correlation, a trendline if you will, of airplane weight to inertias about all axes, as well as products.


Regards,
Grant
Aerospace Engineer

 

[hombre]

Some clarification is needed... are you wanting the area moments of inertia for stiffness calculations or the mass moments of inertia for structural dynamics calcs?

Area moments may be calculated as outlined in Bruhn's Analysis and Design of Flight Vehicle Structures. Essentially, the area and location of the stringers are used. The skin is also taken into consideration but is dependent upon whether it is in tension or compression.

Hope this helps as well,

Hombre

 

[Wittenborn]

Great point, Hombre.


Regards,
Grant
Aerospace Engineer