Saturday, December 29, 2007

Wing inertia

For handling quality studies, mass distribution & inertia the saiplane are part of the eigen modes solutions.
It is nevertheless very difficult to access such data among existing sailplanes.

Here is a simple spreadsheet tool that evaluate inertia of a wing on main axes (Ixx, Izz, Iyy) .

Some simplifying hypothesis are made (wing seen as a beam, simplified mass distribution, etc), in order to be able to evaluate realistic values of inertia.

Inputs :
  • estimation of the spar & "skin" mass
  • geometry elements
  • water quantity
Simplifying hypothesis are made about how to spread/share thoses mass along span & chord. The effects of filling tanks is also evaluated, once again with some hypothesis.

Outputs :
  • Inertia/ inertia radius, at elements CG
  • Inertia/ inertia radius, at wing CG
  • Inertia/ inertia radius, at a reference point
Similar modeling will be needed for fuselage.

If you happen to have data on sailplane inertia, just tell me !

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