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 !

Mesured sink polar of LS6

Here is the scan of original LS6 sink polar, as measured by DLR back in 1986 :

The reading of this polar has confirmed to me the way to fly (without water):

Do not use flap -5 before 150kph !

Then, up to 150 kph you are virtually flying a LS8...

Preparation of technical study of LS6 glider

I am collecting as much technical information as possible about my glider type.
if you have any information, please don't hesitate to contact me
matthieu.scherrer'at'free.fr

The objective is for me to test available tools for aerodynamic computaton and prediction on a precise book case. I base my study on on LS6 measured planform and wing airfoils.

The geometry of LS6 wing have been translated for MIAReX, my tool coupling lifting line theory and Xfoil results.
The final objective is to test how accurate such a tool could be at predicting the speed polar, and have a first hestimate of non linear behavior of the wing for handling quality evaluation.

I have also been preparing the formated file for having the complete saiplane geometry of LS6 available in AVL.
The objective is to be able to study the rigid, linear handling quality of the LS6 glider over its flight domain.


Using those tools, I hope to progress in the understanding and prediction of the aerodynamic of sailplanes, and mine in the first place !