# Aerospace How to solve for bending moment?

1. Mar 4, 2010

### airstrike_ola

Hello, I'm a newbie here, please help me to solve for the bending moment of my design airplane. I want to know if my wing spar is strong enough to support the weight of my design which is 490 lb. I want also to know if what is the breaking point of the wing spar. Please see the attached picture.

Thank you...

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2. Mar 4, 2010

### minger

You can assuming that your beam is simply supported at the wing tips, with a point load at the center, and then just either simply compute the bending moments in your beam. The stress is then just
$$\sigma = \frac{My}{I}$$

Or I'm sure a decent google result will give you the closed form solution given your geometry.