Wing Spar Shear And Moment

Let's calculate the shear stress and bending moment of an airplane's wing spar. Once we have this information we can then start on the wing spar design (in a later video).
Link to the Ultralight Airplane Workshop's books web page, including "Simplified Aircraft Design for Homebuilders""
www.ultralight...
Links:
CZcams Channel: / @designer103
Patreon: / ultralight_airplane_wo...
Facebook: / ultralightairplanework...
Twitter: / designer1032
Website: www.Ultralight...
FAA AC 103-7: www.faa.gov/do...
Xflr5 software:
OpenVSP: openvsp.org/
Music: www.bensound.com
Disclaimer: If you use any of the information that you see on this video on a project of your own, YOU become the engineer and responsible party for your project. It is possible that miscalculations were made in the production of this video. Since you are now the engineer for your project, you must verify the information that you use.

[@niio111]

Great info. Moving the reference point for aggregate moment along the wing seems harder than just adding each lift x arm for each station outboard of the calculation point.

[@abdbot2509]

Congratulation, the quality of the exposed material is satisfying

[@alexorrbit3335]

Very thorough explanation, thank you!

[@SomeTechGuy666]

Very well explained. Good job.

[@Prashantkumar-tp3sp]

can you elaborate the formula used for Schrenk Span Dist.

[@rhemaislife]

Thanks a lot man

[@Dasni12]

If I'm not mistaken for the bending moment could you use the method used to find the shear force, but replace the lift force with the shear force instead?

[@jakbain1337]

It's been a while so happy to be corrected but at 7min50sec shear from torsion is in the same radial direction through the cross section unless the tube isn't closed (has a slit down the length) then the shear stress is as shown in the diagram?

[@dehagunay3390]

Can you make a new video that includes engine etc. loads on span?

[@anthonyrstrawbridge]

👍

[@ryancurran2839]

Hi could you tell me what formula you used for the schrenk span dist please

[@Designer103]

There isn't exactly a formula. You add an elliptical distribution (you can find these online) to a distribution that has the same shape as the planform of your wing. If you get Chris Heintz book "Flying on Your Own Wings" you will find the description on page 133.

[@TheJustinJ]

Use a free 2D CAD software, draw an elliptical shape that has the same area as the lift. (Gross weight, times G load, multiplied by distance Center of Gravity is located in front of Aerodynamic Center, plus tail down-load).
Draw the ellipse to represent the total load and lift with its area, make it the same span as the wing.
Now, draw the wing planform sharing the same span and centerline.
Now, scale the wing planform in 1D (vertically) until its area also equals the lift, same area as the ellipse.
Now, draw small lines between the ellipse and scaled wing planform. It should be a relatively short distance.
Now, place a point at the mid-point on each line. And connect them with a curve. The curve line should interpolate between the ellipse and the wing planform.
This can be done on higher end CAD programs such as Rhino3D with the command "Tween two curves".

[@iforce2d]

I think my comment got marked as spam again :)

[@isaoyamasita5368]

Terribly low volume audio.