Please show me how to find the CG

[Mike Hall]

I need to learn how to locate the CG on different types wings, and this is the wing im working on now so if you know how to find the CG on it please talk me through it.

Thanks
Mike

[Sparky Paul]

For this T-6/DC-3 style wing...
Extend the leading edge at the break to the centerline.
Use that for the root chord..
Then find the 50% chord line.
Place a root chord line at the tip, a tip chord
line at the root as shown.
Connect the ends.
Where that line crosses the 50% line is the m.a.c.
Figure the c.g. for that chord, and project to the root.

[Mike Hall]

Boy that was fast. Should i move the spar to the CG or leave it were it is? I would like to havethe spar on the CG but that might move it back to far.

Thanks
Mike

[Mike Hall]

OK the M.A.C. is 6.358" Now how do i fugure the GC for the M.A.C.?

Thanks
Mike

[Mike Hall]

I found a CG calculator on a web site and its saying tha the CG will be @ 79% of the root cord. IS this right. that would put the CG right at the ailerons.

Mike

[Sparky Paul]

This location works well...
The "mac distance from root" refers to its position out the span.

[Mike Hall]

Thanks thats more like it.

Mike

[Robbie d]

i answered a similar query that with a method that doesn't require you to know any angles, percentages or anything like that.
you can calculate the cg of any wing easily using nothing but a ruler and a pencil. First measure your root and tip chords.
The red lines on the diagram represent the root chord and the light blue lines are the tip chords. You draw the chord lines top and bottom. Then draw two intersecting lines (the dark blue ones) from the tip of each line and where they cross is the c of g.