Longaly

This is my first attempt at designing and scratch building. I am quite ignorant in structural design and have a problem with wing twist\flex. The ribs are 1/16 balsa except for the two towards the center which are 1/4 balsa. The spar is 1/4 x 1/4 spruce and 1/16 balsa shear web. I am trying to stay away from sheeting the leading edge and center section to save weight.

My problem is that this wing twists very easily with very little effort and I don't know where and what kind of bracing to add in order to stiffen this thing up. I was thinking two additional angled ribs running from the rear of the spar to the trailing edge between the existing ribs but wanted to get some help and info from the experts here. I already have it framed up as shown so if there is any way to add to, rather than start over, that would be nice!

Thanks for any and all suggestions.

SPECS:

WS 35"

CORD minus ailerons 8.5"

[img][/img]

Tall Paul

Adding a vertical shear web at the trailing edge will make your wing stiffer.
It will stiffen up when it's covered.
This wing is similar and covered with tissue/dope.. It doesn't twist.

Longaly

Tall Paul,

I was wondering about that myself but wasn't sure because there is really a lot of flexibility. That may be the answer though. Thanks for the reply.

Rick

Tall Paul

The forum software sucks.
It won't do an image edit anymore...
Here's the image...

Longaly

Posted before your edit showed up. I may try the trailing edge shear web. Thanks again.

Rick

Tall Paul

I've been amazed how adding the vertical web to a built-up trailing edge stiffens a wing.
With a D-tubed leading edge also, the wing will NEVER twist! Or untwist, if you built in a warp!
I use it all the time now when I use a built-up trailing edge.

Longaly

Tall Paul,

Thanks for the help. I added shear web at the trailing edge and it stiffened the wing right up. Thanks again.

Rick