Anyone have a heat map of wing stress points as G loading increases?

SixPapaCharlie

SixPapaCharlie

May the force be with you
Joined
Aug 8, 2013
Messages
16,020
Display Name
Display name:
Sixer
Mentally I imagine the body being supported by the tips which I know isn't the case.
I'd like to see where along the wing the stress points are as Gs are increased.

Obviously the whole wing is lifting.

Anyone have anything like that?
 
From: https://www.raetech.com/Analysis/Analysis.php

view%20of%20using%20rigid%20bolt.PNG
 
You really need to look inside the wing at the spar and cross members to get an idea of where the stressed areas are. The wing skins themselves aren't stressed that much.
 
Sac Arrow said:
You really need to look inside the wing at the spar and cross members to get an idea of where the stressed areas are. The wing skins themselves aren't stressed that much.
Click to expand...

I just kinda mean in general. I watched the FLY8MA vdeo where he is destroying that Cherokee.
He was showing missing rivets on the aft spar and it got me thinking.

If a plane is pulling 2G and I am looking at the plane head on, in my mind the majority of the pressure would be at the attach point but I think that might not be right since the entire wing is flying.
Perhaps the pressure is distributed differently than I am thinking.
 
The aerodynamic pressure distribution is indeed not linear nor uniform. It's a cantilever wing, the static analysis is pretty straightforward.
upload_2020-5-30_15-5-31.png

Load distribution
upload_2020-5-30_15-6-30.png

And deflection:
upload_2020-5-30_15-7-2.png


ETA: Fly8MA is kinda of a douche for doing the airplane trashing thing. "aNaLyTiCs" and monetization notwithstanding.
 
SixPapaCharlie said:
I just kinda mean in general. I watched the FLY8MA vdeo where he is destroying that Cherokee.
He was showing missing rivets on the aft spar and it got me thinking.

If a plane is pulling 2G and I am looking at the plane head on, in my mind the majority of the pressure would be at the attach point but I think that might not be right since the entire wing is flying.
Perhaps the pressure is distributed differently than I am thinking.
Click to expand...
The images and such posted above provide some information. It gets a little more complicated when you go from a cantilevered wing to one with struts, and also when you add things such as tip tanks which act opposite the lifting loads.
 
Think you need to differentiate pressure and stress. The pressure is distributed across the wing, the stress is concentrated at the spar attach point. There is stress across the structure of the wing as well, but the sum of all that pressure is stressing the spar. At least in an aluminum low wing, more complicated in a high wing with struts.
 
This is with a strut (Skip to 4:20...)

Without the strut, the loads are highest right at the wing root, but that's where there is the most structure (typically).
 
The real problem is when you get stress concentrators from corrosion, damage or bad repairs.
 
Hang 4 said:
Think you need to differentiate pressure and stress. The pressure is distributed across the wing, the stress is concentrated at the spar attach point. There is stress across the structure of the wing as well, but the sum of all that pressure is stressing the spar. At least in an aluminum low wing, more complicated in a high wing with struts.
Click to expand...

Not quite. Yes, you need to differentiate pressure from stress, and from force. The force is concentrated at the attach point. Pressure and stress are both expressed in force per unit area (e.g. PSI, pounds per square inch). Aerodynamic pressure on the wing skins creates a force against the wing ribs and their attaching rivets. This creates stresses in the rib material, but the force transferred to the spar, which then has its own internal stresses. You end up with rather high forces against the wing attach hardware, which creates stress in the wing attach fittings and bolts.

So the forces will be highest at the wing root fittings (for a cantilever wing), but the stress will be highest wherever the force divided by area is greatest, which may or may not be the same place as where the force is highest.
 
3393RP said:
You call that straightforward? I almost got vertigo slogging through it!
Click to expand...

Lol indeed. Now you know why I gave that drudgery up. 50pct of my username's origin story is tied to that tidbit.
 
You must log in or register to reply here.
Back
Top