What is the proper way to measure wing area?

I can easily determine how many Sq. Inches or Sq. Feet in a wing half using Autocad. Is is but a punch of the button.

However, I have one old book which states to ignore the area which passes through a fuselage, and a different one which states the opposite.

In figuring wing area for loading calculations, should I use the total wing,

subtract out the area within the fuselage and engine nacelles on a multi,

should I use some formulae for it is is a high wing, a low wing, a parasol, or a mid-wing?

Should I use the area "as projected" due to dihedral, or as flat?

On large sized models adding in or subtracting out the areas is a significant number.


Wm.

This is just what I've picked up over the years but I always use total wing area including any hidden by fuselage and nacelles, measured flat (as built ). Effectively you have to do it that way for many modern aircraft because it's almost impossible to tell where the wing ends and fuse begins.

However large the plane it's not normally going to make a significant percentage difference.

A trickier question is whether to include the tail area or not (I don't).

Steve

When a wing intersects a fuselage or nacelle, the lift distribution does not suddenly go to zero. The lift distribution extends across the fuselage or nacelle with a dimished magnitude. How much the lift decreases depends on the width of the fuselage and the turbulence it generates. Also, fuselages can generate a little lift of their own if they are operating at a high enough angle of attack.

The reasoning behind some contest rules (FAI) requiring the tail to be included in the area loading calculations is to allow for tandem wing and canard configurations. In a normal, wing first, configuration where the tail is a small fraction of the wing area and the plane is trimmed for stability in pitch, the horizontal tail actually produces a downward force in level flight rather than contributing to lift. Accurate performance calculations require that the lift distribution of the entire aircraft be taken into account. Any departure from an elliptical lift distribution increases the induced drag. A wing that is interrupted by a fuselage, boom, nacelle, etc. will likely have a reduced effective aspect ratio.

Well, have been asked by a few foreign customers as to "exact" wing area on large free flight and some rubber powered models. With polyhedral wings, they want exact, vertical, wing area, the area consumed by the fuselage between the wing halves, and other considerations.

I do not know to what exacting rules they are going by, but to them a tenth of a square inch means something in consessions. Thus I am interested as to what should be considered as noted in question.

One of my friends mentioned last night, how do you consider wing area on something like an delta wing F-92.


Wm.

I saw your post and was wondering how I can determine the area of a typical wing tip from an already built model, without any plans to look at. This is what I think might work, tell me if it is close enough or am I missing something.
I streach a string around the wing tip from the tip wing rib at the leading edge around to the same rib at the trailing edge of the wing. lets call this distance 12 inches. then I measure the chord of the wing lets say 9 inches. On a piece of paper I draw a line 9 inches long to represent the wing chord. Then I attach my 12 inch string to the ends of the 9 inch line and streach it out so I form a right triangle. I can then measure the unknown side and compute the area of the triangle thus solving for the wing tip area.
Will this work?
Sparky

I use this simple procedure to measure the surface area of a wing panel, its fairly accurate.

Root wing chord LE to TE = RC

Wing tip chord LE to TE = TC

Wing panel length = PL

Example :

RC = 20"

TC = 8"

PL = 60"

RC + TC divided by a factor of two = 14, for two dimensions. You can use as many as you want if you prefer to measure the wing in various places. This will provide the average chord length.

28 divided by 2 = 14

14 multiplied by the wing panel length = the average surface area of the panel, or 840 square inches...

Multiply by two for two wing panels, 1680 squire inches actual surface area, then allow for the width of the fuse at the wing root area or 60 x 2 + 8 = total wing length or 128 x 14 =1792 total surface area.

The only practical thing you can do is ask your customers to tell you what rules they are working to. If they are operating in areas where a tiny difference (e.g. rounding a wingtip) is vital to them then they must know exactly what to measure. E.g. most FAI contest rules do not specify wing area but only what they call surface area which, as Olly says, includes the tail. The definition (from FAI Sporting Code Section 4C is :

"Surface Area (st)
The surface area includes the total surface of the wings and that of the horizontal or oblique stabilising surface or
surfaces. The surfaces taken for calculation are the orthogonal projection on to a horizontal plane of the surfaces in
question with each surface at zero incidence.

When wings or stabilising surfaces are built into the fuselage of the model aircraft the surface taken into account
shall include that area contained within the normal contours of the flight surfaces extended so as to meet at the plane
of symmetry of the model."

I read that as meaning "the projected area, taking into account dihedral, of both wing and tailplane including the bits in the fuselage". But I'm not an FAI judge .

However your customers may be working to local rules which differ. You'll never know without asking them.

Steve

"I streach a string around the wing tip from the tip wing rib at the leading edge around to the same rib at the trailing edge of the wing. lets call this distance 12 inches. then I measure the chord of the wing lets say 9 inches. On a piece of paper I draw a line 9 inches long to represent the wing chord. Then I attach my 12 inch string to the ends of the 9 inch line and streach it out so I form a right triangle. I can then measure the unknown side and compute the area of the triangle thus solving for the wing tip area.
Will this work? "

Elmshoot,
Unfortunately that idea doesn't work.
In my cad system, I started with your chord of 9 inches and connected the 12 inche long curve/arc to either end. Assuming an arc of a constant radius (cause that all the info I have to work from) the wingtip area is 22.12 sq inches.
Now if you take that arc and stretch it out to a right triangle, the area is reduced to 11.81 sq inches.

Cheers.
James