Stuka Stunt Main Forum · 51 of 51 known posts recovered
I do it this way. Tip cord including flaps plus the root chord plus the flaps divided by 2 gives average chord. Multiplied by the span gives wing area. That included the part within the fuselage. If you deduct that area (inside the fuselage) then you have what I call effective wing area minus the tip area. As far as tip area goes, I just trace it on graph paper and figure it out by the 1/4" squares - of course some wings don't really have tips, like the twister, Infinity, and others, that makes them a little easier to figure the wing area of.
Hope this helps some.
Jim Pollock 
so I just didn,t feel c0nfident. Sometimes the advertised specs are wishful thinking!
I don't think that a lot of advertised wing area's are completley accurate!
Jim Pollock
I agree. Most of the stated areas are greater than what I compute from measuring the plans. A couple times it's been the other way.
SK
SK
Al
What's different? Presuming that you didn't include the flaps twice, it sounds right on to me.
SK
Nope your not different, I used to do it that way myself. It just seems a little easier with the flaps added since some flaps are not full span and then you have to figure out what the part between the tip and the flap is too. Of course you could just add that to the flap area too.
P.S. I really loved your story about the Mustang - Kinda reminds me of my early Flight Instructor days!
Jim Pollock
The area of a wing is totally independent of the airfoil or how fat or how thin the airfoil is. Area is based on projected measurements of chord and span.
And as has been mentioned in this thread, the convention in full scale aeronautics is that area enclosed by the fuselage (and nacalles) is included in the total wing area. This has served full scale airplane designers for some time until unusual configurations are chosen and/or high performance aircraft are being designed.
Similarly, the convention to include the area within the fuselage has been the accepted norm in CL Stunt design over the years. It makes a convenient and consistent reference when comparing designs and when starting a new design. This includes the total projected area of the wing, including the portions of the wing that are used as flaps. Then, there could be a question of how to express total flap area. When comparing designs or starting on a new design, it is useful to calculate effective flap area as a percentage of total wing area which is inconsistent in a way as effective flap area does not include that portion of the flap area that would be inside the fuselage. It is still a useful to measure the flaps in this way, particularly in the case where the flaps are not full span.
wheigh it.
trace the wings.
cut
weigh
the percentage of what the cut cardboard has in relation to the original is the area.
example: a 1000 sq" cardboard, wheighing 10 oz after cut wheighs 7 oz.
wing area is 700 sq "
Ion
I always extend the flaps into the fuselage when I do this. Never figured this was a problem as there is a lift generated by the fuselage that probably excedes the lift from the small area inside the fuse.
If you have access to a CAD program like AutoCAD, getting the area is trivial, you simply use an AREA command and identify the perimeter edges. However, when I did this on the Roadrunner, I got a lot of static for several folks (including one of the designers, Bill Melton), who insisted that that area was well over 600 square inches (it was really ~590 or such..). (To be fair, Bill built several Roadrunner derivatives with stretched wing spans..)
No use arguing with someone who can eyeball the wing and proclaim its area, which overrides the AutoCAD measurement!
Perhaps a more meaningful value for assessing lift capability would be the entire VOLUME of the wing, but this would really cause some headaches, even though CAD programs can do that also..
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"Everything goes on forever since the fat lady retired."
Your method reminded me of my father, who was a carpenter. I was telling him how you could calculate the area of an irregular quadrangle using calculus. He suggested simply cutting one and weighing it versus the weight of a piece of the same material of known area.
While CAD programs and mathematical methods may be clever, your method is quite PRACTICAL..
(Como esta usted, amigo?)
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"If life was a box of chocolates, it'd be pretty empty."
Lay out the plans or the wing itself and find a ball of string. Now lay out the string carefully following the outlines of the wing itself. Snip off the string when you get back to the starting point.
Now, carefully arrange the string in a square shape insuring all four sides are equal. Measure a side and then multiply that number by itself to get the area of the square.
Pretty neat idea, huh.
Anybody see a problem with that?
Ted
p.s. this is a quiz!
UHHHHH ....... Ya! But he does make it "square inches" 
Hey, at least that would work for elliptical wings. without a CAD drawing, figuring elliptical wing area is a pain.
Randy Powell
I have a modeling booklet printed by Flying Models Magazine in 1962 which gives the following formulas for computing wing areas:
Ellipse Area is Length X Width X .7854
Parabola Area is Length X Width X .666
The accompanying illustration shows the complete wing for each.
Being a retired "bean counter" I guarantee nothing. Maybe these are at least "ball park" figures.
Mel
Did you count eliptical beans or parabolic beans? 
I never could figure out which type I was working on. Jim Pollock's original post gives the method I have always used (mean chord x span). Then I just fudge the tips. Not good enough for the free flight contests, but fine for CLPA.
One thing to remember about an ellipse is that it is sort of a squashed circle.
If a wing has the planform of a circle, its area is:
Span times Chord divided by pi/4 or S*C*pi/4 where pi/4 = 0.7854
which is the same thing as pi times the radius squared (the area of a circle)
If an eliptical wing planform is a true elipse, its area is calculated similar to the circle wing planform described above:
Span times Chord divided by pi/4 which is the same as Mel found in the FM data sheet.
But make a square out of that 8 feet of string. Now, it is 2 feet on each side. You would get 4 square feet.
Currell
Ta dah! Currel broke the code. Even worse, make the top and bottom four feet each and the sides zero and the area is zero.
Sounded clever, huh. Then Uncle Jimby scratched his head and said something like "...you've got to be kidding!" Jimby was right, the unknown originator said "...oops"!
Sounded good at first though, didn't it?
Ted
You have 24 hours to leave the town... 
God bless you!
In Jesus,
Ion
The wing area in the fuse is usually incidental, and makes little difference in any calculation you might use the wing area for. If you look on some other aero sites there are some good pictures showing what happens to the airflow over the wing and fuse. The fuselage generally does nothing but upset the airflow and reduce lift.
Geometry, we don't need no stinkin' geometry, use Calculus!
Jim Pollock 
x + y = C (where C=1/2 of the perimeter)
xy = Area
so you end up with
Area = (
C-x))
= -(x^2)+xC
The above is a quadratic equation that bulges upwards, so the maximum area is where the slope of the line is zero (where Area' = 0).
Area' = -2x + C = 0
2x = C
x = C/2
So the maximum area is when x = C/2, or 1/4 of the perimeter. Since
x+y = C,
y is also C/2, and therefore the maximum area is when you have a square.
C-x)) Make that
Area = (x (C-x ))
Hi Ted,
I have a big problem with that. It does not work.
You can arrange the string loop around a rectangular shape where the length of the rectangle is quite long and the width is infinitesimally small (as in a wing approaching an infinite aspect ratio) where the rectangle approaches zero area. Yet, that string loop in the shape of a square will have an area many times that of the rectangle. (And as has been correctly explained by Currel, the maximum area circumscribed by that loop of string would be a circle.)
Using the perimeter will not. A 99" x 1" rectangle and a 50" x 50" square have the same perimeter (200"). However the area of the 99" x 1" rectangle is 99 sqr. inches, and the 50" x 50" square is 2500 sqr. inches.
The method sugested by Ted will always be optomistic.
Glen
estou bem, mas no Brasil falamos português, não espanhol...
"Ustedes" in portugues is "Você" 
bless ya!
Ion
No matter, tambien, no se hablo Espanol!
Hey, what happened to your Stuntrib programming? (Speaking
of languages, I'm pretty ignorant of C as well. By now, you've
figured that out from looking at my code..)
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"Few things are harder to put up with than the annoyance of a good example." -Mark Twain
You beat me to it! This is the way we used to do it at Free Flight meets where wing area is regulated, I've done is lately as well because of some of the odd tip shapes you see. Semi-elipticals are an real pain, even some of the Free Flighter were surprised by this one. Where did you hear about it?
Randy Ryan
AMA 8500
SAM 36
I fly 'em all and love it!
I learned this wing area measuring trick on some article about "tricks and ideas", but I can't remember where and when...
Ion
A = area in square inches
L = Length in inches
W = Width in inches
Suppose you have a straight wing that is 10" from LE to TE and 40" from wing tip to with tip. The formual will be A=10x40 so the Area is 400 square inches.
Suppose you have a tapered wing with 8" wing tips and 12" at the fuselage. To find the average wing width you add 8 + 12 then divide by 2 and you get 10". If the wing span is 42" the formula will be A=10x42 so the Area is 420 square inches.
I never count the fuselage as part of the wing area.
Of course (going back to my 8 feet of string example in Message 22), the max area you can make out of it is a circle.
circumference = 2 X Pi X r (radius)
8 = 2 Pi r
r = 4 / Pi
r = about 1.27
Area = Pi X r X r
Area = 3.14 X 1.27 X 1.27
Area = 5.06 square feet
This beats the 3 and 4 square feet that I have in my two examples earlier, using the same 8 feet of perimeter string.
I do like Ion's idea. I have used it once or twice.
I recall the stated Nobler squares are off some.
Currell
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"It is the childlike mind that finds the kingdom." -Charles Fillmore
>Perhaps a more meaningful value for assessing lift
>capability would be the entire VOLUME of the wing, but this
>would really cause some headaches, even though CAD programs
>can do that also..
I dunno.. you'd have to convince me that a 18% wing can lift twice as much as a 9% wing of the same area, which I really doubt is the case.
However, it would be fun to bring up Francis Reynold's concept of Wing Cube Loading here. He noted, in his column, that with the same basic airplane (say, a Piper Cub) that flies in a particular way (relatively slow cruise, nothing extreme aerobatic-wise, say), traditional wing loading gets higher and higher the bigger the airplane. A full scale Piper Cub has a much higher wing loading than, say, a 1/12 scale model would. But when you calculate Wing Cube Loading of the two, they're very close to being the same.
What is Wing Cube Loading? I'd have to pull out my old Model Builder magazines, but if I recall correctly, it's
(wing area^(3/2))/weight).
(Since most stunters are within a third of an order of magnitude of each other in size, wing loading's plenty good enough for comparison for our purposes..)
>(wing area^(3/2))/weight).
Hey, pretty good memory. Actually he used the reciprocal:
W/(S^1.5) (oz/ft^3)
on his graph. As you noted, although it showed full scale aircraft centered at a bit over twice the displacement loading (lb/in^3) of R/C pattern models, they were centered at only about 20% more wing cube loading and overlapped the models in WCL (Model Builder, 9/89). Larry Renger ('Design Man') has compiled an interesting spreadsheet relating to other scaling factors of similar use for a variety of his models.
SK
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"Intellectuals solve problems; geniuses prevent them." -Albert Einstein
What is Wing Cube Loading? I'd have to pull out my old Model Builder magazines, but if I recall correctly, it's
(wing area^(3/2))/weight).
(Since most stunters are within a third of an order of magnitude of each other in size, wing loading's plenty good enough for comparison for our purposes..)
Isky,
I'm not sure why, but I am a little surprised you know of Francis and his theory on loading.
Francis has done some pretty neat things over the years, he used to be one of the few people I would seek out at our local RC field. He was generally involved in some very weird stuff, none of which I had any interest in replicating, but one could always learn something from him.
From whom do you think H. Rush got the idea to taper foam-cutting wire?
Several years ago I ran into Francis at our local Big Time hobby show and asked him what he judged to be the model putting into play the most advanced technology. His reponse is not important, as I was not impressed with his choice, immediately introducing him to long-time friend Ralph Cooney (Fourmost Products) who at that time was heavily involved in F1C and building his own stuff versus kits and ARFs from ex-Soviet bloc countries. Ralph was asked to give Francis a quick tour through an F1C Ralph had on display.
Next time I saw Francis, couple hours later, he was still dazzled by the wonder of it all, had changed his mind as to the full application of new technology being the province of some semi-clunky RC model...
Ya never got back to me on the C5 thing.
Dan
The aspect ratio btw, is the span (B) squared divided by the reference area.
The curved area of the wing is called the "wetted area".
Since I know Igor is watching this, I may still have some DOS based programs laying around that can be used to evaluate aircraft performance. They even have a CAD module that allows you to draw the airplane and input the airfoil coordinates. You can evaluate parasite drag and all kinds of cool stuff. I'll see if I can dig them up and make them available if I can get the old 486 box running this weekend. I also have some propeller/engine analysis tools now that I think of it. If I can resurrect them I'm sure you guys will have a ball with them.
Igor is not watching, Igor is sometimes some weeks out, but Igor comes back after
>>>I also have some propeller/engine analysis tools now that I think of it. If I can resurrect them I'm sure you guys will have a ball with them.<<<
Sounds important. I was thinking about a sheet where I can enter diameter, pitch and pitch distribution. If it can tell actual thrust at known speed and also power absorption, then comparing those numbers to the power curve slope at operation rpm will tell speed stability of that combo. I am not so far, I did it for “some” airfoil with constant drag coefficient at operation rpm (like semi symmetrical airfoil), I have sheet telling thrust with relatively good approximation and also telling torque (thus also power) necessary to maintain airfoil drag with vortex at tip (means no other “air mixing”). I do not have any background of props, but I think it is the only changing with longitudinal speed difference.
So I do not know how close I am, but in any case it clearly shows when and how the pitch distribution brings some advantage. It nicely shows effect of Beringers lowered tip pitch and when it works and also when it does not help (and when is more pitch at tip better).
It will be very nice if you can do such analyzer precisively
igor