Wing Area on stunters

I have a number of reasons for this.
Firstly, it is difficult to come up with an accurate area for tips, even for the very simple tips I use.
Second, the wing area lost in the fuselage will usually come close to the area that should have been included in the tips.
Third, a few square inches one way or another is completely immaterial. You need to make big changes before they really become relevant - ST46 designs for example, range from 600 sq ins to over 700.

So, why do you need a wing area? For no other reason than to get an idea of size. It does not give you a definative answer on size - add half an inch to the depth of your fuselage and watch the drag go through the roof for example. The perfect wing loading is completely immaterial too because you always build as light as you can (no one is going to add balast to bring the weight up to a wing loading) and once the model is being used, it is generally gaining weight anyway.

So the wing area gives only a guide for comparison - the real comparison comes in the air.

I design all my models, and I need a simple method of gaining that size comparison. My design spreadsheet automatically gives me the wing area based on average chord x span without tips. It also gives the aspect ratio. Using these four, I fiddle with the numbers to give the other numbers I'm aiming for, and the wing design grows out of that.

But at the end of the day, absolute wing area, whatever that is, is a relatively meaningless number.

Besides which, modellers are notoriously lousy at maths, measuring and recording, which is the real reason the areas shown on plans are never correct.

It's still a good question. Given the ease with which you can use CAD programs to establish a very close approximation of the area contained within quite complex shapes, a difinitive answer would be nice.

The
>perfect wing loading is completely
>immaterial too because you always
>build as light as you
>can (no one is going
>to add balast to bring
>the weight up to a
>wing loading) and once the
>model is being used, it
>is generally gaining weight anyway.
>

Just wanted to point out that this isnt exactly true as a generality.

Sailplanes (model and full-scale) routinely add ballast for certain mission profiles. Wing aerodynamics being what they are, do suggest a narrow range of wing loading for optimum performanace.

I believe I have read some of Windy's reviews that indicate better PA performance in breezy conditions when certain planes became a little heavier.

But It would certainly be alot better to build it light and then add ballast if needed than to have my situation..having to reduce!

FWIW

In most of life, there is no "they". We just imagine them. Figure squares the way you want, and that is the correct answer. Your answer does not have to agree with anyone's.

Unless it won't fit in your Yugo!

There are variances in a lot of kits, My Shark claims 687 Sq. In., but by actual calculations it has 676 total and 660 effective square inches. Effective being without the fuselage area included. My method is. Take from the tip ribs and measure length and then find the MAC flaps included and multiply. Get the plans and then draw a 1" X 1" Grid on one tip. Measure all the whole sq inches. Go back and estimate as closely as possible the total of the partial square inches on the grid. Multiply by 2 and add to the wing area. That's how I got my 676 on the Shark and 660 effective areas. So you can see there can be variances in how area is derived and what the exact total might be. Eliptical wings prove to be even more difficult that straignt tapers.

I think that almost all magazine plans are drawn by someone other than the original designer. If they get it somwhat close then the designer says O.K. so that they can get the article into print. I would almost bet that no magazine aritcle plans exactly match the original model. Even if the original designer does draw the plans as GMA did, they could and did take some liberties from what their original was - either from loss of memory, or on purpose. Example, the Jetco, MAN and RSM plans for the Shark .45 are all quite different from one another. The Real Shark .45's had two or three different configurations. Basic overall appearance to the 62 version is pretty similar, but that's about all that's the same.

P.S.

Wouldn't it be a little easier for you to pick up the phone and call me at work - 313-6200!

Now, who is to say that the original plane is the "perfect" design and that the slight differences are going to hurt, not help. Truth is, Most any variant of the Shark will fly about the same and most any variant of the Nobler will fly about the same (except for the Gieseke Nobler which has a thicker airfoil, different moments, etc.). The biggest difference on all of these will be weight ahd power plant and set up and....but not which set of plans you used.