what does this term mean?

It is simply the amount of weight each square foot of wing surface must carry. If you had a ten pound airplane with ten square feet of wing area, the wing loading would be one pound per sq. ft. It's usually given in ounces for our models. A sailplane may have a wing loading of 10 or 12 ounces, where a scale warbird's loading may well be over 30 ounces. Just divide the weight by the wing area.

Weight of the plane divided by sq. inches of the wing area.

a 12.5 lb plane (200oz) with a 100sq inch wing will have a wing loading of 2 oz per Sq inch.

Also these could be of some help.

There's 16 ounces in a lb. And there's 144 sq. in. in a sq. ft.

So figure your area by multiplying span by chord. Ex. 12"chord 48" wingspan = 576 sq. in. Now divide by 144 to get sq.ft. which equals 4 sq. ft.

Then figure your weight in oz. So lets say 3 lbs 9 oz. 3x16 = 48 oz. added to 9 oz. = 57 oz.

Now that you have those two numbers you can find your wingloading in oz./sq.ft. Which would be 57 oz. divided by 4 which comes to 14.25. So your wingloading is 14.25 ounces per square foot.

Hope that made it simple.

Josh

MinnFlyer,

Your calculation is correct, but that's 288oz/sq ft. That one won't fly, unless you're going about 150 mph!

Wouldn't it be nice if the wing loading was expressed in the same units as the plane's units?

When was the last time you saw a plane spec like this:

Wingspan 7.5 feet
Wing Area 7.80 sq ft
Weight 175 oz

Or when did you ever see?

Wing loading: .00980 lb/sq in

:-/

I think we're so used to ounces per square foot we'd have to do a conversion before we'd have any idea what our wing loading was! I know I have to mentally convert kilometers to miles before I can get a feel for how far it "really" is. I also tend to convert ounces to pounds if the ounces get much over 60 or I'm lost. Tell me a plane weighs 128 ounces and I've got to change it to eight lbs. Same with millimeters. I have to do a quick rough headspace conversion before I can sense a 12 mm something is a bit less than half an inch. I wish I'd grown up metric, as it IS much simpler!

If you grew up in the U.S. you DID grow up metric. 100 cents = 1 dollar.

mike james,
57/4=14.25, like minn said...
57*4=288, like you said...
it's oz/ft^2, not oz*ft^2, so minn was right...
just had to point that out

I was just using easy numbers to keep it simple.

One point here is the higher the number the more of a missle it will be and size does not matter. I had a Lanier Stinger 120. Wingloading was somewhere aroun 9 or 10. Although a large plane it floated around and also on landings. I have a little DC F-20 Tigershark with numbers in the 30's. It is a flying bullet with no glide ratio and lands hot and fast or you will stall and crash.

I find size DOES matter. The larger the plane, the higher the wing loading can be and still retain good flying characteristics in my experience. I can imagine the smaller Tigershark with a high wing loading would be quite a handful.

Yeh, I have watched them all fly to include my own. Turbines, DF, and props. Jets of any kind are no more than a flying brick. If that engine quits, everything else after that is luck.

Wing loading is of importance to some aircraft and not so important to others. For Jets and some WWII aircraft high wing loading is expected and is not a big issue. For gliders and sail planes, wing loading is very important and the lighter the better!

I find it rather amazing that a fully loaded modern fighter/bomber has a wing loading about like a manhole cover! (ok.. personhole for the politically correct?) Raw power overcomes a lot.

I think when it comes to full size then it's a matter of Reynolds numbers, sort of a scale affect. The bigger the wing the more efficient it becomes for the same air speed.

For models though I find that the lower the wing loading the better which is why I use quite large wings and build as lightly as I can (within reason ).

I have had a Extra with a 72 inch wing and I now have one with a 80 inch wing. Their weights were about the same but I find that the 72 inch flys and lands better and the 80 inch presents better when flying sequences. The difference is slight and could be attributed to the engine.