What is wing loading?

[swik]

Hi everybody

what i would like to know is:

what is wing loading?
is it the ratio of wing area to weight?
how do you work it out?

Thanks

[perttime]

You've got it about right. You divide the weight by the area.

[swik]

Thanks for the reply

So does a low wing loading make a plane floaty?

[CloudyIFR]

If you use the American system wing loading is model weight in ounces divided by wing area in square inches times 144.

Model Weight = 55 ounces
Wing Area = 1440 square inches
Wing Loading = 5.50 ounces per square foot.

So each square foot of wing area is supporting 5.5 ounces.

If you have MS Excel download Sailplane Calc which will easily calculate Wing Area among many other very complex calculations.

Soon, as in a few months, I'll write a tutorial for the spreadsheet.

http://h1.ripway.com/cloudyifr/files.htm

Curtis
Montana

[Flyingwingbat1]

Thanks for the reply

So does a low wing loading make a plane floaty?

Yeah, lower wing loading = slower stalling speed. Stall speed is proportional to the square root of wingloading. If you increase wingloading 4x, the stall speed rises about 2x, assuming the airfoil behavior doesn't drastically change with speed.

[BMatthews]

A low wing loading makes the model able to fly more slowly. But if it's a clean design with low drag and lots of power a lighter model will also fly faster than a heavy model. A win-win situation.

[Cory]

A low wing loading makes the model able to fly more slowly. But if it's a clean design with low drag and lots of power a lighter model will also fly faster than a heavy model. A win-win situation.

The answer actually depends on what you're designing. If you're designing a glider, that's not necessarily true. Since gravity is the gliders "motor", you need some weight go get it going. As an extreme example, imagine a glider that weighed nothing. It would not be able to glide since it would have no "motor". It would just sit there and bounce around with the air currents, very much like a hot air balloon. On the other extreme, look at the Dynamic Soaring gliders. The new world record was just set yesterday at 313 mph. The fast DS planes are pretty heavy.

[vintage1]

Or to put it another way, a lighter model will fly faster under power, and slower on the glide. All other things being equal.

[Texas Buzzard]

Wing Loading

In full-scale aircraft the wing loading is given in pounds per square foot.

In models we use ounces per square foot. Europeans are different, they use metric syst.

Find the number of square inches & divide by 144 sq. inches/sq, ft. This gices you the area in feet squared.

Now divide the weight in Ounces by the number of sq. feet. This equals the wing loading. :) If you were to add some fishing sinkers to your plane the velocity at which your plane would stall will go up because the wing loading went up.

[Brandano]

Europeans are different, they use metric syst.
European and pretty much the rest of the world as well, and it's a big world, believe me :)
This reminds me of a nice anecdote, from a book called "How to be an alien", a cute booklet written by an Hungarian guy living in the UK. He was at a party, and a lady that had a glass too many asked him if he'd marry her. He replied "Gosh, I don't know. I think my parents might object to me marrying a foreigner." . Her reply: "What do you mean a foreigner? You are a foreigner, I am British!" which in my eyes sums up the British mentality really well.

[macboffin]

Wing Loading

In full-scale aircraft the wing loading is given in pounds per square foot.

In models we use ounces per square foot. Europeans are different, they use metric syst.

Find the number of square inches & divide by 144 sq. inches/sq, ft. This gices you the area in feet squared.

Now divide the weight in Ounces by the number of sq. feet. This equals the wing loading. :) If you were to add some fishing sinkers to your plane the velocity at which your plane would stall will go up because the wing loading went up. But, strangely enough, the glide angle would stay the same, ie L/D the same, although the plane would glide down that same slope faster.(Assuming those fishing sinkers were not outside, adding to drag!).

[Ricardo RW]

Mass over area is pressure, isn't it? As far I remember from physics when I was at the university (loooong time ago...)

[Flyingwingbat1]

Mass over area is pressure, isn't it? As far I remember from physics when I was at the university (loooong time ago...)

Close, it's FORCE over area. In any case, I think we covered "what is wingloading?" pretty throroughly, no? :)

[BMatthews]

The answer actually depends on what you're designing. If you're designing a glider, that's not necessarily true. Since gravity is the gliders "motor", you need some weight go get it going. As an extreme example, imagine a glider that weighed nothing. It would not be able to glide since it would have no "motor". It would just sit there and bounce around with the air currents, very much like a hot air balloon. On the other extreme, look at the Dynamic Soaring gliders. The new world record was just set yesterday at 313 mph. The fast DS planes are pretty heavy.

Very true that. I admit I was thinking more about the powered models.