Why does wingloading go up in bigger planes?
09-23-2004 | 03:29 AM
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From: Ironhorse,
WI
Why does wingloading go up in bigger planes?
As I have been collecting data on planes into Excel, I am noticing that larger planes have higher wingloading. Of course there are exceptions, but there is a definite trend.
For example:
U-Can-Do 46 at 5.5lb and 904 in^2 is a wing loading of 14oz/ft^2
H9 FuntanaS 90 at 9 lbs and 1107 in^2 is a wing loading of 19oz/ft^2
CH Vision 3D at 14 lbs and 1300 in^2 is a wing loading of 25 oz/ft^2
H9 33% Edge 540 is 23 lbs and 1730 in^2 is a wing loading of 31 oz/lf^2
Is this simply because as scale (size) increases, the volume (sort of mass) goes up by the cube of the increase and the area only goes up by the square?
ie. take a sheet of material, 10"x10"x1". Volume = 100in^3 , area(flat ways) = 100 in^2 so Volume to Area is 1
double it's size (all 3 dimentions) to 20"x20"x2, Volume = 800in^3, area is 400in^2 so Volume to Area is 2 (hence higher wing loading?)
For example:
U-Can-Do 46 at 5.5lb and 904 in^2 is a wing loading of 14oz/ft^2
H9 FuntanaS 90 at 9 lbs and 1107 in^2 is a wing loading of 19oz/ft^2
CH Vision 3D at 14 lbs and 1300 in^2 is a wing loading of 25 oz/ft^2
H9 33% Edge 540 is 23 lbs and 1730 in^2 is a wing loading of 31 oz/lf^2
Is this simply because as scale (size) increases, the volume (sort of mass) goes up by the cube of the increase and the area only goes up by the square?
ie. take a sheet of material, 10"x10"x1". Volume = 100in^3 , area(flat ways) = 100 in^2 so Volume to Area is 1
double it's size (all 3 dimentions) to 20"x20"x2, Volume = 800in^3, area is 400in^2 so Volume to Area is 2 (hence higher wing loading?)
09-23-2004 | 12:39 PM
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From: Wayne,
NJ
RE: Why does wingloading go up in bigger planes?
I believe it's due to whats called "scale effect" has to do with reynolds numbers. On a small 30 inch span electric a wing loading of 15 oz/sq ft is high. On a 50 inch span 40 size plane it's low. On a 1/4 scale 35's considered low.
Mike
Mike
09-24-2004 | 02:24 PM
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From: Clarks Summit, PA
RE: Why does wingloading go up in bigger planes?
Your comparing different wing designs. To get a truer picture, pick one wing design, in different sizes. Off hand, the plane with a varied range in sizes that comes to mind, is the Lanier Stinger, It comes in a .10, maybe a .30 or .40, there is a .60, a .120 and finally a giant scale. Now you have apples to apples. Good luck, Joe
09-24-2004 | 09:34 PM
#5
RE: Why does wingloading go up in bigger planes?
It is apparent that the efficiency of lift goes up with size. It may help to think of it as; collectively the air molecules can provide better support as the airfoil increases in size. Try to envision something on sand...as the base increases the better the support.
09-24-2004 | 10:02 PM
#6
RE: Why does wingloading go up in bigger planes?
Just to add more to the mental model...as size (area) goes up so does the Effective viscosity relationship with the airfoil. I hope that helps
09-25-2004 | 08:36 AM
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From: St. Martinville,
LA
RE: Why does wingloading go up in bigger planes?
The real determining factor is not wing loading, its cube loading. I will post an explination and formula later. I don't remember it off hand but I know the cube loading thing works.
Ryan
Ryan
