Is this a good wing loading?

[RC Storick]

(Weight x 2304) ÷ Wing Area

60OZ ÷ 16= 3.75    3.75 x 2304 = 8640  ÷ 650 = 13.2923076

[Brett Buck]

(Weight x 2304) ÷ Wing Area

60OZ ÷ 16= 3.75    3.75 x 2304 = 8640  ÷ 650 = 13.2923076

  Definitely in the ballpark.

     Wing area(sq inch)/144= wing area (square feet)

     Weight (oz)/wing area (square feet) = wing loading (ounces/square foot)

    650/144 = 4.51 square feet
   60 oz/4.51 square feet=13.29 oz/square foot

    I think this is more straightforward (the factor of 2304 = 16*144) but its the same end result. There's no reason to convert it to pounds, then convert it back to ounces (by using the factor of 16).

    Brett

[RC Storick]

Just the guy I wanted to look at it. Thanks for the reply. I know there is all kinds of ways to do things the problem is my math skills are elementry and this was how I know how to do it. I knew the answer was correct I just wanted to know if that was a good wing loading? It could go up a tad if I pork it up with clear but I am planing on a ounce of clear and call is quits.

[Brett Buck]

Just the guy I wanted to look at it. Thanks for the reply. I know there is all kinds of ways to do things the problem is my math skills are elementry and this was how I know how to do it. I knew the answer was correct I just wanted to know if that was a good wing loading? It could go up a tad if I pork it up with clear but I am planing on a ounce of clear and call is quits.

   Converting yours to mine

  weight (ounces)*144/wing area (square inches) = wing loading

   60*144/650 = 13.29

    Another ounce or so for clear, and assuming that is with battery, it's about the same wing loading as mine, when I enter the hourglass.

     Brett
   

[RC Storick]

  Converting yours to mine

  weight (ounces)*144/wing area (square inches) = wing loading

   60*144/650 = 13.29

    Another ounce or so for clear, and assuming that is with battery, it's about the same wing loading as mine, when I enter the hourglass.

     Brett
  

This includes battery and 1.5 OZ of wing tip weight, which could go up or down depending. So bench trimmed less clear. 59.02 OZ. Still seems quite nose heavy to me but I will fly it first and then if need be change the spinner to a lighter one, But I sure would like to use my $90.00 true-turn spinner. If that's not a joke the $55.00 a gallon thinner is. However its still $15.00 a quart for dope at Wicks. That's a deal I think, I just wish it was still AeroGloss red label.

[Doug Moon]

(Weight x 2304) ÷ Wing Area

60OZ ÷ 16= 3.75    3.75 x 2304 = 8640  ÷ 650 = 13.2923076

Robert? What is that 2304 and where did it come from?

[John Cralley]

I forget who sent me this chart last year but you may find it useful.

My Bad.  Forget the chart!!! It must date back to the fifties. I should have taken a look at it before I posted it!! 

[RC Storick]

Robert? What is that 2304 and where did it come from?

Can't remember but it works

[RC Storick]

I forget who sent me this chart last year but you may find it useful.

Well according to this chart my plane would have very heavy wing loading. Sorry but I don't believe your chart.

[Dave_Trible]

I think the chart was written in Fox .35 speak, a little out of date...and Time Marches On!

Dave

[Brett Buck]

Robert? What is that 2304 and where did it come from?

   2304 = 16 *144. He converts the weight to lbs by dividing by 16, then back to ounces by multiplying by 16, then converts the wing area from square inches to square feet by inverteing it and multiplying by 144 (12^2) That was my point above, the first conversion to lbs was unnecessary, the 16 of the (16*144) just converts it back to ounces.

   weight*144/wing area = wing loading in ounces/square foot if you start with ounces and square inches.
    Brett

[RC Storick]

   2304 = 16 *144. He converts the weight to lbs by dividing by 16, then back to ounces by multiplying by 16, then converts the wing area from square inches to square feet by inverteing it and multiplying by 144 (12^2) That was my point above, the first conversion to lbs was unnecessary, the 16 of the (16*144) just converts it back to ounces.

   weight*144/wing area = wing loading in ounces/square foot if you start with ounces and square inches.
    Brett

 now I understand thanks

[Brett Buck]

I forget who sent me this chart last year but you may find it useful.

    Dave has it right. Almost every NATs winner in the last 25 years is near or off the right side if the chart, some WAY off. This chart is mostly OK if you are only using vintage 4-2 break motors.

    Brett

[FLOYD CARTER]

You have calculated wing loading to 9 significant figures.  I'm amazed at your precision!
F.C.

[RC Storick]

You have calculated wing loading to 9 significant figures.  I'm amazed at your precision!
F.C.

Well that was close but it really is 13.29230769230769 not that it matters give or take a ounce. 

[Tim Wescott]

You have calculated wing loading to 9 significant figures.  I'm amazed at your precision!
F.C.

C'mon, Floyd.  He already admitted to having elementary math skills.

(Floyd is tweaking you for a Scientist Thing: the number of digits behind the decimal place is a scientist's way of saying how closely he knows the number.  13.29230769 in "scientist" means that you're claiming to know the wing loading to +/- 0.000000005 ounces/sq-ft.  Given how accurately you can measure the wing dimensions, and how much you're having to approximate when you take the tips into account, saying "13.3" probably states your case better, or even "about 13").

[RC Storick]

C'mon, Floyd.  He already admitted to having elementary math skills.

(Floyd is tweaking you for a Scientist Thing: the number of digits behind the decimal place is a scientist's way of saying how closely he knows the number.  13.29230769 in "scientist" means that you're claiming to know the wing loading to +/- 0.000000005 ounces/sq-ft.  Given how accurately you can measure the wing dimensions, and how much you're having to approximate when you take the tips into account, saying "13.3" probably states your case better, or even "about 13").

Its close enough if it flys

[Mark Scarborough]

Tim, refresh my memory,,

the KNOWN accuracy is + or - one-half the last decimal more than the least places you have in your measured quantities

so if you have measured quantities of 2 decimal places, then your answer is valid to +or- .005?

just curious, its been awhile since college class

[jfv]

I find comparing cubic wing loading is a better criteria than the squared wing loading.  It tends to give a better correlation of performance over different size airframes.  The cubic wing loading for your plane is 6.3, with a standard wing loading of 13.3.  For comparison, an airframe with a wing area of 500 sq. inches would have to weigh about 41 oz, with a standard wing loading of 11.8 to have the same 6.3 cubic wing loading.  Kind of explains why smaller planes need to be significantly lighter than their larger counterpart.  Your cubic wing loading of 6.3 is on the lighter side.  Should fly great.

Here's a link to a cubic wing loading calculator.

http://www.ef-uk.net/data/wcl.htm

[Tim Wescott]

Tim, refresh my memory,,

the KNOWN accuracy is + or - one-half the last decimal more than the least places you have in your measured quantities

so if you have measured quantities of 2 decimal places, then your answer is valid to +or- .005?

just curious, its been awhile since college class

I pulled the +/- 0.5 out of my ear, but since you asked I checked Wikipedia which is usually pretty good on scientific details.  They don't actually say, but they do cite a paper saying it's really hard to pin down just exactly how you should set the number of significant digits.

Generally, though, if you have a measured quantity of 2 decimal places then that should mean that the answer is valid to +/- 0.005, or 0.01, or 0.02, but certainly not 0.0001.

If it's really important, most engineers and scientists will state the precision exactly:  "3.14159 +/- 0.00002" or some such.

[Doug Moon]

My wing loading on last years plane was 13.66 dry, 15.35 full of fuel. I just added the 8oz of fuel to the total.

I based that on a 685 sqr inches and 65 oz. I think that is the area.  I used cad to determine it. If I measure it by hand it's more like 705 do the loading would be much less.

[Mark Scarborough]

I pulled the +/- 0.5 out of my ear, but since you asked I checked Wikipedia which is usually pretty good on scientific details.  They don't actually say, but they do cite a paper saying it's really hard to pin down just exactly how you should set the number of significant digits.

Generally, though, if you have a measured quantity of 2 decimal places then that should mean that the answer is valid to +/- 0.005, or 0.01, or 0.02, but certainly not 0.0001.

If it's really important, most engineers and scientists will state the precision exactly:  "3.14159 +/- 0.00002" or some such.

thats what I was trying to state, thanks

[RC Storick]

Pie R round cornbread R square

[Douglas Ames]

I find comparing cubic wing loading is a better criteria than the squared wing loading.  It tends to give a better correlation of performance over different size airframes.  The cubic wing loading for your plane is 6.3, with a standard wing loading of 13.3.  For comparison, an airframe with a wing area of 500 sq. inches would have to weigh about 41 oz, with a standard wing loading of 11.8 to have the same 6.3 cubic wing loading.  Kind of explains why smaller planes need to be significantly lighter than their larger counterpart.  Your cubic wing loading of 6.3 is on the lighter side.  Should fly great.

Here's a link to a cubic wing loading calculator.

http://www.ef-uk.net/data/wcl.htm

This is new one on me. Never heard of "cubic wing loading".

[Brett Buck]

This is new one on me. Never heard of "cubic wing loading".

  It appears unique to the modeling world. It may have some ad hoc reality to it, but it is not a term normal used in aeronautics. More or less its trying to account, very crudely, for scaling effects.

    Brett