Nice chart! Thank you for that!

And what timing, I was doing this just today actually, because I'm cutting my wings down to 24" each side. Yes, for a better scale outline.

OK, thing is this, and has been an ongoing question.

"Do you consider the "area" that's the fuselage?"

On some models, Jets especially, this can be considerable!

Here's a "chunky," just to show an example.

I have 8" of fuselage eating up my wing area! Actual scale would be 9".

Span, 48"
Root cord, 11.5"
Tip cord, 7.75
Fuselage thickness, 8"

I figured my Sq's out and I'll bet I'm wrong. Those four measurements will give you my wing area.

I could use the help, so what do you get?

Thanks in advance.

Charles

Hello avaiojet,

This topic of including or not including the fuselage in the lift area has been discussed in the past adinfinitum.

As I recall there was no definite conclusion reached.
The thead became one of "forum politics" more than analytical.

Some judgment has to be used based on the type of fuselage involved.
If the width of the fuselage is less than 10 to 12% I do not include its width in the wing span as one factor of calculating the wing area.

If the fuselage width is more than 12% but less than 25% I tend to calculate using both meaning with and withouot the fuselage width and compare the difference. It is often difficult to figure out if the fuselage has an appreciable lift factor. It can be either way versus the main wings.

When considering a "delta wing design" which, most of the time has a high leading edge sweptback I include the fuselage as part of the lifting surfaces. That seem to be realistic and make sense to me.
I try to evaluate the contribution of the fuselage part of the lift forces.

These days the power to weight ratio is more important than the wing loading.
Nearly all modelers equip their model with an engine/prop assembly that provides moe thrust than the the model weigh.

It is easy enough to calculate both ways using your posted figure.
I suppose that by "fuselage thickness" you mean the width of the fuselage in the wingspan direction.
When including the fuse in the area I would consider the chord of the wing to be the same as the root across the fuse.

Zor

Zor brought up that old thread, it's true, it just went on and on without one firm answer. Loading is measured as your wing area and the weight of the plane, that's why the chart is so easy. The wing span is measured tip to tip and the fuse isn't measured in. Here is an 80 span plane with a big fuse, the fuse isn't counted in the span or area. You make up your own mind. It is a one piece wing so when I remove it then it's still got the same span and area. My thinking about wing loading is, it is what it is and I don't worry about it. It gives you a general idea of it's stall speed and landing speed. Heavy small wing warbirds have a high wing loading and they tend to stall faster at lower speeds. What you going to do about it other then fly and land a bit faster.

Thank you gentleman,

I knew nothing about that other Thread. Can't be everyplace and, as you said, it was a while ago.

Yes, the measurement would be the cord at the fuselage. Good point.

In my particular case, 8" is plenty of fuselage and I would subtract that area from the total. Certainly my WL will be higher, but better to have a correct figure.

And yes, power does it all and a long take off roll!

Thanks guys, I appreciate the reply and the input.

Charles

Guys long ago the full scale convention was to include any area covered by the fusealge just to keep the computations simple and to have one standard.

In your discussions here you've already implied that now we need yet another standard to determine at what point do we include or disallow the area under the fuselage.

Then take a more extreme example, both the F-4 and the F-106 have "coke bottle" fuselages, do you do the caluculs to determine the exact area of the curved wing surface that occupies the open area created by the coke bottle curve?

The A-4 Skyhawk has inlet duct overhanging the wing to body area. Is that portion of the wing lifting or not? Do I count it or not.

Remember the purpose of wing area is to give you a number to work from, it is a generalization. You are aparently trying to apply a micrometer to an inexact number.

MYC YMMV

Tom S
Aero Engineer

No I'm not. I believe you are, by reading more into this than was expected.

My question was quite simple, even for an engineer to understand.

Make out of this whatever you want?

There just model airplanes.

No one has mentioned what my Sq's are?

AMF

Charles

That's why Zor mentioned the last post, it can go one and on. It's just your wing area and the weight that gives the loading. Nothing to be deep thinking about and wing loading on a model tells you something but not much. Once in a while I will see what the loading on a plane may be just for grins, I know someone will ask at some point but most the time it's something I give no thought to at all during a build. There are more factors involved that I think about, I'm a stinker when I do incidence and CG but I know guys that are into these things way more then I am.

Gray,

Yes, I too set a model up as correct as possible. I have never, never been concerned with weight.

Until now with this Jet project.

I see those large EDF battery packs, and as many times as I've asked, I still haven't been told their weight?

Charles, I know less then spit about jets and maybe a bit less then that about electrics. When I need info for an electric of any type I go over to the wattflyer forum and get some good info.
My new plane floored me. There is nothing in the plane, zero, zip but I was asked about the added weight of the Deft Sanding Lacquer so I hung the plan on my scale, so far just the wood and glues came out to 6 pounds so even with an old Brison 40 in it it should come out light. Unless I get stupid with the paint gun. Been known to happen!!

Gray,

Thanks for the reply.

Funny, I don't know Jack spit about Jets either, but I am a model builder. All the same but different.

Wattflyer? OK, that's a new one. Is this where all the electric guys hang? Google?

Got a photo of your project?

Bottom of the header bar here on RCU will get you right there, your just a click away.

Gray,

Hey! Is that a clue? I'm not gifted, exactly what does that mean?

You do have a GB.

So what did your wing loading come out at?

Bob

Right on this thread up top it says Airplanes and were in Kit Building, click onto the blue airplanes then go to the bottom of the page, there you will find wattflyer.com

OK. Not trying to be picky, but my brouwser doesn't show any "blue airplanes", either in graphics nor text.??????

Les

Bob, thanks for the question and reply.

I'm waiting to see what "others" come up with?

Yes I know, I have a long weight.

I just cut my wing down, I'll save some weight there.

Did you see my gag photos?

When you log onto RCU and you are scrolling down to find kit building just keep scrolling down to the bottom of the page, wattflyer is there. Or just google it.

Major,

With all due respect, I've implied nothing. I simply asked a question. My suggestion would be that you re-read my original Post.

Thanks for the reply and thank you for your comments.

Hi Tom and all readers,

I do not see any problems with having more than one method of figuring the wing loading if we know which standard is in use.


I even have doubts about the validity of any method in these modern times.
With delta wing designs and all kinds of stuff hanging under the wings or at the wing tips such as extra fuel tanks, bombs, missiles and with the high thrust of powerful engines, the wing loading becomes irrelevant.

The importance these days particularly for modelers is the "thrust to weight" ratio.
I was at the flying field yesterday with my new "Radian pro sailplane". A machine that really flies "so called 'on the wings' while all otherfliers had models that could climb straight up vertically and flew "so called on the engine" .

My next post will show the calculations based on the dimensions given in the first post.

Wishing that all readers enjoy their flying.

Zor

All readers,

Span 48"
Root chord 11.5"
Tip chrd 7.75"
Fuselage 8"

Each wing has an area of 192.5 sq. in.
Fuselage has an area of 92 sq. in.

Total wing area NO fuselage is 385 sq. in.
Total areas WITH fuselage is 477 sq. in.

Take your pick _ _

Zor

Zor,

Thanks for that,

I got 462 for total SQ's, not counting the fuselage.

Hi All,

Anyone kind enough to take a moment to point out my error ?

Zor

Zor,

Why are you so quick to think it's your error? I make mistakes too. Well.

I don't bother with that kind of "real" math.

I added 11.5 to 7.5 then multiplied it times the span then devided by two.

Hi again Avaiojet,

I first calculated in maths only since I had not seen a figure in the thread.

When I saw a different answer I went to software that can draw and calculate for me.
So I printed it, scanned it and posted the drawing.

I was not "so quick to think it was my error". It takes time to draw this up, print it and scan it to get a ".jpg" picture to post.

I am a "slow poke" .

Best 2 U de Zor.

Zor,

Well, you did do a great job in getting that on line. Your efforts are appreciated.

Hey! You got the L-39?