How do you figure wing laoding?

[Bigrc2]

It might be a stupid question. But I never had to figure it out before!! So I need to know how to figure a bipe and a single wing!! Thanks in advance!! Bigrc2

[Shortman]

http://gsal.org/

go to tools, wingloading calculator


Don't work to hard heh heh.

[Bigrc2]

Thanks buddy, I have no intention too!! :D :D

[Bill Mixon]

That GSAL site is just a bit off. It's right if you replace the "OZ per SQIN" with "OZ per SQFT". :)
Or you could calculate it with a simple calculator or paper and pencil.
First you have to figure out what unit(s) you want it in.
An example
If we have a plane that weighs 8 oz. with 320 sq" of area you can simply divide the weight by the area (8/320=.025). That's the oz. per sq". now if you want that in oz per sq' (FT) muliply .025 X the # of sq inches in a sq foot (144) .025X144=3.6oz per sqft

[surfimp]

It might be a stupid question. But I never had to figure it out before!! So I need to know how to figure a bipe and a single wing!! Thanks in advance!! Bigrc2

Wing Area = Wingspan Length x Average Chord Width

Average Chord Width - use the average of the tip and root chord distances. If you have an 8" root chord and 4" tip chord, your average chord is:
8 + 4 = 12
12 / 2 = 6" average chord

Normally wing area is expressed in square inches, but wing loading is expressed in ounces/square foot for whatever reason. There are 144 square inches in a square foot, so to calculate wingloading all you need to do is:

Square inches of wing area / 144 = Square feet of wing area

Square feet of wing area / all up weight in ounces = wingloading in ounces per square foot

If you have two wings, do calculations for each wing and add them together. The sum is your total wing area, which you can then use to calculate wingloading.

Steve

[Bigrc2]

Ok Bill here anouther stupid question. On my mini tansor I come up with .0217. How do I convert the decmal point into regular ounces?

[Bigrc2]

Also what is considered good wing loading on a slow flying 3D plane?

[surfimp]

Also what is considered good wing loading on a slow flying 3D plane?

That's going to be partly a function of the size of the plane. In general, the smaller the plane, the lower you're going to want the wingloading to be. Larger planes can tolerate higher wingloadings without degraded performance.

In my rather limited experience, I find that for 3D planes less than 30" in wingspan, you'll want to get your wingloading to 5oz/sqft. or less. 4oz. is even better.

The higher wingloading planes can fly just fine in a small scale, but they will be flying faster, so when you crash they'll be hitting harder. That can translate into a great amount of damage. Lightweight is good for many reasons, not least of which is durability.

Steve

[Bill Mixon]

That's what it is in ounces, it's way less than 1 oz. .0217 oz. Now multiply that by 144 and you have 3.1248 oz. Sqft.
That's if you divided your weight in oz by the wing area in sq inches.
Does that make sense?
Also what is considered good wing loading on a slow flying 3D plane? That depends on the size of the plane among other factors. A big plane might float around very light and 3d just fine at 15 oz per sq ft, but a much smaller plane of the same design would be a total brick at that wing loading.
For example if you have a plane that does great at it's weight and you decide to make a version half the size of the original and have it end up at half the weight it won't fly as well.
There are calculations you can do to figure optimum loadings for different sizes, but that is sort of complex.

[Bigrc2]

Thank you very much guys! You helped me out quit abit!! So my Mini Tensor with a 17.5" ws with a wing area of 183.75 sqin at 4oz. Has a wing loading of 3.12 oz. Sqft. Do's that sound decent to you!! Just to give me an idea or a comparson for similar prodjects!!!

[Bigrc2]

Ok, I just measured up my mini sorta tensor. At a 20.75" ws at 6oz. It has a wing loading of 3.20oz. Sqft. So correct me if I'm wrong but the 17" Tensor's Wing loading could be better. So if I can get that in the mid 2s. That would be great!!

[Bill Mixon]

I did some calculations, and mid 2's would be awesome. I think that's a little aggressive though. From what I come up with (I'm not 100% sure about this) you should be good at 2.8 oz sqft.

I'm curious as to how your two planes compare in flight. I guess the 20.75" flies a noticeable amount better than the 17.5" version??

[Bigrc2]

I dont have the 17" done yet! I'm waiting for the motor! But I think I'm going to frame up another one and go for the mid 2's! I was crunching some numbers last night and I'm pretty shure it canbe done or come darn close!! I 'll keep you informed on the progress as soon as I get the motor!!

[biber]

Normally wing area is expressed in square inches, but wing loading is expressed in ounces/square foot for whatever reason.
Steve

That's why im so happy using the SI-units :D . It makes things less complicated. To get to kg/m² from g/dm² I only have to shift the decimal one digit to the left and that's it! :p

No faktors like 144 or 12 or whaterver for unit hopping, always just 10^n => shifting the decimal n digits to the left or to the right. Can't believe that there even are engineers still using anything else than SI-units. Maybe they don't want to depend on an "Urmeter" that is stored in Paris, France. ;) :D :D