|Jul 31, 2010, 10:41 AM|
Joined Nov 2009
What's the difference between high and low wing loading?
I'm trying to find how to tell the difference between planes that have a high wing and low wing loading plane.
Could someone give me the name of a 3D plane that has each for an example or what to look for in the specs?
|Jul 31, 2010, 12:28 PM|
I'm no expert, but here's my best explaination.
Look for the "Wing Area" in the specs and the AUW (weight with everything ready to fly) which is usually in ounces. The wing area is usually given in square inches, so you take that info and divide it by 144 to get the square feet of the wing. You then divide the weight by the square feet to get the ounces per square feet.
The lower oz's per square feet the slower the plane will fly and will have a lower stall speed. For high alpha 3D you generally want as low a wing loading as you can get, even more so if flying indoors. Jet's and sport planes will usually have a higher wing loading and will fly much faster and require more speed to land.
Some planes, however, don't give you the wing area, but only the wing width. I just look at the taper and chord (depth) of the wing in that case and get a general feel for what the wing loading might be. I use a very rough formula for my outdoor 3D high alpha (somewhat floater) planes, 2 inches of wing for every oz. of weight max. For example on a 32" plane I shoot for a max of 16oz. For indoor you'd want to shoot for less weight than that (tighter area and no wind), more like a max of 12oz I would guess.
Here is an example plane spec:
Wing span: 32"
Wing chord: 9"
32X9=288 sq inches /144 = 2 sq ft
16 oz / 2 sq ft = 8 oz per square foot
All things considered this should be a pretty gentle flying outdoor 3D plane, though I would shoot for a lower wing loading for lighter wind conditions.
oh, forgot, if the specs are in Metric I convert them to standard.
|Jul 31, 2010, 12:34 PM|
Joined Nov 2008
Wing loading is the first thing I look for when I am going to build or buy a plane. Wing loading is defined as the weight in ounces per square foot of surface area of the wing.
If your plane has a wing 8 inches wide i.e. wing including ailerons, 30 inches long, it has an area of 240 square inches. A square foot has 144 square inches in it so if you divide 240 square inches by 144 you get 1.66 square feet.
If you build Leadfeather's Yak55 and put a "Blue Wonder" and a 500 milliamp 3s battery on it, you'll come up with an All Up Weight (AUW) of around 8 ounces. Divide 8 by 1.66 and you will come up with 4.8 oz per square foot of wing loading. This low figure means the Yak will be able to fly very slowly in a low wind enviornment and still stay in the air. If you look at any of Leadfeather's or Motorhead's videos you will see how slowly they can fly the plane and keep it airborne and do stunts. Sometime they can bring the airplane in for a landing against a mild breeze and pick it right out of the air.
When the plane gets heavier, and the wing area stays the same the wing loading will go up which means you will have to fly it faster to keep it in the air. When wing loading gets up in the double digits per square foot of wing area, you will have to have higher take off speeds and landing speeds to bring it in safely and it will hit a stall speed much more quickly than one with low wing loading. It will also be easier to fly in higher wind than one with low wing loading.
If you look at some of the models sold in the model airplane magazines, check out wing loadings and you will see that the thin profile foam models have a much lower wing loading than the full body models.
If you are new to flying rc, you should look for a high wing model with low wing loading so you can fly it slowly to build up your eye thumb coordination. once you don't have to think what to do, you can go to more glamorous models like the low wing fighters or jets and bring them home at the end of the day in one piece.
hankg... sorry, i didn't mean to reiterate khen's fine explanation. He must have hit the enter key a microsecond before I did.
|Jul 31, 2010, 09:17 PM|
Joined Nov 2009
Thanks,I understand.I have a high wing load on my plane and it doesn't like to do any high alpha flying,it'll hover,knife-edge but it won't harrier upright or inverted.
|Aug 03, 2010, 10:48 AM|
Joined Oct 2008
Hang on a sec, goldy. High wing loading is sometimes necessary to make a park jet go fast. Now, roberted5 specifically mentioned 3D, so low wing loading is a Good Thing® in that case. If he wanted to go fast then wing loading wouldn't be so bad, eh?
By the way, roberted5, you mention that your plane can hover and knife edge. How is it that you can't get it to do high AoA if you have enough zotz to make it hover? High alpha is dependent on power/weight ratio, not wing loading. At a certain level of throttle you are simply dragging the rest of the aircraft behind the prop. The control surfaces just keep it from moving around on its own.
|Aug 03, 2010, 06:26 PM|
Hey, I resemble that remark.
Heavy = more amps, shorter flights
Light = less amps, longer flight
Heavy = must fly faster to stay aloft
Light = can fly fast or slow
Heavy = more damage on impact
Light = laugh at your mistakes
|Aug 03, 2010, 07:13 PM|
wow! hankg thanks I learned something today!
I tried my first EDF exceed rc f-18, that thing is high wing loading, since it was my first EDF, I didn't know that you have to land it like a rocket, eased off the throttle, down it goes like a rock.
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