function updateLabels() {
var unit = document.getElementById('unitType').value;
var weightLabel = document.getElementById('weightLabel');
var areaLabel = document.getElementById('areaLabel');
if (unit === 'imperial') {
weightLabel.innerText = "Aircraft Weight (lbs)";
areaLabel.innerText = "Wing Area (sq ft)";
} else if (unit === 'metric') {
weightLabel.innerText = "Aircraft Weight (kg)";
areaLabel.innerText = "Wing Area (sq m)";
} else if (unit === 'rc_imperial') {
weightLabel.innerText = "Aircraft Weight (oz)";
areaLabel.innerText = "Wing Area (sq ft)";
}
}
function calculateWingLoading() {
var weight = parseFloat(document.getElementById('aircraftWeight').value);
var area = parseFloat(document.getElementById('wingArea').value);
var unit = document.getElementById('unitType').value;
var resultDisplay = document.getElementById('finalResult');
var container = document.getElementById('resultContainer');
var textDisplay = document.getElementById('interpretation');
var badgeDisplay = document.getElementById('categoryBadge');
if (isNaN(weight) || isNaN(area) || weight <= 0 || area <= 0) {
alert("Please enter valid positive numbers for both weight and wing area.");
container.style.display = "none";
return;
}
var loading = weight / area;
var unitText = "";
var classification = "";
var badgeClass = "";
var description = "";
// Determine units and logic
if (unit === 'imperial') {
unitText = "lbs/ft²";
// Rough classifications for Full Scale
if (loading < 10) {
classification = "Glider / Ultralight";
badgeClass = "wl-badge-glider";
description = "This indicates a very light aircraft capable of flying at low speeds. It will be very susceptible to wind and turbulence but will have excellent gliding ratios.";
} else if (loading < 25) {
classification = "General Aviation / Trainer";
badgeClass = "wl-badge-trainer";
description = "Typical for Cessna 172s or Piper Cherokees. Offers a balance between stability, stall speed, and cruising performance.";
} else if (loading < 50) {
classification = "High Performance / Light Jet";
badgeClass = "wl-badge-sport";
description = "Higher landing speeds required. Smoother ride in turbulence due to higher wing loading.";
} else {
classification = "Commercial / Military Jet";
badgeClass = "wl-badge-jet";
description = "Requires long runways and high takeoff/landing speeds. Very stable in flight.";
}
} else if (unit === 'metric') {
unitText = "kg/m²";
// Metric classifications (Approximate conversions)
if (loading < 50) {
classification = "Glider / Ultralight";
badgeClass = "wl-badge-glider";
description = "Low stall speed, high thermal efficiency. Susceptible to wind.";
} else if (loading < 120) {
classification = "General Aviation";
badgeClass = "wl-badge-trainer";
description = "Standard performance for GA aircraft. Balanced handling characteristics.";
} else {
classification = "High Performance";
badgeClass = "wl-badge-jet";
description = "High speed cruise, high landing speed, requires longer runways.";
}
} else if (unit === 'rc_imperial') {
unitText = "oz/ft²";
// RC Plane Classifications
if (loading < 10) {
classification = "Glider / 3D Flyer";
badgeClass = "wl-badge-glider";
description = "Very floaty. Can fly slowly without stalling. Great for indoor flyers or thermal soaring.";
} else if (loading < 20) {
classification = "Trainer / Sport";
badgeClass = "wl-badge-trainer";
description = "The sweet spot for most RC pilots. Handles some wind but lands at a manageable speed.";
} else if (loading < 30) {
classification = "Warbird / Speed";
badgeClass = "wl-badge-sport";
description = "Flies fast and lands hot. Requires good throttle management and pilot skill.";
} else {
classification = "Scale Jet / Heavy Scale";
badgeClass = "wl-badge-jet";
description = "Very high stall speed. Must keep speed up in turns to avoid snap stalls.";
}
}
// Display results
resultDisplay.innerHTML = loading.toFixed(2) + ' ' + unitText + '';
badgeDisplay.innerHTML = '' + classification + '';
textDisplay.innerHTML = description;
container.style.display = "block";
}
Understanding Wing Loading
Wing loading is a fundamental concept in aerodynamics and aviation that relates the total mass of an aircraft to the surface area of its wings. Whether you are designing a full-scale aircraft, building an RC model plane, or simply studying flight physics, understanding this ratio is crucial for predicting performance characteristics.
The Formula
The calculation is straightforward. It is the loaded weight of the aircraft divided by the wing area:
WL = Weight / Wing Area
Common units include:
Imperial (Full Scale): Pounds per square foot (lbs/ft²)
Metric (Full Scale): Kilograms per square meter (kg/m²)
RC Models: Ounces per square foot (oz/ft²)
Why Wing Loading Matters
The wing loading value tells us how much weight each unit of wing area must support. This directly influences the aircraft's speed, maneuverability, and handling qualities.
1. Stall Speed
There is a direct correlation between wing loading and stall speed. Generally, a higher wing loading results in a higher stall speed. This means the aircraft must fly faster to generate enough lift to stay airborne. Consequently, takeoff and landing distances increase.
2. Ride Quality and Turbulence
Aircraft with high wing loading (like commercial jets) tend to cut through turbulence better than aircraft with low wing loading (like gliders). A low wing loading plane is easily tossed around by gusts of wind because it has a large surface area relative to its weight.
3. Maneuverability
Low wing loading allows for tighter turning radii and slower flight capabilities, which is why gliders and aerobatic planes often aim for lower ratios. However, high wing loading is necessary for high-speed cruise efficiency.
Wing Loading Examples
Aircraft Type
Typical Wing Loading
Characteristics
Gliders
6 – 7 lbs/ft²
Extremely efficient, slow landing speeds, sensitive to thermals.
Requires long runways, very stable at high speeds.
Wing Loading in RC Planes
For Radio Control (RC) hobbyists, wing loading is the primary metric used to determine how difficult a model will be to fly. A "Cube Loading" (WCL) factor is also sometimes used for scaling comparisons, but standard wing loading (oz/ft²) remains the industry standard.
Under 10 oz/ft²: Indoor flyers, park flyers, and gliders. Very easy to fly.
15 – 20 oz/ft²: Sport planes and trainers. Good wind penetration.
Over 30 oz/ft²: Large warbirds and jets. These "fly heavy" and require experienced pilots to manage energy during landing.