RC Wing Loading Calculator
Calculate wing loading for RC aircraft to predict flight characteristics, stall speed, and handling behavior.
What is wing loading?
Wing loading is the ratio of the aircraft’s total weight to its wing area. It is the single most important number for predicting how an RC plane will fly — its speed, stall behavior, maneuverability, and landing characteristics.
Formula:
Wing Loading (oz/sq ft) = All-Up Weight (oz) ÷ Wing Area (sq ft)
Wing Loading (g/dm²) = All-Up Weight (g) ÷ Wing Area (dm²)
Conversion: 1 oz/sq ft = 30.5 g/dm²
Wing loading categories (RC aircraft):
| Wing Loading (oz/sq ft) | Flight Characteristics | Typical Aircraft |
|---|---|---|
| 4–8 | Ultra-slow, floaty, very forgiving | Slow sticks, park flyers |
| 8–14 | Slow, stable, beginner-friendly | Trainers, gliders |
| 14–20 | Moderate speed, good maneuverability | Sport planes, scale warbirds |
| 20–28 | Fast, responsive, intermediate+ | Aerobatic, pattern planes |
| 28–40 | Very fast, snappy rolls, advanced | Scale jets, racing |
| 40+ | Extremely fast, expert only | EDF jets, speed models |
Wing area calculation:
For rectangular wings: Area = Wingspan × Chord
For tapered wings: Area = Wingspan × (Root chord + Tip chord) ÷ 2
For elliptical wings: Area = Wingspan × Chord × π ÷ 4
Stall speed estimation:
Stall speed (mph) ≈ 3.7 × √(Wing Loading in oz/sq ft)
This is a rough approximation for typical RC airfoils at sea level.
Worked example:
A 48" wingspan sport plane:
- Wingspan: 48" = 4 ft
- Chord: 8" = 0.667 ft
- Wing area: 4 × 0.667 = 2.67 sq ft (384 sq in)
- All-up weight: 42 oz
- Wing loading: 42 ÷ 2.67 = 15.7 oz/sq ft
- Estimated stall speed: 3.7 × √15.7 = 14.7 mph
This falls in the “moderate speed” category — a good sport flyer that handles well in light wind.
Wind sensitivity:
Lower wing loading = more affected by wind. A rule of thumb: the minimum comfortable flying wind speed equals the stall speed. If your plane stalls at 8 mph, you will struggle in 15+ mph wind. Higher wing loading planes penetrate wind better.
Design trade-offs:
- Low wing loading: slower, more forgiving, shorter takeoff roll, but poor wind performance
- High wing loading: faster, crisper aerobatics, good in wind, but faster landing speed and higher stall speed
- For beginners, aim for 8–14 oz/sq ft
- For sport/aerobatic, 14–24 oz/sq ft is the sweet spot