Wing area and stall speed | AeroModel Projects

Aim and method

I wanted to see how a larger wing would affect the minimum speed needed to keep the same aircraft in level flight. After looking at the calculator, I expected stall speed to fall, but not in direct proportion to the increase in area.

I started with the Light aircraft preset and changed wing area from 16.2 m² to 20.25 m², then 24.3 m²: increases of 25% and 50%. I kept all other inputs unchanged and recorded the estimated stall speed for each area.

Mass stayed at 1,110 kg, altitude at 1,500 m and maximum lift coefficient at 1.6. The calculator estimated air density as 1.058 kg/m³.

The remaining preset inputs were 62 m/s airspeed, CL = 0.55, CD = 0.032 and 3,100 N thrust. These are assumed example values, not measurements from a specific aircraft.

Results

Estimated stall speed for each wing area
Wing area	Stall speed	Reduction
16.2 m²	28.2 m/s	Baseline
20.25 m²	25.2 m/s	10.6%
24.3 m²	23.0 m/s	18.4%

The 25% larger wing reduced estimated stall speed by 10.6%; the 50% larger wing reduced it by 18.4%. My prediction was right: more wing area helped, but the speed reduction was smaller than the area increase.

Calculator scenarios: Original wing · +25% area · +50% area

Calculation

The lift equation is L = ½ρV²SC_L. To estimate stall speed in level flight, I set maximum available lift equal to the aircraft's weight (mg). Rearranging gives:

V_{s} = \sqrt{\frac{2 m g}{ρ S C_{L, \max}}}

Here ρ is air density, S is wing area, m is mass and g is gravity. Using the 20.25 m² wing:

V_s = √[(2 × 1110 × 9.80665) / (1.058 × 20.25 × 1.6)] ≈ 25.2 m/s

With the other terms fixed, stall speed varies as 1/√S. For 50% more area, 1/√1.5 ≈ 0.816: about 18.4% below the original speed. The square root explains why the reduction is not 50%.

What I learned

I initially described the upward force as thrust, but it is lift. I also understood the difference between CL = 0.55, used for the displayed lift at 62 m/s, and CL max = 1.6, used for the stall estimate. The calculator does not automatically adjust these inputs to balance lift and weight.

My first concern with a larger wing was extra weight and reinforcement. Lower stall speed is useful, but it does not make the biggest wing the best choice. I also learned that a wing bending does not automatically mean it is weak.

Limitations

This was a calculator comparison, not a physical flight test. A real wing redesign could change mass, drag, stability and maximum lift coefficient; I held those factors fixed to isolate wing area.

Calculator screenshots

I took these screenshots during the two larger-area runs. They show calculated results, not flight measurements.

Calculator screenshot with wing area 20.25 square metres and estimated stall speed 25.2 metres per second — Figure 1. Wing area 20.25 m²; estimated stall speed 25.2 m/s.

Calculator screenshot with wing area 24.3 square metres and estimated stall speed 23 metres per second — Figure 2. Wing area 24.3 m²; estimated stall speed 23.0 m/s.