What if a plane had different wings?

Planes have long wings. Birds have wings too.

What if a plane had little short wings? Could it still fly?

Every plane needs wings big enough to hold it up. In our model, a small four-seat plane has wings with a total area of about 16 square meters, measured from above, and the model's airliner has wings more than seven times as big.

So what if we gave the small plane wings with only half that area, keeping its weight, speed and wing tilt the same? Would it still stay up? And if not, what could the pilot do about it?

Wing area is one of the main design choices for any aircraft. It sets how much lift the wing can make at a given speed, and so how fast the plane must go to stay airborne.

This lab takes a 1,100 kg plane at sea level, flying at 60 m/s with its wing tilted 5° into the airflow, and halves its wing area from 16.2 m² to 8 m². The question: does lift still match weight, and if not, what speed would restore it?

Our plane has normal wings. It flies fast through the air.

The wings push air down. The air pushes the wings up. Up goes the plane!

As the plane moves, its tilted wings turn the air flowing past them downward, and the air pushes back up on the wings. That upward push is lift.

In the model, the plane weighs about 1,100 kilograms. With its normal 16-square-meter wings at 60 meters per second, the lift is about one and a half times its weight: plenty to fly. The model says it would need at least about 50 meters per second at this wing tilt.

With S = 16.2 m², v = 60 m/s, α = 5° and sea-level air (1.225 kg/m³), the model's lift coefficient is 0.43 and the lift 15.5 kN against a weight of 10.8 kN: 143%. The minimum speed at this tilt is 50.1 m/s, and the lowest possible speed, at the 15° stall angle, is 28.9 m/s.

The model only compares lift with weight: lift above 100% means the wing can hold the plane up with some to spare, and a smaller tilt would bring the two level.

Now Olly makes the wings much smaller. There is less wing to push the air.

Now the push is too weak. The plane can't stay up, unless it goes much faster!

Choose the short wings, with about half the area. Everything else stays the same. The lift drops to about seven tenths of the plane's weight: not enough. In the model, the plane can't fly.

There are two ways to fix it. Fly faster: the model says the plane now needs about 71 meters per second instead of 50. Or tilt the wings up more: at 10 degrees, the small wings give enough lift at 60 meters per second. But in the model, tilt them past 15 degrees and the wing stalls.

With S = 8 m² the lift falls to 7.64 kN, 71% of the weight, and the plane cannot fly. Lift scales with v², so the speed needed scales with 1/√S: 50.1 × √(16.2/8) = 71.3 m/s. The stall speed rises the same way, from 28.9 to 41.2 m/s.

Alternatively the tilt can rise: at 10° the coefficient doubles to 0.87 and lift returns to 141% of weight. Above 15° the model's wing stalls and lift falls, so tilt cannot make up for an arbitrarily small wing.

A big wing pushes lots of air down. A small wing pushes less air down.

Less air pushed down means less push up. Going faster helps, because more air rushes past.

Lift depends on four main things: how fast the air flows past, how big the wing is, how thick the air is and how the wing is tilted. A wing half the size turns half as much air downward, so it makes half the lift.

Speed matters even more, because lift grows with the square of speed. Fly twice as fast and you get four times the lift. That's why a plane with small wings has to go much faster. Our model leaves out flaps, drag and engines, and uses a simple wing shape.

In L = ½ρv²SC_L, S enters linearly and v quadratically, so halving S at fixed v, ρ and α halves L, while recovering it needs v × √2. The model's C_L = 2πα/(1 + 2/AR) is thin-airfoil theory with a finite-wing correction; the aspect ratio stays 7.5 here, so the smaller wing is a scaled-down copy.

Limits: a symmetric wing section, a fixed 15° stall with a rough post-stall drop, no flaps or slats, no fuselage or tail lift, and no drag or thrust. It compares lift with weight only; whether the engine could reach 71 m/s is outside the model.

Real planes go slowly when they take off and land.

So they slide out extra parts on their wings. The wings get bigger, and the plane gets more lift.

NASA explains that a wing's lift depends on its shape, its area and the plane's speed. Planes fly fairly slowly when they take off and land, so designers add moving parts to the wings: slats at the front and flaps at the back.

Sliding the flaps back and the slats forward makes the wing area bigger, and tipping them down changes the wing's shape. Both give more lift at low speed. Next time you fly, watch the wings during takeoff and landing.

NASA's lift equation states that lift depends on air density, the square of velocity, the wing area, the body's shape and its inclination to the flow. Its page on flaps and slats explains that because takeoff and landing are slow, designers increase wing area by moving flaps aft and slats forward along tracks, and increase effective camber by pivoting them down. Flaps also add drag, which helps slow the plane for landing.

So real aircraft that need lift at low speed, as this lab's small wing does, enlarge and reshape their wings for takeoff and landing. NASA adds that after touchdown, spoilers on top of the wing cut the lift and add drag.