Control a 2D aircraft using pitch (↑↓ keys or buttons). Set thrust and
wing area to explore how angle of attack, airspeed, altitude, and lift
interact. Exceed the critical AoA and the aircraft stalls!
Physics:
L = ½·ρ·C_L(α)·A·v²
D = ½·ρ·C_D(α)·A·v²
C_L(α) ≈ 2π·α (linear)
Stall at α > 15°
Aerodynamic Stall
An aircraft generates lift because the wing's angle of attack (AoA)
deflects air downwards. As AoA increases, lift coefficient C_L
increases linearly — up to the critical angle (~15°).
Beyond it, airflow separates from the upper wing surface, lift drops
sharply, and drag spikes. This is called a stall.
Stall speed depends on aircraft mass, wing area, and air density.
Recovery requires reducing AoA (nose down) and regaining airspeed.
Stalls at low altitude are dangerous because there may not be enough
height to recover.
About Flight Simulator
Aerodynamic flight depends on four forces acting on an aircraft: lift (upward force from wings), weight (gravity pulling down), thrust (forward force from engines), and drag (air resistance opposing motion). Lift is generated by the pressure difference between the curved upper surface and flatter lower surface of a wing—described by Bernoulli's principle and more precisely by the Kutta-Joukowski theorem—and scales with air density, airspeed squared, wing area, and the lift coefficient, which depends on angle of attack.
The angle of attack (AoA) is the angle between the wing chord line and the incoming airflow. Increasing AoA raises the lift coefficient and produces more lift, up to the critical angle (~15–20° for most wings) beyond which airflow separates from the upper surface, causing a sudden drop in lift called a stall. Drag has two components: parasitic drag (increasing with speed squared) and induced drag (decreasing with speed), giving a total drag curve with a minimum at the optimal lift-to-drag ratio airspeed.
This simulator models the aircraft's equations of motion under all four forces, letting you control throttle, elevator (pitch), and see how altitude, airspeed, and rate of climb respond. You can explore the stall boundary, glide ratio, and how reducing drag or increasing thrust changes the aircraft's climb performance—concepts fundamental to pilot training, aircraft design, and understanding why heavier aircraft need longer runways.
Frequently Asked Questions
How does a wing generate lift?
A wing generates lift primarily because its shape and angle of attack deflect airflow downward, and by Newton's third law the wing receives an equal and opposite upward force. Bernoulli's principle explains the associated pressure difference: airflow accelerates over the curved upper surface, reducing pressure, while slower airflow under the wing maintains higher pressure. Both the momentum (circulation) and pressure perspectives are valid and equivalent descriptions of the same aerodynamic phenomenon.
What causes an aircraft to stall?
A stall occurs when the angle of attack exceeds the critical angle (typically 15–20°), causing the boundary layer of air to separate from the upper wing surface. The smooth, attached flow that produces lift breaks down into turbulent, separated flow, and the lift coefficient drops sharply while drag increases. Stalls can occur at any airspeed—what matters is AoA, not speed. Recovery requires reducing AoA by pushing the nose down, allowing flow to reattach.
What is the difference between indicated and true airspeed?
Indicated airspeed (IAS) is what the pitot-static system measures: the dynamic pressure of air relative to the aircraft. True airspeed (TAS) is the actual speed of the aircraft through the air mass, accounting for the lower air density at altitude. At sea level they are approximately equal; at 35,000 ft with ~25% of sea-level density, TAS is about twice IAS. Aircraft stall at a constant IAS regardless of altitude because lift depends on dynamic pressure, not TAS.
How does thrust-to-weight ratio affect performance?
Thrust-to-weight ratio (T/W) determines whether an aircraft can accelerate, maintain level flight, or climb. At T/W = 1, an aircraft can hover vertically (like a rocket). Commercial jets at takeoff have T/W ≈ 0.3, needing speed for aerodynamic lift. Fighter jets with T/W > 1 can accelerate while climbing vertically. Higher T/W reduces takeoff distance, increases rate of climb, and raises service ceiling. Reducing aircraft weight (fuel burn, payload shedding) improves performance in the same way as adding thrust.
What is the glide ratio and why does it matter?
Glide ratio is the horizontal distance an unpowered aircraft travels for each unit of altitude lost—equal to the lift-to-drag ratio (L/D) at the optimum glide speed. A typical commercial airliner has L/D ≈ 17:1 (travels 17 km horizontally for each 1 km of altitude). A modern glider achieves L/D > 50:1. Pilots use glide ratio to determine whether they can reach an airfield after engine failure. At 35,000 ft (≈10.7 km altitude), a jet with L/D = 17 can glide about 180 km without power.