THE LAST FEW METRES CHANGE THE FLOW.
Set a flare event and compare the same approach with and without the ground. Follow height, speed and lift together.
Drag to orbit · right-drag to pan · scroll to zoom. Body pitch = path angle + incidence. Height is exaggerated ×10 relative to distance. A is amber; B is turquoise.
A fair ground-effect comparison keeps mass, speed, height and control inputs identical.
Whole-run summary · live values appear above
CAUSE → RESPONSE → COMPARISON
B · solid turquoise A · dashed amber
Time plots share the playback cursor. Design sweeps and phase plots retain their own axes. A stopped run holds its final resolved state.
| Whole-run quantity | A · saved | B · live | B − A | Unit |
|---|
A snapshot includes parameter values and event times. Export retains both configurations and their calculated traces.
THE PHYSICS BEHIND THE RESPONSE
Follow each balance, then connect it to the response above. Open Symbols & units for the notation. A dot denotes a time derivative unless a non-dimensional time is stated.
The flare changes lift and path curvature; weight still acts vertically. Contact occurs when wheel height reaches zero.
This smooth teaching fit reduces induced drag as the wing approaches the surface. With ground effect switched off, φ is set to 1.
The same ground factor changes both the lift slope and the induced-drag term. The profile-drag coefficient remains 0.04.
The selected incidence step is followed with a finite response time. This is a prescribed-incidence point-mass model, not a solved pitch-control or landing-gear model.
Equations describe this bounded teaching model. Assumptions and source references are retained below. Internal calculations use SI units; controls and plots show their own labelled units.
Generic point mass; S = 24 m², span 13 m, e = 0.8, sea-level density 1.225 kg/m³. Wing is 2 m above wheel contact height. The smooth ground-effect factor is an illustrative fit to the FAA approximate induced-drag reductions at h/b = 0.1 and 0.25; it is not a CFD solution or a particular wing measurement. Initial path −3°. Incidence follows a first-order command; body pitch dynamics are excluded. Integration stops at touchdown, CL > 1.6, TAS < 25 m/s, |γ| > 20°, or 60 s. No tyre, strut, crosswind or autopilot flare model.
FAA · Ground effect ↗Numerical checks test the stated equations. They do not establish aircraft certification or experimental accuracy. Schematic flow markers indicate direction; their speed is illustrative. No manufacturer geometry or performance data is reproduced. Version: coupled-labs-v1.1.