01 / READ THE CHANGE
Wheel speed is a state
Brake torque slows the wheel; tyre force slows the aircraft and spins the wheel forwards. They are coupled through slip.
FOLLOW THE ENERGY TO THE RUNWAY.
Wheel Braking, Anti-skid & Brake Energy
Watch wheel speed separate from ground speed. Compare locked-wheel braking with a pressure-dumping anti-skid controller.
INTERACTIVE CALCULATED DIAGRAMB · LIVE
Diagram · drag background to pan
Drag the turquoise handles, or focus a handle and use arrow keys. The sliders provide the same controls.
Preparing the calculation…
A · no saved reference
02 / READ THE CHANGE
Release to recover
The illustrative anti-skid controller dumps pressure above 0.16 slip and reapplies below 0.08. Its actuator has a finite response time.
03 / READ THE CHANGE
Account for all the energy
Kinetic energy becomes brake heat, tyre slip heat and aerodynamic work. Brake heat alone is not the full aircraft energy loss.
THE SAME MODEL, CONNECTED VIEWS
Follow the calculation
B · solid turquoise A · dashed amber
Compare A and B
| Quantity | A · saved | B · live | B − A | Unit |
|---|
A remains fixed until saved again. Export includes the model version, settings and plotted data.
Equations, assumptions & sources
Read the balance, then connect each symbol to the model. Open a symbol key for definitions and units. Long equations can be scrolled sideways.
01 · Aircraft deceleration and wheel rotation
These balances describe one of four equal wheel–mass shares in the model.
Symbols & units
- Quarter of aircraft mass, kg; wheel inertia, kg m²; wheel radius, m.
- Tyre force and allocated drag, N; effective brake torque, N m.
02 · Slip measures wheel-speed mismatch
The physical ratio applies for V > 0. Near rest the code divides by max(V, 0.3 m/s) and bounds the result between 0 and 1.
Symbols & units
- Ground speed, m/s; wheel angular speed, rad/s.
- Dimensionless. Zero means free rolling; one indicates a locked wheel while moving.
03 · Where the kinetic energy goes
Brake-disc heating and tyre-slip heating are separate energy paths.
Symbols & units
- Thermal power, W; an energy rate, not accumulated heat.
- Effective wheel brake torque. The code handles the stationary-wheel torque balance explicitly.
Four equally loaded wheels, radius 0.5 m, inertia 20 kg m² each, brake thermal capacity 100 kJ/K. Synthetic μ(s)=μscale(1−exp(−s/0.04))exp(−1.4s), actuator lag 0.08 s, maximum torque 16 kN m. No reverse thrust, load transfer, lift unloading, thermal fade or certified runway prediction. The chart ends at the last resolved low-speed sample.
FAA · aviation handbook library ↗Physical relations and teaching sources support the stated concepts. Generic coefficients are explicitly illustrative; they are not measured manufacturer data. Numerical verification is separate from experimental validation. Model version: applied-labs-v1.1.