Contents

Documentation

The models behind every number in PaceDynamics: what each one computes, what it assumes, and a script to check it yourself.

Every page opens with a drawing and states its model as equations, with the assumptions that go with them. Figures that show numbers were drawn by the app from the Formula Student single-car template, the template you can open in the app. Each page ships a GNU Octave script that writes the model the way a textbook would and compares it with the app's own numbers for that car; the same scripts run in MATLAB. Replace the example car with yours to check the app on your own car.

Foundations

Axes, signs and units: Which way is positive for every number the app shows, and the units it shows them in.
Sprung and unsprung mass: The body on its springs and the wheels under them, and what the two masses do to the ride.

Suspension

Wishbones and struts: How the links carry a wheel through its travel, and what that does to its camber, its toe and the spring it works.
Roll and pitch centres: Where the links take a tyre's force into the body, and how much of the load transfer skips the springs.
Anti-dive and anti-squat: How much of the car's pitch under braking and drive the links hold up, instead of the springs.
Steering axis and Ackermann: The line a front wheel steers about, where it meets the road, and how far each wheel turns for the rack.
Kinematics and compliance: What a K&C rig measures: the springs as the wheel sees them, where it stops, and how far the links give under the tyre's forces.
Forces in the links: What each link of a corner carries when the tyre pushes on it, and the most it has to carry.

Springs and dampers

Springs, bars, heave and roll elements: What each spring gives the wheel, and in which motion: corner springs, anti-roll bars, and the heave and roll elements of a decoupled car.
Ride and roll rates: How stiff the car is in heave, roll and pitch, from the springs, the bars and the tyres under them.
Dampers: A damper's force against its speed, what it gives the wheel, the one number a linear model takes from it, and how damped that leaves the body's heave, pitch and roll.
Ride over a rough road: The whole car driven over a road of stated roughness: an ISO 8608 surface, seven degrees of freedom, the rear wheels a wheelbase behind, and how far each tyre's load swings.

Loads

Load transfer: How cornering and braking move the car's weight between its wheels, and which parts of the car decide where it goes.

Tyres

Slip and the Magic Formula: How a tyre makes force by slipping, and the formula the app reads a tyre's force from.
Combined slip: What a tyre can do when it corners and drives or brakes at once, and how the app weighs one force against the other.
Load sensitivity: Why a tyre grips less per newton the harder it is pressed, and why that makes load transfer cost a pair of tyres grip.
Relaxation length: A tyre builds its side force over a distance rolled, not a time, and what that lag does to a car steered quickly.
Fitting tyre data: How the app turns a rig's measured points into a Magic Formula tyre, how close that gets, and how a rig tyre is scaled to the road.

More pages follow, part by part: the rest of the suspension, the tyres, the powertrain and brakes, handling and the lap.