| Club | Ball speed | Launch | Backspin | Carry | Apex |
|---|
A golf ball in flight is pushed by three forces: gravity, drag (opposing its motion through the air), and Magnus lift (the sideways/upward force from spin, the same effect that curves a soccer free kick or a spinning baseball). This simulator integrates all three numerically in 3D — downrange, height, and left/right curve — using RK4, the same verified integration method used elsewhere on this site. Backspin creates lift (holding the ball up and extending carry); tilt that spin axis off-vertical and the same effect pulls the ball sideways into a draw or fade.
A PGA Tour average driver swing — 167 mph ball speed, 10.9° launch, 2,545 rpm backspin — carries roughly 260–265 yards in this model with no wind at sea level, matching published Tour averages closely. Tilt the spin axis 20° and the same swing curves about 35–40 yards offline by landing — a real slice or hook, not a cosmetic bend.
Magnus lift fights gravity for longer, flattening the descent and extending the time the ball spends moving forward before it falls — up to a point. Too much spin (a "sky ball") adds height without adding distance, since the extra lift steepens the whole trajectory instead of extending it.
Grass gets trapped between the clubface and the ball at impact — the "flyer lie" — reducing the friction that normally imparts spin. Less backspin means less lift and a lower, longer-rolling, less controllable shot, which is exactly why rough is harder to stop on the green from.
Thinner air means less drag and less Magnus lift working on the ball — the classic "ball flies farther in Denver" effect. It also means slightly less lift, so very high-spin, high-altitude shots can fly a little flatter than expected even as they go farther overall.
Roll depends heavily on turf firmness, which this model doesn't simulate — the total-distance readout uses a simple descent-angle-based estimate (steeper landing angle, less roll) and should be read as illustrative, not exact.