This is an earlier experiment. Read the amendments below before treating its findings as current.
The question
In 5 m/s wind, gentle-crosswind lanes sat 100–185 m off, more than simple arithmetic predicted.
What was tested
We switched gusts off, halved and doubled the pull strength (return speed asked per metre off-lane), switched speed-matching off, gave ideal craft (they respond instantly) the wing's slow response, and flew half-hour runs (twelve layouts).
What was found then
Offsets stayed large without gusts. They follow a simple balance: the 80 m either side of centre where no pull acts, plus crosswind speed divided by pull strength, about 97 m for ideal craft. On a traced layout, speed-matching only delayed reaching that point, by 5–10 minutes. The wing sits about 45 m farther out, like an ideal craft given the wing's slow response. Strong-crosswind lanes kept drifting all half hour, ending 3.4–3.8 km off; a stronger pull limit let ideal craft hold them, at a safety cost.
What we learned later
'Not gusts' was narrowed: offsets stay with gusts off, but how much gusts add is unknown.
research/reviews/brief-c57.md
'Does not move the resting point' was narrowed to 'ends within 3 m on this layout'; smaller shifts are unknown.
research/reviews/brief-c60.md
What changed
Nothing. A pull-strength setting was added; default unchanged.
Corrections retained in the record
Earlier wording: still creeping toward their lanes at a few centimetres per second
Record correction: median per-craft slopes 0.03–0.18 m/s
research/reviews/brief-c58.md
Numbers and source references
- ×0.5 / ×2
- gain settingsresearch/reviews/brief-c57.md
- 12
- seeds per settingresearch/reviews/brief-c57.md
- 97 m
- 80 + 1.7 m/s ÷ gain 0.1, idealised resting offsetresearch/reviews/brief-c56.md
- 97–98 m
- reference offset on gentle lanes from minute 10–15, rule onresearch/reviews/brief-c59.md
- 600–900 s
- time by which the rule-on fleet reached the balanceresearch/reviews/brief-c59.md
- 3 m
- rule on vs off at 30 minresearch/reviews/brief-c59.md
- 142 / 145 m
- wing / slow-response reference without velocity matchingresearch/reviews/brief-c58.md
- ~2 m/s; 3.4–3.8 km
- strong-crosswind drift speed; offset at 30 minresearch/reviews/brief-c59.md
- 1.2–1.3 km → 300–650 m
- reference craft, strong lanes, cap raised to 1.0research/reviews/brief-c56.md