This is an earlier experiment. Read the amendments below before treating its findings as current.

The question

What wind stops the lane flying into it from making progress, for wings and ideal craft (they respond instantly)?

What was tested

We counted laps per lane in half-hour runs, winds 0.63 to 1.0 of cruise speed, steady and gusty; then close calls minute by minute on 144 re-flown runs.

What was found then

In steady wind, ideal craft's into-wind lane delivers 36 % of calm at 0.63 of cruise, 0.6 % at 1.0; other lanes keep delivering. It falls below 10 % at about 0.89 of cruise for ideal craft and 0.86–0.87 for the wing, gusty or steady. Near that limit the wing makes 23–25 % less headway and loses 6–10 more craft per run. Gusts add about 1.7 % more of the run in close calls for the wing, and the closest pair each minute involved more different craft (about 230).

What we learned later

LATER / CYCLE 67

'Gusts neither cost nor buy safety' (cycle 66) was taken back: the close-call-time count shows a gust cost for the wing.

research/reviews/brief-c68.md

LATER / CYCLE 68

'Gusts change none of the limit' was narrowed: no gust difference in headway was found, but sameness was not shown.

research/reviews/brief-c69.md

LATER / CYCLE 69

The ~230-craft reading was disputed: counts of the closest pair cannot show how the extra close-call time is spread across craft.

research/reviews/auditor-c69.md

What changed

Nothing.

Corrections retained in the record

  • Earlier wording: the wing is within 6 to 15 percent of that at every wind

    Record correction: 6–15 % at 0.63 and 0.88; at 1.0 the wing delivered 1.29× the reference (both near zero)

    research/reviews/brief-c66.md

  • Earlier wording: the last 0.3 m/s of headway is not delivered

    Record correction: 0.3 is the predicted laps per craft-hour at wind 8; the registered formula gives about 0.14 m/s (envelope.md:2222 repeats the slip)

    research/reviews/brief-c66.md

Numbers and source references
1 800 s
run lengthresearch/reviews/brief-c66.md
72 / 72 / 168 / 144
runs in cycles 65 / 66 / 67 / 68research/reviews/brief-c66.md; research/reviews/brief-c67.md; research/reviews/brief-c68.md; research/reviews/brief-c69.md
16
calm reference laps per craft-hour (kinematic)research/reviews/researcher-c68.md
36 / 11 / 0.6 %
against-wind laps as share of calm, reference craft, steadyresearch/reviews/brief-c66.md
0.89; 0.86–0.87
interpolated 10 % crossing, reference; wingresearch/reviews/brief-c68.md
23–25 %
wing headway shortfall near the floorresearch/reviews/brief-c68.md
6–10
extra wing craft lost per run vs reference (+6.3 to +10)research/reviews/brief-c66.md; research/reviews/brief-c68.md
0.017
extra fraction of run time with a pair too close, wing, gustsresearch/reviews/brief-c68.md
~230
distinct craft in the worst pair, wing, gusty (213–220 → 228)research/reviews/brief-c69.md
Original structured record ↗