Piper J-3 Cub — a rectangular wing that worksvsSchempp-Hirth Standard Cirrus — 15 m, two Wortmann sections
root section usa35b → fxs02196 · tip section — → fx6617a2 · aspect ratio 6.945 → 22.496 · dihedral 1.00° → 2.00° · tip chord 1545 mm → 345 mm · taper 1.000 → 0.404
units
These analyses are not directly comparable
- different trim loads (5396 N vs 3237 N) — each wing is carrying a different weight
The geometry comparison below is unaffected — it is a comparison of shapes, not of runs.
- Piper J-3 Cub — a rectangular wing that works
- Schempp-Hirth Standard Cirrus — 15 m, two Wortmann sections
What changed
| Property | Piper J-3 Cub | Schempp-Hirth Standar… | Change | % |
|---|---|---|---|---|
| Geometry | ||||
| Span | 10730 mm | 15000 mm | +4270 mm | +39.8% |
| Root chord | 1545 mm | 855 mm | -690 mm | -44.7% |
| Tip chord | 1545 mm | 345 mm | -1200 mm | -77.7% |
| Sweep parameter | 0.000 | 2.946 | +2.946 | — |
| Dihedral | 1.00° | 2.00° | +1.00° | +100.0% |
| Tip twist | 0.00° | -2.00° | -2.00° | — |
| TE thickness | 3 mm | 2 mm | -1 mm | -33.3% |
| Tip cap reach | 0.300 | 0.450 | +0.150 | +50.0% |
| Derived | ||||
| Aspect ratio | 6.945 | 22.496 | +15.551 | +223.9% |
| Area | 16577850 mm² | 10001997 mm² | -6575853 mm² | -39.7% |
| Taper | 1.000 | 0.404 | -0.596 | -59.6% |
| MAC | 1545 mm | 705 mm | -840 mm | -54.4% |
| Sections | ||||
| Root section | usa35b | fxs02196 | changed | — |
| Tip section | — | fx6617a2 | changed | — |
| Shapedeviation at matched span fractions, 64 samples | ||||
| Chord deviation (max) | 1200 mm | |||
| Chord deviation (RMS) | 894 mm | |||
| Twist deviation (max) | 2.00° | |||
| Dihedral deviation (max) | 171 mm | |||
| Tip cap deviation (max) | 2333 mm | |||
Performance
CoefficientsDimensionless — how good the shape is, independent of size and speed.
ForcesNewtons and watts — what each wing actually carries and costs at this condition.
Spanwise
withheld — “Piper J-3 Cub” integrates to CL 0.002 against the polar’s CL at the same α (this analysis predates the loading reporting its own) 0.330 (0.01×); “Schempp-Hirth Standar…” integrates to CL 0.052 against the polar’s CL at the same α (this analysis predates the loading reporting its own) 0.541 (0.10×). A loading that does not integrate back to its own wing’s CL is not a coarse curve, it is a wrong one.
air, ρ = 1.225 kg/m³
data
| V (kt) | Piper J-3 Cub | Schempp-Hirth Standar… |
|---|---|---|
| 39.48 | 12.13 | 33.05 |
| 42.28 | 13.83 | 35.72 |
| 43.74 | 14.74 | 37.11 |
| 47.38 | 17.02 | 39.69 |
| 47.99 | 17.39 | 40.12 |
| 52.24 | 19.95 | 42.14 |
| 52.48 | 20.10 | 42.20 |
| 56.49 | 21.81 | 43.13 |
| 57.59 | 22.28 | 43.17 |
| 60.75 | 23.21 | 43.27 |
| 62.69 | 23.78 | 43.04 |
| 65.00 | 24.36 | 42.76 |
| 67.79 | 25.06 | 42.14 |
| 69.25 | 25.30 | 41.82 |
| 72.89 | 25.88 | 40.79 |
| 73.50 | 25.92 | 40.61 |
| 77.75 | 26.23 | 39.18 |