Schempp-Hirth Standard Cirrus — 15 m, two Wortmann sectionsvsPiper PA-28 Cherokee — the Hershey-bar wing
root section fxs02196 → naca652415 · tip section fx6617a2 → — · tip chord 345 mm → 1626 mm · dihedral 2.00° → 7.00° · taper 0.404 → 1.000 · mac 705 mm → 1626 mm
units
These analyses are not directly comparable
- different trim loads (3237 N vs 9565 N) — each wing is carrying a different weight
The geometry comparison below is unaffected — it is a comparison of shapes, not of runs.
- Schempp-Hirth Standard Cirrus — 15 m, two Wortmann sections
- Piper PA-28 Cherokee — the Hershey-bar wing
What changed
| Property | Schempp-Hirth Standar… | Piper PA-28 Cherokee | Change | % |
|---|---|---|---|---|
| Geometry | ||||
| Span | 15000 mm | 9144 mm | -5856 mm | -39.0% |
| Root chord | 855 mm | 1626 mm | +771 mm | +90.2% |
| Tip chord | 345 mm | 1626 mm | +1281 mm | +371.3% |
| Sweep parameter | 2.946 | 0.000 | -2.946 | -100.0% |
| Dihedral | 2.00° | 7.00° | +5.00° | +250.0% |
| Tip twist | -2.00° | 0.00° | +2.00° | -100.0% |
| TE thickness | 2 mm | 3 mm | +1 mm | +50.0% |
| Tip cap reach | 0.450 | 0.300 | -0.150 | -33.3% |
| Derived | ||||
| Aspect ratio | 22.496 | 5.624 | -16.872 | -75.0% |
| Area | 10001997 mm² | 14868144 mm² | +4866147 mm² | +48.7% |
| Taper | 0.404 | 1.000 | +0.596 | +147.8% |
| MAC | 705 mm | 1626 mm | +921 mm | +130.7% |
| Sections | ||||
| Root section | fxs02196 | naca652415 | changed | — |
| Tip section | fx6617a2 | — | changed | — |
| Shapedeviation at matched span fractions, 64 samples | ||||
| Chord deviation (max) | 1281 mm | |||
| Chord deviation (RMS) | 974 mm | |||
| Twist deviation (max) | 2.00° | |||
| Dihedral deviation (max) | 299 mm | |||
| Tip cap deviation (max) | 3101 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 — “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×); “Piper PA-28 Cherokee” integrates to CL 0.007 against the polar’s CL at the same α (this analysis predates the loading reporting its own) 0.271 (0.03×). 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) | Schempp-Hirth Standar… | Piper PA-28 Cherokee |
|---|---|---|
| 59.40 | 43.23 | 11.06 |
| 60.75 | 43.27 | 11.54 |
| 65.00 | 42.76 | 13.05 |
| 68.12 | 42.07 | 14.15 |
| 69.25 | 41.82 | 14.68 |
| 73.50 | 40.61 | 16.66 |
| 76.85 | 39.49 | 18.21 |
| 77.75 | 39.18 | 18.56 |