Schempp-Hirth Standard Cirrus — 15 m, two Wortmann sectionsvsGossamer Albatross II — same span, two-thirds the area
root section fxs02196 → l7769 · tip section fx6617a2 → — · area 10001997 mm² → 45296522 mm² · tip chord 345 mm → 1404 mm · sweep parameter 2.946 → 7.476 · mac 705 mm → 1552 mm
units
These analyses are not directly comparable
- different trim loads (3237 N vs 991 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
- Gossamer Albatross II — same span, two-thirds the area
What changed
| Property | Schempp-Hirth Standar… | Gossamer Albatross II | Change | % |
|---|---|---|---|---|
| Geometry | ||||
| Span | 15000 mm | 29260 mm | +14260 mm | +95.1% |
| Root chord | 855 mm | 1651 mm | +796 mm | +93.1% |
| Tip chord | 345 mm | 1404 mm | +1059 mm | +307.0% |
| Sweep parameter | 2.946 | 7.476 | +4.530 | +153.8% |
| Dihedral | 2.00° | 3.60° | +1.60° | +80.0% |
| Tip twist | -2.00° | 0.00° | +2.00° | -100.0% |
| TE thickness | 2 mm | 2 mm | -1 mm | -25.0% |
| Tip cap reach | 0.450 | 0.200 | -0.250 | -55.6% |
| Derived | ||||
| Aspect ratio | 22.496 | 18.901 | -3.595 | -16.0% |
| Area | 10001997 mm² | 45296522 mm² | +35294525 mm² | +352.9% |
| Taper | 0.404 | 0.850 | +0.447 | +110.7% |
| MAC | 705 mm | 1552 mm | +847 mm | +120.2% |
| Sections | ||||
| Root section | fxs02196 | l7769 | changed | — |
| Tip section | fx6617a2 | — | changed | — |
| Shapedeviation at matched span fractions, 64 samples | ||||
| Chord deviation (max) | 1059 mm | |||
| Chord deviation (RMS) | 886 mm | |||
| Twist deviation (max) | 2.00° | |||
| Dihedral deviation (max) | 659 mm | |||
| Tip cap deviation (max) | 7622 mm | |||
Performance
CoefficientsDimensionless — how good the shape is, independent of size and speed.
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×); “Gossamer Albatross II” integrates to CL 0.118 against the polar’s CL at the same α (this analysis predates the loading reporting its own) 0.613 (0.19×). 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
| CD | Schempp-Hirth Standar… | Gossamer Albatross II |
|---|---|---|
| 0.012 | 0.514 | 0.374 |
| 0.012 | 0.541 | 0.418 |
| 0.013 | 0.541 | 0.419 |
| 0.013 | 0.574 | 0.472 |
| 0.014 | 0.625 | 0.535 |
| 0.015 | 0.626 | 0.535 |
| 0.017 | 0.703 | 0.613 |
| 0.017 | 0.731 | 0.635 |
| 0.020 | 0.814 | 0.709 |
| 0.022 | 0.867 | 0.748 |
| 0.025 | 0.958 | 0.829 |
| 0.028 | 1.04 | 0.896 |
| 0.032 | 1.13 | 0.982 |
| 0.039 | 1.28 | 1.11 |