Schempp-Hirth Standard Cirrus — 15 m, two Wortmann sectionsvsDrela SuperGee II — a 1.5 m discus-launch glider, drawn to the plan
root section fxs02196 → ag455ct02r · tip section fx6617a2 → ag47ct02r · dihedral 2.00° → 4.00° · tip twist -2.00° → 0.00° · area 10001997 mm² → 218576 mm² · span 15000 mm → 1498 mm
units
These analyses are not directly comparable
- different trim loads (3237 N vs 2 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
- Drela SuperGee II — a 1.5 m discus-launch glider, drawn to the plan
What changed
| Property | Schempp-Hirth Standar… | Drela SuperGee II | Change | % |
|---|---|---|---|---|
| Geometry | ||||
| Span | 15000 mm | 1498 mm | -13502 mm | -90.0% |
| Root chord | 855 mm | 183 mm | -672 mm | -78.6% |
| Tip chord | 345 mm | 94 mm | -251 mm | -72.8% |
| Sweep parameter | 2.946 | 3.400 | +0.454 | +15.4% |
| Dihedral | 2.00° | 4.00° | +2.00° | +100.0% |
| Tip twist | -2.00° | 0.00° | +2.00° | -100.0% |
| TE thickness | 2 mm | 0 mm | -2 mm | -85.0% |
| Sections | 40 | 30 | -10 | -25.0% |
| Tip cap reach | 0.450 | 0.400 | -0.050 | -11.1% |
| Derived | ||||
| Aspect ratio | 22.496 | 10.266 | -12.229 | -54.4% |
| Area | 10001997 mm² | 218576 mm² | -9783421 mm² | -97.8% |
| Taper | 0.404 | 0.514 | +0.110 | +27.3% |
| MAC | 705 mm | 151 mm | -553 mm | -78.5% |
| Sections | ||||
| Root section | fxs02196 | ag455ct02r | changed | — |
| Tip section | fx6617a2 | ag47ct02r | changed | — |
| Shapedeviation at matched span fractions, 64 samples | ||||
| Chord deviation (max) | 672 mm | |||
| Chord deviation (RMS) | 537 mm | |||
| Twist deviation (max) | 2.00° | |||
| Dihedral deviation (max) | 210 mm | |||
| Tip cap deviation (max) | 6820 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×); “Drela SuperGee II” integrates to CL 0.056 against the polar’s CL at the same α (this analysis predates the loading reporting its own) 0.371 (0.15×). 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… | Drela SuperGee II |
|---|---|---|
| 0.014 | 0.622 | 0.259 |
| 0.014 | 0.625 | 0.261 |
| 0.016 | 0.666 | 0.290 |
| 0.017 | 0.722 | 0.327 |
| 0.017 | 0.731 | 0.332 |
| 0.019 | 0.789 | 0.371 |
| 0.022 | 0.867 | 0.417 |
| 0.022 | 0.878 | 0.425 |
| 0.026 | 0.985 | 0.491 |
| 0.028 | 1.04 | 0.522 |
| 0.032 | 1.12 | 0.574 |
| 0.039 | 1.28 | 0.656 |