Drela SuperGee II — a 1.5 m discus-launch glider, drawn to the planvsSurf / pump foil — 900 mm reference front wing
root section ag455ct02r → a18 · tip section ag47ct02r → — · sweep parameter 3.400 → 8.553 · dihedral 4.00° → -1.50° · area 218576 mm² → 111865 mm² · span 1498 mm → 900 mm
units
These analyses are not directly comparable
- different fluids (air vs water-salt) — density and viscosity both differ, so the drag numbers are not on the same footing
- different trim loads (2 N vs 932 N) — each wing is carrying a different weight
The geometry comparison below is unaffected — it is a comparison of shapes, not of runs.
- Drela SuperGee II — a 1.5 m discus-launch glider, drawn to the plan
- Surf / pump foil — 900 mm reference front wing
What changed
| Property | Drela SuperGee II | Surf / pump foil | Change | % |
|---|---|---|---|---|
| Geometry | ||||
| Span | 1498 mm | 900 mm | -598 mm | -39.9% |
| Root chord | 183 mm | 150 mm | -33 mm | -18.0% |
| Tip chord | 94 mm | 76 mm | -18 mm | -19.1% |
| Sweep parameter | 3.400 | 8.553 | +5.153 | +151.6% |
| Dihedral | 4.00° | -1.50° | -5.50° | -137.5% |
| Tip twist | 0.00° | -2.00° | -2.00° | — |
| TE thickness | 0 mm | 0 mm | -0 mm | -16.7% |
| Tip cap peak (chord fraction) | 0.500 | 0.450 | -0.050 | -10.0% |
| Tip cap reach | 0.400 | 0.350 | -0.050 | -12.5% |
| Derived | ||||
| Aspect ratio | 10.266 | 7.241 | -3.026 | -29.5% |
| Area | 218576 mm² | 111865 mm² | -106711 mm² | -48.8% |
| Taper | 0.514 | 0.507 | -0.007 | -1.4% |
| MAC | 151 mm | 128 mm | -23 mm | -15.3% |
| Sections | ||||
| Root section | ag455ct02r | a18 | changed | — |
| Tip section | ag47ct02r | — | changed | — |
| Shapedeviation at matched span fractions, 64 samples | ||||
| Chord deviation (max) | 33 mm | |||
| Chord deviation (RMS) | 23 mm | |||
| Twist deviation (max) | 2.00° | |||
| Dihedral deviation (max) | 64 mm | |||
| Tip cap deviation (max) | 306 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 — “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×); “Surf / pump foil” integrates to CL 0.022 against the polar’s CL at the same α (this analysis predates the loading reporting its own) 0.363 (0.06×). A loading that does not integrate back to its own wing’s CL is not a coarse curve, it is a wrong one.
mixed fluids (air, water (sea))
data
| V (kt) | Drela SuperGee II | Surf / pump foil |
|---|---|---|
| 8.75 | 13.28 | 19.18 |
| 9.60 | 16.67 | 22.03 |
| 10.45 | 18.11 | 24.17 |
| 11.30 | 18.91 | 25.35 |
| 12.15 | 19.30 | 25.81 |
| 13.00 | 19.35 | 25.87 |
| 13.85 | 19.11 | 25.57 |
| 14.70 | 18.62 | 24.96 |
| 15.55 | 17.97 | 24.15 |