Drela SuperGee II — a 1.5 m discus-launch glider, drawn to the planvsDownwind glide foil — high aspect reference front wing
root section ag455ct02r → e818 · tip section ag47ct02r → — · sweep parameter 3.400 → 9.717 · dihedral 4.00° → -2.50° · tip chord 94 mm → 48 mm · area 218576 mm² → 121109 mm²
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
- Downwind glide foil — high aspect reference front wing
What changed
| Property | Drela SuperGee II | Downwind glide foil | Change | % |
|---|---|---|---|---|
| Geometry | ||||
| Span | 1498 mm | 1240 mm | -258 mm | -17.2% |
| Root chord | 183 mm | 130 mm | -53 mm | -29.0% |
| Tip chord | 94 mm | 48 mm | -46 mm | -48.9% |
| Sweep parameter | 3.400 | 9.717 | +6.317 | +185.8% |
| Dihedral | 4.00° | -2.50° | -6.50° | -162.5% |
| Tip twist | 0.00° | -2.50° | -2.50° | — |
| TE thickness | 0 mm | 0 mm | -0 mm | -33.3% |
| Derived | ||||
| Aspect ratio | 10.266 | 12.696 | +2.429 | +23.7% |
| Area | 218576 mm² | 121109 mm² | -97466 mm² | -44.6% |
| Taper | 0.514 | 0.369 | -0.144 | -28.1% |
| MAC | 151 mm | 104 mm | -47 mm | -31.2% |
| Sections | ||||
| Root section | ag455ct02r | e818 | changed | — |
| Tip section | ag47ct02r | — | changed | — |
| Shapedeviation at matched span fractions, 64 samples | ||||
| Chord deviation (max) | 53 mm | |||
| Chord deviation (RMS) | 48 mm | |||
| Twist deviation (max) | 2.50° | |||
| Dihedral deviation (max) | 79 mm | |||
| Tip cap deviation (max) | 147 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×); “Downwind glide foil” integrates to CL 0.061 against the polar’s CL at the same α (this analysis predates the loading reporting its own) 0.446 (0.14×). 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 | Downwind glide foil |
|---|---|---|
| 8.75 | 13.28 | 23.32 |
| 9.60 | 16.67 | 29.03 |
| 9.91 | 17.20 | 31.15 |
| 10.45 | 18.11 | 32.16 |
| 11.27 | 18.89 | 33.73 |
| 11.30 | 18.91 | 33.73 |
| 12.15 | 19.30 | 33.52 |
| 12.64 | 19.33 | 33.40 |
| 13.00 | 19.35 | 32.99 |
| 13.85 | 19.11 | 32.03 |
| 14.00 | 19.03 | 31.87 |
| 14.70 | 18.62 | 30.72 |
| 15.36 | 18.12 | 29.65 |
| 15.55 | 17.97 | 29.28 |