Piper J-3 Cub — a rectangular wing that worksvsDrela SuperGee II — a 1.5 m discus-launch glider, drawn to the plan
root section usa35b → ag455ct02r · tip section — → ag47ct02r · dihedral 1.00° → 4.00° · area 16577850 mm² → 218576 mm² · tip chord 1545 mm → 94 mm · mac 1545 mm → 151 mm
units
These analyses are not directly comparable
- different trim loads (5396 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.
- Piper J-3 Cub — a rectangular wing that works
- Drela SuperGee II — a 1.5 m discus-launch glider, drawn to the plan
What changed
| Property | Piper J-3 Cub | Drela SuperGee II | Change | % |
|---|---|---|---|---|
| Geometry | ||||
| Span | 10730 mm | 1498 mm | -9232 mm | -86.0% |
| Root chord | 1545 mm | 183 mm | -1362 mm | -88.2% |
| Tip chord | 1545 mm | 94 mm | -1451 mm | -93.9% |
| Sweep parameter | 0.000 | 3.400 | +3.400 | — |
| Dihedral | 1.00° | 4.00° | +3.00° | +300.0% |
| TE thickness | 3 mm | 0 mm | -3 mm | -90.0% |
| Sections | 40 | 30 | -10 | -25.0% |
| Tip cap reach | 0.300 | 0.400 | +0.100 | +33.3% |
| Derived | ||||
| Aspect ratio | 6.945 | 10.266 | +3.321 | +47.8% |
| Area | 16577850 mm² | 218576 mm² | -16359274 mm² | -98.7% |
| Taper | 1.000 | 0.514 | -0.486 | -48.6% |
| MAC | 1545 mm | 151 mm | -1394 mm | -90.2% |
| Sections | ||||
| Root section | usa35b | ag455ct02r | changed | — |
| Tip section | — | ag47ct02r | changed | — |
| Shapedeviation at matched span fractions, 64 samples | ||||
| Chord deviation (max) | 1451 mm | |||
| Chord deviation (RMS) | 1399 mm | |||
| Twist deviation (max) | 0.00° | |||
| Dihedral deviation (max) | 41 mm | |||
| Tip cap deviation (max) | 4925 mm | |||
Performance
CoefficientsDimensionless — how good the shape is, independent of size and speed.
Spanwise
withheld — “Piper J-3 Cub” integrates to CL 0.002 against the polar’s CL at the same α (this analysis predates the loading reporting its own) 0.330 (0.01×); “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 | Piper J-3 Cub | Drela SuperGee II |
|---|---|---|
| 0.014 | 0.374 | 0.259 |
| 0.015 | 0.378 | 0.264 |
| 0.016 | 0.398 | 0.290 |
| 0.017 | 0.430 | 0.327 |
| 0.017 | 0.437 | 0.334 |
| 0.019 | 0.469 | 0.371 |
| 0.021 | 0.511 | 0.415 |
| 0.022 | 0.520 | 0.425 |
| 0.026 | 0.585 | 0.491 |
| 0.027 | 0.605 | 0.509 |
| 0.032 | 0.667 | 0.574 |
| 0.036 | 0.729 | 0.627 |
| 0.041 | 0.775 | 0.681 |
| 0.053 | 0.894 | 0.758 |
| 0.062 | 0.968 | 0.819 |