Downwind glide foil — high aspect reference front wingvsMIT Daedalus 88 — the 34 m human-powered wing
root section e818 → dae11 · tip section — → dae31 · area 121109 mm² → 31712462 mm² · span 1240 mm → 34100 mm · tip chord 48 mm → 762 mm · mac 104 mm → 939 mm
units
These analyses are not directly comparable
- different fluids (water-salt vs air) — density and viscosity both differ, so the drag numbers are not on the same footing
- different trim loads (932 N vs 1020 N) — each wing is carrying a different weight
The geometry comparison below is unaffected — it is a comparison of shapes, not of runs.
- Downwind glide foil — high aspect reference front wing
- MIT Daedalus 88 — the 34 m human-powered wing
What changed
| Property | Downwind glide foil | MIT Daedalus 88 | Change | % |
|---|---|---|---|---|
| Geometry | ||||
| Span | 1240 mm | 34100 mm | +32860 mm | +2650.0% |
| Root chord | 130 mm | 1050 mm | +920 mm | +707.7% |
| Tip chord | 48 mm | 762 mm | +714 mm | +1487.5% |
| Sweep parameter | 9.717 | 0.484 | -9.233 | -95.0% |
| Dihedral | -2.50° | 1.00° | +3.50° | -140.0% |
| Tip twist | -2.50° | -1.50° | +1.00° | -40.0% |
| TE thickness | 0 mm | 2 mm | +1 mm | +650.0% |
| Sections | 30 | 40 | +10 | +33.3% |
| Tip cap reach | 0.400 | 0.250 | -0.150 | -37.5% |
| Derived | ||||
| Aspect ratio | 12.696 | 36.667 | +23.971 | +188.8% |
| Area | 121109 mm² | 31712462 mm² | +31591352 mm² | +26085.0% |
| Taper | 0.369 | 0.726 | +0.356 | +96.5% |
| MAC | 104 mm | 939 mm | +835 mm | +801.6% |
| Sections | ||||
| Root section | e818 | dae11 | changed | — |
| Tip section | — | dae31 | changed | — |
| Shapedeviation at matched span fractions, 64 samples | ||||
| Chord deviation (max) | 920 mm | |||
| Chord deviation (RMS) | 835 mm | |||
| Twist deviation (max) | 1.13° | |||
| Dihedral deviation (max) | 325 mm | |||
| Tip cap deviation (max) | 16520 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 — “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×); “MIT Daedalus 88” integrates to CL 0.120 against the polar’s CL at the same α (this analysis predates the loading reporting its own) 0.913 (0.13×). 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 (water (sea), air)
data
| V (kt) | Downwind glide foil | MIT Daedalus 88 |
|---|---|---|
| 11.54 | 33.67 | 37.99 |
| 12.61 | 33.40 | 43.38 |
| 12.64 | 33.40 | 43.47 |
| 13.68 | 32.23 | 46.93 |
| 14.00 | 31.87 | 47.63 |
| 14.74 | 30.65 | 49.26 |
| 15.36 | 29.65 | 49.23 |
| 15.81 | 28.78 | 49.21 |
| 16.72 | 27.04 | 47.26 |
| 16.88 | 26.73 | 46.91 |
| 17.95 | 24.67 | 43.90 |
| 18.08 | 24.41 | 43.55 |
| 19.01 | 22.65 | 41.08 |
| 19.44 | 21.85 | 40.00 |
| 20.08 | 20.76 | 38.37 |
| 20.80 | 19.54 | 36.58 |
| 21.15 | 19.00 | 35.71 |