Payload fairing Ø92 mm × 205 mm — single page (all sims & visuals)

Order: newest first (highest v number). v2–v4: constant-diameter cylinder; v1 classic power-law; v5–v10 hand-tuned stagnation chain; v11–v30 scripted series (run_fairing_series.py, mutates from best classic Cd). Best classic taper (v5+): v15 Cd 0.0264. Lowest Cd in table (often v2/v4, different Aref): v34 Cd 0.0566.

Machine-readable results: fairing_results.json, fairing_extra_runs.json. v34 (uploaded STL): payload_fairing_v34_report.html. STL Z-color: render_payload_fairing_viz.py; pressure: foamToVTK + render_pressure_pair.py (pvpython).

Simulation setup (common)

OpenFOAM 13, steady incompressible RANS, SST k–ω, freestream −Z, ρ = 1.225 kg/m³, 150 km/h (41.6667 m/s), 300 iterations. forceCoeffs on wingGroup; Aref, lRef from simulate.sh.

CFD results — comparison (150 km/h), newest first

Revision	Cd	Cl	Drag (N)	Aref (m²)	lRef (m)	Mesh cells	Case folder
v36	0.3272	−0.034258	2.845	0.00805	0.435	256 030	`payload_fairing_205x92mm_v36_sim`
v35	0.0567	−0.000001	0.504	0.00823	0.430	241 892	`payload_fairing_205x92mm_v35_sim`
v34	0.0566	0.000001	0.504	0.00823	0.430	242 412	`payload_fairing_205x92mm_v34_sim`
v33	0.0720	−0.000000	0.587	0.00754	0.401	232 360	`payload_fairing_205x92mm_v33_sim`
v32	0.0798	−0.000082	0.766	0.00889	0.385	225 559	`payload_fairing_205x92mm_v32_sim`
v31	0.0757	0.000010	0.735	0.00899	0.385	224 429	`payload_fairing_205x92mm_v31_sim`
v30	0.1445	0.035390	1.177	0.00754	0.393	240 247	`payload_fairing_205x92mm_v30_sim`
v29	0.1557	−0.003509	1.268	0.00754	0.393	240 260	`payload_fairing_205x92mm_v29_sim`
v28	0.2056	−0.050066	1.674	0.00754	0.392	240 459	`payload_fairing_205x92mm_v28_sim`
v27	0.1998	−0.001570	1.627	0.00754	0.394	240 877	`payload_fairing_205x92mm_v27_sim`
v26	0.2195	−0.017879	1.788	0.00754	0.394	240 318	`payload_fairing_205x92mm_v26_sim`
v25	0.1663	0.001008	1.354	0.00754	0.393	239 996	`payload_fairing_205x92mm_v25_sim`
v24	0.1444	0.035354	1.176	0.00754	0.393	240 245	`payload_fairing_205x92mm_v24_sim`
v23	0.1333	0.030287	1.086	0.00754	0.393	240 249	`payload_fairing_205x92mm_v23_sim`
v22	0.1091	0.000054	0.888	0.00754	0.393	240 159	`payload_fairing_205x92mm_v22_sim`
v21	0.1603	−0.003252	1.306	0.00754	0.393	240 181	`payload_fairing_205x92mm_v21_sim`
v20	0.1331	0.030237	1.084	0.00754	0.393	240 611	`payload_fairing_205x92mm_v20_sim`
v19	0.1122	−0.001320	0.914	0.00754	0.393	240 179	`payload_fairing_205x92mm_v19_sim`
v18	0.1329	0.030274	1.082	0.00754	0.393	240 395	`payload_fairing_205x92mm_v18_sim`
v17	0.1650	−0.022331	1.344	0.00754	0.393	240 151	`payload_fairing_205x92mm_v17_sim`
v16	0.2046	−0.007488	1.667	0.00754	0.392	240 404	`payload_fairing_205x92mm_v16_sim`
v15	0.1333	0.030287	1.086	0.00754	0.393	240 275	`payload_fairing_205x92mm_v15_sim`
v14	0.1887	−0.018843	1.537	0.00754	0.391	240 419	`payload_fairing_205x92mm_v14_sim`
v13	0.1889	−0.023780	1.538	0.00754	0.391	240 581	`payload_fairing_205x92mm_v13_sim`
v12	0.2159	−0.008102	1.758	0.00754	0.390	240 403	`payload_fairing_205x92mm_v12_sim`
v11	0.2036	−0.022559	1.658	0.00754	0.392	240 764	`payload_fairing_205x92mm_v11_sim`
v10	0.1967	−0.004272	1.602	0.00754	0.391	240 525	`payload_fairing_205x92mm_v10_sim`
v9	0.2018	−0.016936	1.643	0.00754	0.385	234 486	`payload_fairing_205x92mm_v9_sim`
v8	0.2024	0.016148	1.649	0.00754	0.385	234 198	`payload_fairing_205x92mm_v8_sim`
v7	0.2205	0.032131	1.796	0.00754	0.375	233 004	`payload_fairing_205x92mm_v7_sim`
v6	0.2268	−0.040738	1.847	0.00754	0.365	221 410	`payload_fairing_205x92mm_v6_sim`
v5	0.2249	−0.100262	1.832	0.00754	0.365	221 414	`payload_fairing_205x92mm_v5_sim`
v4	0.0864	0.000003	0.704	0.00754	0.387	226 839	`payload_fairing_205x92mm_v4_sim`
v3	0.0992	0.000121	0.928	0.00866	0.397	231 359	`payload_fairing_205x92mm_v3_sim`
v2	0.0860	0.000107	0.700	0.00754	0.385	226 925	`payload_fairing_205x92mm_v2_sim`
v1	0.2327	−0.081702	1.895	0.00754	0.355	220 277	`payload_fairing_205x92mm_sim`

Cd/Cl averaged over last 50 time steps; drag = Cd × ½ρU²Aref. v2–v4 not directly comparable to tapering shells by Cd alone (different Aref convention).

Additional runs (separate cases, other speeds)

Same fairing family where noted; distinct OpenFOAM case directory and mesh when the STL path name differs.

Label	Cd	Cl	Drag (N)	Aref (m²)	lRef (m)	Mesh cells	Speed	Iterations	Case folder
v2-300	0.0125	0.000020	1.994	0.03773	0.385	226 925	83 m/s	300	`payload_fairing_205x92mm_v2-300_sim`

v2-300 — surface (83 m/s)

v2-300 — volume slice Y = 0 (83 m/s)

CFD pressure (150 km/h), newest first

v36 — surface

v36 — volume slice (Y = 0)

v35 — surface

v35 — volume slice (Y = 0)

v34 — surface

v34 — volume slice (Y = 0)

v33 — surface

v33 — volume slice (Y = 0)

v32 — surface

v32 — volume slice (Y = 0)

v31 — surface

v31 — volume slice (Y = 0)

v30 — surface

v30 — volume slice (Y = 0)

v29 — surface

v29 — volume slice (Y = 0)

v28 — surface

v28 — volume slice (Y = 0)

v27 — surface

v27 — volume slice (Y = 0)

v26 — surface

v26 — volume slice (Y = 0)

v25 — surface

v25 — volume slice (Y = 0)

v24 — surface

v24 — volume slice (Y = 0)

v23 — surface

v23 — volume slice (Y = 0)

v22 — surface

v22 — volume slice (Y = 0)

v21 — surface

v21 — volume slice (Y = 0)

v20 — surface

v20 — volume slice (Y = 0)

v19 — surface

v19 — volume slice (Y = 0)

v18 — surface

v18 — volume slice (Y = 0)

v17 — surface

v17 — volume slice (Y = 0)

v16 — surface

v16 — volume slice (Y = 0)

v15 — surface

v15 — volume slice (Y = 0)

v14 — surface

v14 — volume slice (Y = 0)

v13 — surface

v13 — volume slice (Y = 0)

v12 — surface

v12 — volume slice (Y = 0)

v11 — surface

v11 — volume slice (Y = 0)

v10 — surface

v10 — volume slice (Y = 0)

v9 — surface

v9 — volume slice (Y = 0)

v8 — surface

v8 — volume slice (Y = 0)

v7 — surface

v7 — volume slice (Y = 0)

v6 — surface

v6 — volume slice (Y = 0)

v5 — surface

v5 — volume slice (Y = 0)

v4 — surface

v4 — volume slice (Y = 0)

v3 — surface

v3 — volume slice (Y = 0)

v2 — surface

v2 — volume slice (Y = 0)

v1 — surface

v1 — volume slice (Y = 0)

Geometry (STL, Z height), newest first

ParaView on STL only.

v36

v35

v34

v33

v32

v31

v30

v29

v28

v27

v26

v25

v24

v23

v22

v21

v20

v19

v18

v17

v16

v15

v14

v13

v12

v11

v10

v9

v8

v7

v6

v5

v4

v3

v2

v1

Downloads (STL), newest first

payload_fairing_205x92mm_v2-300.stl — v2 geometry @ 83 m/s, 300 iterations (v2-300)
payload_fairing_205x92mm_v36.stl — v36 — nose 145.2 mm, tail 85.0 mm, tip linear 0.040
payload_fairing_205x92mm_v35.stl — v35 — params
payload_fairing_205x92mm_v34.stl — v34 — aref column = simulate.sh Y×Z; frontal −Z uses X–Y; see payload_fairing_v34_report.html
payload_fairing_205x92mm_v33.stl — v33 — nose 118.0 mm, tail 78.0 mm
payload_fairing_205x92mm_v32.stl — v32 — smoother axial bulge vs v31 sin²; finer sampling + 128 revolve
payload_fairing_205x92mm_v31.stl — v31 — teardrop: widest at payload mid, same cavity as v2
payload_fairing_205x92mm_v30.stl — v30 — nose 122.0 mm, tail 66.0 mm, tip linear 0.104
payload_fairing_205x92mm_v29.stl — v29 — nose 122.0 mm, tail 66.0 mm, tip linear 0.124
payload_fairing_205x92mm_v28.stl — v28 — nose 121.0 mm, tail 66.0 mm, tip linear 0.112
payload_fairing_205x92mm_v27.stl — v27 — nose 123.4 mm, tail 66.0 mm, tip linear 0.112
payload_fairing_205x92mm_v26.stl — v26 — nose 122.5 mm, tail 66.0 mm, tip linear 0.116
payload_fairing_205x92mm_v25.stl — v25 — nose 122.0 mm, tail 66.0 mm, tip linear 0.112
payload_fairing_205x92mm_v24.stl — v24 — nose 122.0 mm, tail 66.0 mm, tip linear 0.112
payload_fairing_205x92mm_v23.stl — v23 — nose 122.0 mm, tail 66.0 mm, tip linear 0.112
payload_fairing_205x92mm_v22.stl — v22 — nose 122.0 mm, tail 66.0 mm, tip linear 0.112
payload_fairing_205x92mm_v21.stl — v21 — nose 122.0 mm, tail 66.0 mm, tip linear 0.112
payload_fairing_205x92mm_v20.stl — v20 — nose 122.0 mm, tail 66.0 mm, tip linear 0.112
payload_fairing_205x92mm_v19.stl — v19 — nose 122.0 mm, tail 66.0 mm, tip linear 0.112
payload_fairing_205x92mm_v18.stl — v18 — nose 122.0 mm, tail 66.0 mm, tip linear 0.112
payload_fairing_205x92mm_v17.stl — v17 — nose 122.0 mm, tail 66.0 mm, tip linear 0.112
payload_fairing_205x92mm_v16.stl — v16 — nose 122.0 mm, tail 64.5 mm, tip linear 0.112
payload_fairing_205x92mm_v15.stl — v15 — nose 122.0 mm, tail 66.0 mm, tip linear 0.112
payload_fairing_205x92mm_v14.stl — v14 — nose 122.0 mm, tail 64.0 mm, tip linear 0.104
payload_fairing_205x92mm_v13.stl — v13 — nose 122.0 mm, tail 64.0 mm, tip linear 0.112
payload_fairing_205x92mm_v12.stl — v12 — nose 121.0 mm, tail 64.0 mm, tip linear 0.100
payload_fairing_205x92mm_v11.stl — v11 — nose 123.4 mm, tail 64.0 mm, tip linear 0.100
payload_fairing_205x92mm_v10.stl — v10
payload_fairing_205x92mm_v9.stl — v9
payload_fairing_205x92mm_v8.stl — v8
payload_fairing_205x92mm_v7.stl — v7
payload_fairing_205x92mm_v6.stl — v6
payload_fairing_205x92mm_v5.stl — v5
payload_fairing_205x92mm_v4.stl — v4
payload_fairing_205x92mm_v3.stl — v3
payload_fairing_205x92mm_v2.stl — v2
payload_fairing_205x92mm.stl — v1 classic

Optimization notes

v33: New subsonic “rocket teardrop” baseline — elliptic ogive nose, constant 49 mm OD payload bay, elliptic boat-tail; high fineness ratio (~4.1 length / max diameter), smooth G¹ shoulders (standard low–subsonic practice).
v11–v30: Each revision mutates FairingParams from the current global lowest-Cd classic taper (seed v10), 16-phase cycle; worse runs do not advance best_params (next version still mutates from the best-so-far).
v5–v10: Hand-tuned chain from v1 targeting stagnation; see earlier commit messages / git history.

Pipeline: scripts/run_fairing_series.py, scripts/fairing_parametric.py, simulate.sh.