Defined the 63 in × 1.6 in fairing envelope, led three concept studies and the CoDR, and calculated preliminary drag and thermal screening inputs. The Icarus backup-candidate simulation in Ansys CFD is converged and under review.
Icarus Ansys CFD converged and under review
I lead development of Argo’s external downcomer fairing, setting the shared requirements and analysis plan. I developed preliminary Icarus baseline calculations, screened aerodynamic and thermal loads, investigated mounting and manufacturing options, and led the September 3, 2026 conceptual design review.
I coordinated three concept studies against shared vehicle constraints. Quinn Colleran, Hannah Ruan, and Aaron Lin own the individual concept geometries credited below; I developed the common analysis, integration, and manufacturing trade.
I adapted the component-based approach in missile-design literature for our four-person set-based design effort. Leading-edge, midsection, and boattail studies gave the team a common basis for first-order drag trades at the CoDR before combining promising features. We also considered complete body profiles, whose geometry is defined from front to back rather than assembled from separate regions.
What the diagram means: it identifies the drag mechanisms each region initially brings into focus. The “dominates” labels are a teaching simplification, not a quantified allocation of the fairing’s drag.
Full revolution ≠ mounted fairing: an optimum isolated axisymmetric body does not necessarily remain optimal when only part of that shape is joined to the rocket. Body-junction flow, the upstream boundary layer, attachment details, and nearby fins couple the regions. Published profiles establish candidates; integrated CFD must establish their ranking.
I used the trajectory to prioritize the flight conditions where a drag improvement is most consequential. Drag follows D = q Sref CD, with q = ½ρV²: time at a Mach number alone does not describe its contribution to aerodynamic loading.
The trajectory motivated comparison at Mach 2.0, 2.5, and 2.81 near the high-dynamic-pressure supersonic interval. Other regimes remain in the trade; their drag contribution depends on both dynamic pressure and the changing drag coefficient.
Each designer proposed a complete aerodynamic concept. I coordinated their comparison against shared constraints; none is presented as the selected or validated final fairing.
Concept study: Quinn Colleran
0.66 power-series leading edge, constant semicircular midsection with a body fillet, and a nominal 10° conical boattail. The study balances wave drag, wetted area, and the limited aft envelope.
Concept study: Hannah Ruan
Von Kármán (L-D Haack) leading profile, constant-radius midsection, and a shallow aft taper of approximately 6°. The study uses published supersonic profile comparisons as its starting point.
Concept study: Aaron Lin
0.75 power-series leading edge, constant midsection with a widened, filleted body junction, and a nominal 10° aft chamfer. The study considers attachment area and gradual transitions alongside drag.
My Mach 2.81 Ansys Fluent solve for the legacy Icarus fairing has converged and is under review. Icarus is the comparison baseline and a backup flight candidate; no final fairing or drag improvement has been established.
My Icarus review identified protruding fasteners, uneven surface finish, abrupt transitions, and an aft profile worth revisiting. I consulted the previous builder to connect these observations to practical issues in layup, vacuum consolidation, and wiring integration.
My hand calculations provide a screening baseline, followed by CFD of the actual mounted geometry. The dropdowns retain the inputs, equations, and assumptions so their limits are reviewable.
| Mach number / specific-heat ratio | 2.81 / γ = 1.4 |
|---|---|
| Reynolds number | 2.04 × 10⁸, as recorded in the CoDR |
| Wetted area, Swet | 477 in² |
| Projected reference area, Sref | 7.99 in² |
| Area ratio | Swet / Sref ≈ 59.70 |
| Leading-profile surrogate | Full cone with 15° half-angle; Icarus itself has a wedge-like front. |
The recorded Reynolds number is retained as an input. The length and atmospheric-property basis should accompany the next model comparison. These coefficients use the cover reference area, not the full rocket’s frontal area.
√Cf,0 log₁₀(Re Cf,0) = 0.242
Cf = Cf,0 / [1 + (γ − 1)M² / 2]0.467
CD,f = 1.10 Cf Swet / Sref
| Incompressible turbulent Cf,0 | ≈ 0.001879 |
|---|---|
| Compressibility factor | ≈ 0.6424 |
| Smooth compressible Cf | ≈ 0.001207 |
| Smooth friction-drag contribution | ≈ 0.07205 |
| With book’s 10% preliminary roughness allowance | ≈ 0.07925, reproducing the CoDR’s ≈ 0.0792 |
Cf is normalized by wetted area; CD,f is normalized by the chosen reference area. The smooth turbulent correlation and allowance are screening assumptions, not measurements of this cover’s roughness or junction flow.
S. S. Chin, Missile Configuration Design (1961): p. 64, Eq. 4-2; p. 67, Eqs. 4-6/4-7 and roughness allowance.
Cp = Δp / q = (0.083 + 0.096 / M²)(σ / 10)1.69
| Cone half-angle σ | 15°, entered in degrees |
|---|---|
| Mach number | 2.81 |
| Calculated Cp | ≈ 0.1888 |
The source relates this pressure coefficient to cone pressure drag at zero incidence using the cone’s base area. Its attached-shock cone model does not directly predict the wedge-like Icarus front or its rocket-body junction. The value is a surrogate, not the mounted fairing’s verified CD.
| Boattail term used in CoDR | ≈ 0.006, read from a published typical-boattail correlation |
|---|
The source assumes a sufficiently long cylindrical section ahead of the boattail so flow is approximately uniform at its entrance. The correlation also depends on geometry and reference area. It is not a universal aft-drag value. The original sum also needs consistent definitions of foredrag versus wave drag so friction is not counted twice when substituting a literature foredrag value.
Mounted-flow requirement: Rocket-body interference, boundary-layer flow, and separation can increase drag and disturb the flow reaching the fins. Candidate rankings require a combined fairing/body/fin model on a common reference area; no drag-reduction percentage is claimed from the surrogate calculations.
Chin, p. 30, Fig. 3-14: typical boattail drag; screening method from my CoDR.
Ansys CFD: The legacy Icarus cover simulation is converged and under review. Icarus serves as the comparison baseline and a backup flight candidate.
Icarus baseline domain, mesh, and boundary conditions; pressure/Mach contours, integrated drag, and convergence checks. The Icarus solve has converged; reviewed results will be added here.
I compared carbon-fiber wet layup on printed positive molds with machined insulation-foam tooling, considering cost, internal fit, release, cure conditions, and repeatable surface finish. I also evaluated mold polarity and vacuum consolidation using lessons from the previous cover.
For attachments, I investigated recessed fasteners with a flush surface treatment and underside bonded hardware. The trade includes local laminate thickness, access, load paths, and support along the cover; removing a protruding screw is only useful if the attachment remains practical and structurally sound.
The CoDR established manufacturing options and integration questions. It did not close out the final mold, laminate, or attachment design.
At Mach 2.81 with 236 K ambient air, I calculated approximately 609 K stagnation temperature and 579 K recovery temperature to screen the available epoxy’s temperature capability. These gas-temperature estimates motivated the loaded, heated mounting-coupon test below; they do not predict transient laminate temperature or prove thermal failure.
T₀ = T∞ [1 + (γ − 1)M∞² / 2]
Tlocal = T₀ / [1 + (γ − 1)Mlocal² / 2]
Tr = Tlocal [1 + r(γ − 1)Mlocal² / 2]
At Mach 2.81, static temperature 236 K, and γ = 1.4, the ideal-gas stagnation relation gives approximately 609 K (636°F). A separate recovery estimate used local Mach 2 and a recovery factor of 0.89, giving approximately 579 K (583°F).
Exposure duration, heat transfer, laminate construction, and the specific cured resin still need to be assessed. The CoDR’s roughly 120–125°F epoxy limit is a preliminary material assumption to confirm for the selected resin and cure.
Reference: NASA Glenn isentropic flow relations.
I am designing a curved carbon-fiber coupon with a bolted interface, held under sustained load while heated, to observe local dimpling and loss of attachment stiffness. This will inform a conservative operating limit for that configuration; testing and final material selection remain pending.
Source: Aerocover Design Doc; Argo Aerocover CoDR, September 3, 2026; S. S. Chin, Missile Configuration Design (1961); and current baseline-analysis work. Concept authorship is retained above; legacy hardware and reference illustrations are identified in captions.
The nosecone belongs to the separation and recovery subsystem; this section documents the aerodynamic comparison. Any selected shape must also preserve the recovery packaging and deployment interfaces.
The fairing trade led me to investigate the vehicle’s nosecone using RASAero II. I swept nine profile families and tip-radius inputs for Argo’s 40 in long, 8 in diameter nosecone (L/D = 5), then repeated the comparison at L/D = 3 to investigate a ranking difference from the published foredrag curves used in our CoDR.
RASAero II screening predicted approximately 1.1% higher apogee for the ¾-power and Von Kármán profiles than the tangent-ogive baseline. These whole-vehicle outputs do not isolate nose drag; a common-input, drag-coefficient, and stability comparison remains pending.
No replacement nosecone has been selected. The sweep and tip-radius sensitivity are retained below as preliminary simulation evidence.
Current geometry: 40 in length, 8 in diameter, 0.11 in tip radius. Values below are recorded flight-simulation outputs; they have not been independently rerun or validated by CFD.
| Profile | Predicted apogee | Change from tangent ogive |
|---|---|---|
| Tangent ogive (current) | 87,966 ft | Baseline |
| Conical | 88,227 ft | +261 ft / +0.30% |
| Von Kármán | 88,927 ft | +961 ft / +1.09% |
| ¾ power | 88,954 ft | +988 ft / +1.12% |
Input sensitivity: changing the tangent-ogive tip radius from the initial 1 in input to the current 0.11 in input changed predicted apogee from 82,314 to 87,966 ft (+5,652 ft). This is a simulation-input comparison, not a measured gain from modifying hardware.
L/D = 3 check: the conical input produced the highest recorded apogee, while the worksheet explicitly notes possible instability and center-of-pressure effects. The workbook records apogee for these cases, not nose-only CD versus Mach or stability histories, so it does not yet resolve the discrepancy.
Next comparison: extract aerodynamic coefficients over Mach, separate the contributions to drag, and examine stability histories before matching the simulation to the paper’s zero-angle-of-attack foredrag data. The relative importance of each Mach range must then be evaluated over the flight trajectory.
Source: my “Nosecone Sim Investigation” worksheet, current-tip-radius cases and L/D = 3 sweep. Literature: NACA Report 1386, Perkins, Jorgensen & Sommer (1958). Simulation tool: RASAero II.