Chapter 4: Stealth, Sensors & Hardpoints

Created by Sarah Choi (prompt writer using ChatGPT)

Stealth, Sensors & Hardpoints for Vehicle Concept Artists — Air Vehicles: Fixed‑Wing

Stealth, sensing, and payload attachment form the triangle that decides how a fixed‑wing aircraft is seen, what it can see, and what it can carry. For vehicle concept artists—on both the concepting and production sides—integrating those three without contradictions is the craft that makes fighters feel inevitable, transports dependable and interoperable, and gliders purposeful rather than bare. This article explains practical stealth shaping, sensor integration, and hardpoint logic for fighters, transports, and gliders, and translates those choices into buildable packages your modeling, rigging, physics, VFX, audio, and UI partners can trust.

Stealth: what you can “design in”

Stealth is not invisibility; it is signature management across radar (RCS), infrared (IR), visual, and acoustic bands. Conceptually, stealth shaping aims to control where energy goes. In practice, that means:

Planform alignment. Align leading and trailing edges of wings, tails, and bays into a small set of azimuth angles so specular returns migrate into a few lobes. Fighters use faceted or continuous‑curvature surfaces with edge families that repeat; transports and gliders borrow milder alignment to reduce frontal RCS without hurting efficiency.

Edge and gap discipline. Doors, panels, and control surfaces should maintain edge families; sawtooth edges, scarfed hinges, and RAM (radar‑absorbent material) gaskets manage seams. Avoid random panel breaks along silhouette edges. Place screws and fasteners under fairings or within edge treatments.

Inlet and fan management. Radar sees compressor faces well. Fighters hide fans with S‑ducts and blocker vanes or use diverterless supersonic inlets (DSI) to shed boundary layer. Transports can recess fans, add blocker grids, and use RAM linings. Gliders and motor‑gliders avoid large openings; sustainer inlets are tiny and flush.

Exhaust IR and radar. Cool, mix, and mask. Fighters use convergent‑divergent nozzles with film cooling and sometimes vectoring paddles; serrated (chevron) edges reduce noise and signature on transports. Transports shroud hot cores inside high‑bypass flows. For all, keep hot plumes away from surfaces you want cool (tailplanes, sensors).

Corner reflectors and cavities. Right‑angle corners and deep cavities (bays, intakes, landing‑gear wells) bounce radar back. Use ramps, lips, and shields to break up corner reflectors, and apply RAM selectively. On transports, fair door interiors and keep cargo door seams aligned with edge families.

Materials and coatings. RAM paints, radar‑loss foams in leading edges, serrated panel overlaps; IR signature paints near exhausts; low‑gloss visual coatings. Specify in material guides which panels are “RAM critical” vs. ordinary.

Acoustic. Chevrons, mixer ejectors, and lining in nacelles; gear door seals and anti‑rattle; smooth flap track fairings. Useful for transports operating near cities and gliders with sustainer props.

From production, stealth shows up as rules and tolerances: edge angles (in degrees), maximum gap widths, hinge offsets, door sawtooth pitch, inlet lip radii, allowable fastener exposure, and coating zones. Orthos and callouts must freeze those numbers so modeling doesn’t drift.

Sensors: how the aircraft perceives and communicates

Sensors define role. Fit them where they can see, cool, and survive.

Fighters.

  • Primary radar: AESA behind a dielectric radome (nose or chin). If stealthy, radome seam lines align with edge families; include lightning diverter traces subtly.
  • IRST/EOTS: Infrared search/track or electro‑optical targeting in a chin/cheek window; cooled and gimballed. Provide clear arcs and service doors.
  • EW/ESM: Antenna arrays along leading/trailing edges, tail tips, and cheek chines; flush apertures or conformal arrays. Place RWR (radar warning) apertures at quadrants with unobstructed views.
  • Datalinks/comm/SATCOM: Low‑profile blades or conformal bumps. On stealth builds, embed in edge families and use conformal housings.
  • Distributed aperture systems (DAS): Multiple IR cameras arranged for spherical coverage—fore, aft, belly, shoulders. Ensure non‑overlap and cooling.

Transports.

  • Weather radar: Large radome in the nose; clear sweep. Add lightning diverter strips and access panel.
  • Terrain following/avoidance: Antennas under belly; forward‑looking IR turrets on special‑mission variants.
  • Satcom/comm: SATCOM fairings (“humps”) on the back; VHF/UHF blades; HF longwires/towel‑racks on some.
  • EO/IR turrets: Under‑nose or belly balls for SAR/ISR variants; ensure field‑of‑regard avoids gear doors and cargo ramps.
  • Nav aids: ILS/VOR/marker antennas; GPS pucks; ADF loops on legacy.

Gliders & research platforms.

  • Scientific pods: Wingtip or belly pods for lidar, hyperspectral cameras, magnetometers; fairings must preserve laminar flow where possible.
  • Probe booms: Long nose booms with pitot/static and gust probes; mass‑balanced mounts.

Sensors bring cooling and maintenance: heat pipes, ECS taps, access panels, window heaters/defoggers, anti‑icing. Production callouts should bind power, cooling, and de‑ice routes; orthos must show fields of regard with keep‑out cones.

Hardpoints: how payload connects without lying

Hardpoints are structure + systems + aerodynamics. They must land on spars or strong frames, carry plumbing and data, and not shred stealth or laminar flow without reason.

Families of carriage.

  • Internal bays (fighters): main and side bays keep signatures low. Doors can be clamshell, scissor, or banana style; ejection racks (BRU‑style) push stores into the airstream. Concepts must show door style, actuator location, and clearance for fins/seekers.
  • Conformal weapon/fuel bays (CWB/CFTs): Bulged fairings that preserve edge alignment; limited door seams; good for transports or fighters seeking range with modest signature penalty.
  • External pylons: Standard solution for transports and non‑stealth fighters. Pylons mount to wing spars; include plugs for when removed. Provide stores management umbilicals, pressurization or anti‑ice if near engines, and jettison clearances.
  • Fuselage stations: Centerline pylons on fighters and transports; good for pods (targeting, recon, ECM).
  • Wingtip rails/pods: Missiles, ECM pods, or research tips; reduce vortex drag in some cases but affect flutter.

Loads & interfaces. Every station needs SWL (safe working load), ejector stroke, pitch/yaw cant, and plumbing (fuel for tanks, high‑pressure air, coolant) where applicable. Add MAU/1553 or relevant data buses in callouts.

Doors & flow. If you mount an EO/IR turret or refuelling probe near a bay, door arcs must not blind or cook the sensor. Flap tracks and spoilers must clear pylons at deflection. Production orthos must freeze hinge lines and bay geometry relative to these.

Glider hardpoints. Use pylonlets for sensor pods with quick‑release pins; maintain laminar flow—mount on spar stations and provide fairings that blend smoothly. For motor‑gliders, ensure props/doors don’t collide with pod sightlines.

Fighters: reconcile stealth, sensors, and stores

Fighters achieve the triangle by choosing a stealth regime first, then threading sensors and stores through the available edges and bays.

  • Stealth‑forward: Internal bays for A2A/A2G weapons; DSI or S‑duct inlets; faceted doors; conformal DAS windows; retractable refuelling probe or stealthy receptacle; limited external pylons used only in permissive missions, with RAMed pylon shapes and aligned edges.
  • Multirole balanced: Moderate planform alignment; external pylons standard; sensors in cheeks/chin; IRST fairing ahead of the canopy; centerline targeting pod. In both: lock bay volume early (fin spans, weapon lengths), choose door style, and place ejector racks. Call out sensor cooling taps and avoid exhaust wash onto windows. Rigging needs door sequences (open → eject → close) and interlocks with gear/flaps. VFX anchors: bay door vortices, nozzle heat, DAS glints, seeker glows.

Transports: interoperability and mission kits

Transports carry pods, tanks, pallets, and defensive aids.

  • Hardpoints: Under‑wing pylons sized for pods (jammers, refuelling drogues), ferry tanks, or rescue gear. Use standard lug spacings (e.g., NATO 14‑inch).
  • Cargo systems: Palletized mission kits (ISR racks, comms nodes) interfacing with power/cooling buses and hatch antennas (SATCOM).
  • Defensive aids: MAWS/CMWS sensors on corners; chaff/flare buckets near tail; DIRCM turrets with clear aft cones. Place them to avoid engine plume.
  • Refuelling: Boom receptacle on spine or probe on nose/cheek; structural reinforcements and doors; lights for night ops. Production packages must define pylon attach points on spars, allowable pod sizes, ramp clearances, and wiring/cooling routes. Camera reads should anchor nav/anti‑collision lights, formation “slime” lights, and defensive sensor glints without adding edge LEDs that smear planform.

Gliders: pure air with purposeful add‑ons

Gliders value laminar flow and weight. Any sensor or hardpoint must sit on structure with minimal disturbance.

  • Pods: Slender, teardrop pods at the spar; fairings with smooth fore‑aft blend; removable for competitions.
  • Tow & release: Nose hooks and belly releases; clear approach for tow rope; labels and safety flags.
  • Sustainers: Folding prop doors/panels flush; minimal inlets/exhausts; keep windows clean of exhaust streaks. Production orthos should show boundary layer trips, inspection panels, and pod removal pins. VFX sparse; audio focuses on whistle changes with spoilers and pod doors.

UI & workflow reads (diegetic)

  • Stealth state: discreet panel lamps, cockpit symbology; avoid exterior “stealth on” lights.
  • Sensor state: tiny tell‑tales—IRST window glints, turret posture, radome heating lines; ground crew panels with BIT (built‑in test) lamps.
  • Stores state: safe/hot flags on pins/covers; bay armed indicators near doors (internal, diegetic for ground only).

Concept → production deliverables

  • Stealth rule sheet: edge families (in degrees), gap/fastener limits, door sawtooth pitch, inlet family (DSI/ramp/S‑duct), nozzle type, RAM/IR coating zones.
  • Sensor map: fields of regard, cooling/power taps, window materials and heaters, maintenance panels, keep‑out cones relative to doors/gear/flaps/exhaust.
  • Hardpoint layout: station numbers, SWL, ejector stroke, cant angles, plumbing/data buses, door sequences (for bays), jettison envelopes.
  • Metrics sheet: bay volumes (L×W×H), weapon/pod dimensional limits, antenna fairing sizes, radome diameter, SATCOM fairing heights, DIRCM cone angles.
  • Orthos (measured): plan/side/front with edge alignment guides, bay doors and hinge axes, sensor window locations, pylon attach points on spars, tip rails, and pod placements.
  • Cutaway: inlet S‑duct/blockers, bay frames and ejectors, sensor racks and coolers, wiring/cooling trunks, RAM laminate stacks at edges.
  • Exploded views: bay door module, ejector rack, pylon with umbilical and sway braces, IRST turret with gimbals, SATCOM fairing, DIRCM turret, chaff/flare bucket.
  • Callouts: deflection/door ranges, interlocks (gear/flaps/bays), cooling flow, power loads, safe separation distances, lightning protection paths, coating repair notes.
  • Camera‑read boards: far/mid/near day/night/vapor with “must read” notes (edge families, radome, bay seams, pylon pods) and no LED edge strips guidance.
  • Rig pack: bay sequence timings, turret gimbal limits, pylon jettison/hinge, nozzle/vector schedules, sensor cover doors; VFX/audio sockets (bay vortices, seeker glow, chaff/flare).

Indie vs. AAA cadence

Indie: one evolving canvas per aircraft—stealth rule overlay + sensor map + hardpoint layout—with a compact cutaway and rig strip; validate in engine with simple bay/turret animations.

AAA: gated: stealth planform lock → sensor FOV/cooling lock → hardpoint & bay layout lock → modeling kickoff (orthos/cutaways/callouts) → rig/VFX/audio validation (bay/turret/nozzle) → camera‑read sign‑off; ship a mission kit (bay door modules, ejector racks, pylons, pod fairings, window modules) and a coatings guide for RAM/IR.

Closing

When stealth edges, sensor sightlines, and hardpoint structure agree, the airplane tells the truth before it moves. Fighters project intent without breaking signature, transports advertise capability without clutter, and gliders carry science without losing grace. Encode those truths as rules and coordinates, and your teams will build aircraft that look right, work right, and survive the pipeline.