Everything the design calls for
Ten subsystems, a weight budget that closes, and a status tag on every line: buy exists off the shelf, build is engineering we must do, research needs a result we do not have yet.
Five layers
Pilot
Intent, not angles. Throttle, point, abort.
Flight control system
Envelope protection, G-LOC guard, fault management, automated landing. Dual computers, ≥ 500 Hz inner loop. To be built.
Life support
G-suit, cooling, O2, biometrics, helmet environment.
Propulsion and power
5 turbines, fuel, alternators, battery.
Structure and armor
Exoframe, shell, recovery systems.
The budget that decides everything
All-up weight target 160 kg with an 80 kg pilot. Five 550 N engines give 2,750 N, a thrust-to-weight of 1.75. Lose one engine and 2,200 N still exceeds the 1,570 N needed to hover.
| Item | Mass | Status |
|---|---|---|
| Pilot, clothed | 80 kg | — |
| Engines, 5 × micro-turbine incl. mounts and containment | 27 kg | buy |
| Fuel, Jet A-1, usable | 20 kg | buy |
| Fuel system, tank, pumps, lines, shutoffs | 4 kg | build |
| Exoframe, CFRP + 7075 Al | 9 kg | build |
| Shell: Phase 1 carbon + CE armor · Phase 4 CMF torso + helmet | 6 kg · 10 kg | build · research |
| Helmet, HUD, audio, sensors in helmet | 2.5 kg | build |
| Avionics, flight computers, IMUs, GNSS, radar alt, LIDAR, cameras | 3 kg | buy |
| Arc core: alternators, 1.2 kWh battery, power distribution | 5.5 kg | build |
| Life support: G-suit, compressor, cooling garment + pump, O2 2 L, heated layer | 6 kg | buy |
| Recovery: ballistic chute, airbag system | 6 kg | buy |
| Actuators (gimbals), wiring, telemetry, black box | 4 kg | build |
| All-up weight | ~160 kg (Phase 4 with CMF ~165 kg) |
Endurance reality. Twenty minutes of electric flight would need ~50 kWh of battery, over 200 kg at today’s energy density. Kerosene has 40× the energy per kilogram. The MK-I is a turbine suit until battery chemistry changes, and every page on this site assumes 8–12 minute sorties.
Five micro gas turbines
Engine
Class reference: JetCat P550-PRO-GH or equivalent. ~550 N thrust, ~5 kg each, kerosene with 5% turbine oil, full-authority digital engine control over CAN, brushless starter-generator. buy
| Thrust, each | 550 N (56 kgf) |
| Max rpm | ~90,000 |
| Exhaust gas temperature | 650–720 °C |
| Spool, idle → 100% | ~3 s · 40 ms for ±10% around setpoint |
| Fuel burn at 100% | ~0.55 kg/min each |
| Starter-generator | ~500 W electrical each, feeds the arc core |
Slow spool is why thrust vectoring, not throttle, does the fast control. The gimbals move in 40 ms; the engines do not.
Layout and vectoring
- 2 back pods on a rigid dorsal frame, ±30° two-axis gimbals (brushless servo). Primary climb and cruise thrust, 1,100 N.
- 2 boot jets on calf frames, ±20° gimbals. Hover and landing, 1,000 N.
- 2 arm thrusters of 300 N on the forearms; the arms are the gimbal. Fine control, yaw, braking. Arm units are 300 N class so a tired pilot can still hold them.
- Any single failure leaves a thrust centroid the controller can re-trim with the remaining gimbals. Verified in simulation for all 5 single-engine-out cases and the 2 worst dual cases before first free hover.
- Intakes forward and above all nozzles in every attitude from upright to prone. Intake screens. Kevlar burst containment on each engine.
Fuel system
Crash-resistant bladder tank (20 kg usable) in the lower back, as low and central as possible. Dual electric pumps, per-engine solenoid shutoff, coarse and fine filters with water trap, fuel-flow and level sensors to the controller. Breakaway self-sealing fittings at every engine. Fuel shutoff fires automatically on: ABORT, impact (> 8 g on the frame IMU), tilt > 90° with weight on the feet, fire detection (thermocouple > 150 °C at any mount). Refuelling with engines cold and pilot out of the suit. build
Arc core
The electrical heart. Not a reactor; a hybrid power module sized for the systems that keep the pilot alive and the suit stable.
Sources
- 5 engine starter-generators, ~2.5 kW combined at cruise.
- 1.2 kWh lithium pack (48 V, 25 Ah), 10 minutes of flight-critical load alone.
- Isolated 12 V bus for avionics from a second, smaller pack: flight computers never share a bus with the compressor.
Loads
| Flight computers + sensors | 400–600 W |
| Gimbal servos (6 axes) | 300 W avg, 1.5 kW peak |
| G-suit compressor | 400 W when pressurising |
| Cooling pump + heated layer | 150–600 W |
| Helmet, HUD, radios, telemetry | 120 W |
| Fuel pumps, ECUs | 150 W |
Policy
The controller sheds load in strict order and reports it on the HUD: convenience loads, then heated layer to minimum, then sensor duty-cycling, then gimbal rate limits. Never life support. Never flight computers. A bus fault isolates in < 5 ms with solid-state breakers.
buy components, build integrationExoframe, shell, composite metal foam
Exoframe
The engines must not hang off the pilot. A carbon-fibre and 7075-T6 aluminium frame carries boot and back thrust into a hip belt and shoulder yoke, with articulated knees and hips so the pilot can walk, kneel and climb out. Strain gauges at 24 points. Design load 6 g × 1.5 safety factor, proof-tested to 1.2 × design. Quick-release at four points for egress in < 10 s. build
Shell, Phase 1
Carbon shells over CE Level 2 impact armor (motorcycle standard) at shoulders, elbows, hips, knees, back and chest. Titanium heat shields at calves and lower back. Nomex and fire-retardant base layers. Full-coverage; no exposed skin. buy mostly
Shell, Phase 4: composite metal foam
CMF is hollow metal spheres (steel, titanium or aluminium) cast or sintered into a metal matrix. Under impact the spheres crush one by one, converting kinetic energy into plastic deformation across the panel instead of transmitting it to what is behind. Published results from the NC State program (Rabiei lab): steel-steel CMF stopped 7.62 mm armor-piercing rounds in an 18 mm-class system; absorbed 60–80% of impact energy in drop tests; survived 800 °C for 30 minutes; and attenuates X-ray, gamma and neutron radiation better than aluminium at the same mass.
What it is not: available by the sheet. Panels are made in research quantities and shaped by machining. Phase 4 is a partnership or a licence, with 12–18 months of qualification, which is why it is not on the first flight. research
| Property | Target |
|---|---|
| Panel density | ~2.5–3 g/cm³ (vs 7.8 steel) |
| Torso panel thickness | 12–16 mm |
| Energy absorbed | 60–80% of impact |
| Ballistic target | NIJ III (rifle) torso front |
| Thermal | 800 °C skin, < 40 °C inside with cooling |
| Mass, torso + helmet | 10 kg |
Sensing, compute, control
Sensors
- 3 × 9-axis IMU, triple-voted, 1 kHz.
- Head-mounted IMU: the g the pilot’s brain actually sees.
- GNSS with RTK, 10 Hz. Barometric altimeter.
- Downward radar altimeter + LIDAR, cross-checked to 10 cm below 20 m.
- 360° LIDAR puck, 77 GHz radar, stereo cameras forward, camera down.
- Pitot-static airspeed. Outside air temperature.
- Per-engine: rpm, EGT, fuel flow, vibration, mount thermocouple.
- 24 structural strain gauges. 48 shell zones in Phase 4.
Compute
- Two flight computers in lockstep (automotive-grade SoCs, ASIL-D style), hot standby switch-over < 20 ms.
- A third, minimal, hardened “reflex” processor that only knows: level the body, 1 g, descend, with no network stack. It is what EMP and software bugs fall back to.
- 1,000 Hz inner loop (attitude, rate, thrust allocation). 100 Hz outer loop (trajectory, envelope). 10 Hz supervisory layer (intent, mission, health). HQ, Hylaq’s local-first on-device intelligence research, is a candidate for this layer only.
- Deterministic RTOS for loops 1 and 2. No learned component ever has write access to the inner loop; at most it tunes parameters inside hard bounds between flights.
Flight control software (to be built)
- Envelope protection: G, onset rate, push-pull, bank, speed, altitude, descent rate, geofence. Pilot commands are clipped, not refused.
- G-LOC guard: the ladder on the overview, driven by head IMU, eye-tracker, ECG, SpO2 and input coherence.
- Thrust allocation: 6-DOF to 5 engines + 6 gimbal axes, with engine-out tables precomputed.
- Fault management: observe, classify, remediate within pre-approved actions, land for anything else.
- Auto-land: pre-surveyed sites, LIDAR confirmation, 0.5 m/s touchdown.
- Black box: every sensor, every command, 1 kHz, crash-rated, plus live telemetry to the ground.
Keeping the human alive and informed
| Biometric | Sensor | The controller acts when |
|---|---|---|
| Heart rate and rhythm | Chest ECG strap | > 180 bpm, arrhythmia, or rate falling under rising G (vasovagal) |
| Oxygen saturation | Earlobe pulse-ox | < 90% warn · < 85% descend |
| Consciousness | Visor eye-tracker: fixation, pupil, blink | Fixation loss > 1 s under load, pupil lag → unload |
| Head G | Helmet IMU | Drives the G-LOC ladder, not the frame IMU |
| Core temperature | Ingestible pill or tympanic | 38.5 °C warn · 39.0 °C land |
| Breathing / AGSM | Chest strain band | No strain cycles above 4 g → cue, then soften |
| Helmet air | CO, CO2, O2 sensors | CO 25 warn · 50 abort |
| Posture and input | Head IMU, grip sensors | Head slump or limp grips → incapacitation protocol |
Life support hardware
- G-suit: 5 bladders (calves, thighs, abdomen), 70 kPa, compressor + accumulator for 200 ms fill. buy
- Liquid cooling garment, 350 W removal, radiator in the dorsal airflow. buy
- Oxygen: 2 L composite cylinder, demand regulator, 30 min. buy
- Heated gloves, socks, base layer. Sealed heated visor with anti-fog. buy
- Airbags: neck, hips, knees; 80 ms; fired by the controller on fall detection or ABORT below 3 m. build
Pilot interface
- Twist-grip throttle on each hand thruster; The controller blends them. Big guarded ABORT on both grips and on the ground controller.
- HUD: horizon, altitude, airspeed, G with ladder colour, fuel minutes, vitals, geofence, controller intent (“unloading”, “landing”). Red means act now.
- Audio by bone conduction: AGSM metronome, callouts, ground crew.
- Haptics: shoulder tap on the side the controller is about to turn toward.
Test infrastructure
Tether gantry
Overhead gantry with a load-cell tether, 6 m travel, fall-arrest to 1.5 m. Every hover hour before free flight happens here. build · ~$25k
Pad
Paved, 20 m clear radius, foam pit 6 × 6 m for first free hovers, wind station, downwind exhaust area, fuel store 15 m away. Fire crew with foam and a medic at every engine run.
Ground station
Telemetry at 50 Hz over 900 MHz + LTE, live vitals, remote ABORT, controller health view, video. Every flight recorded and reviewed before the next.
Hardware-in-the-loop sim
Flight computers running against a physics model with engine lag, sensor noise and injected failures. 500 simulated engine-outs before the first real one.
Centrifuge access
Rent time at a human centrifuge facility for pilot qualification and to validate the G-LOC ladder against a real human.
Engine test stand
Single-engine thrust stand with fuel-flow and EGT logging. Characterise every engine before it goes on a body.