# SC-17 CAREWING

## Reference aircraft configuration for the Simplycity Amsterdam care corridor

**Revision 0.1 · 21 September 2026 · Concept / pre-feasibility**

> SC-17 is a reference aircraft, not a claimed Simplycity product or an airworthy design. It gives the care-corridor pilot a concrete vehicle envelope for routing, hubs, noise, safety and service design. Every value is a preliminary sizing estimate and must be validated by the selected design organisation, operator and competent authority before procurement, manufacture or flight.

## The pitch

**SC-17 CAREWING turns a 17-minute hospital sample corridor into a quiet, traceable electric service: vertical at the roof, wing-borne between care sites, and visible to every stakeholder through Simplycity.**

Simplycity remains the coordination layer, not a drone manufacturer. This is the reference configuration that makes the first service tangible and lets the city design a disciplined operating envelope.

## Architecture

SC-17 is a **battery-electric quadplane**: four dedicated vertical-lift rotors handle approved rooftop departures and arrivals; a fixed wing and rear pusher propeller complete the cross-city leg. The combination avoids a hover-only multicopter’s cruise-energy penalty while keeping a compact pad footprint.

| Choice | Rationale |
|---|---|
| Four independent lift rotors | Controlled vertical launch/landing; failure tolerance requires later demonstration. |
| High wing + rear pusher | Efficient wing-borne cruise; clean cargo access and propeller separation. |
| Removable 7 L cassette | 2.5 kg samples, custody scan, temperature logging and fast turnaround. |
| 0.42 kWh swappable battery | Reference mission plus reserve; supports short hub dwell. |
| Fixed care corridor | Turns route, noise, weather minima and contingency sites into measurable evidence. |

## Reference specification

| Item | Preliminary value |
|---|---:|
| Configuration | Electric quadplane; fixed wing; rear pusher; V-tail |
| Payload | 2.5 kg maximum; 7 L insulated cassette target |
| MTOM | 13.6 kg target envelope |
| Span / length / height | 1.75 m / 1.18 m / 0.42 m |
| Wing area / aspect ratio | 0.42 m² / 7.3 |
| Lift system | 4 × 457 mm (18 in) rotors |
| Battery | 0.42 kWh nominal, 80% usable planning assumption |
| Cruise | 95 km/h (26.4 m/s) nominal |
| Stall estimate | 61 km/h (17.0 m/s), clean; test required |
| Nominal range | 35 km, still-air planning envelope |

## 17-minute corridor model

**Scenario:** 18 km direct route between hospital rooftop micro-hubs.

| Segment | Time | Aircraft energy |
|---|---:|---:|
| Authenticate, load, pre-flight release | 1.5 min | Hub power |
| Vertical departure + transition | 0.67 min | 2.5 kW model |
| Wing-borne cruise, 18 km at 26.4 m/s | 11.36 min | 0.47 kW model |
| Transition + vertical landing | 0.67 min | 2.5 kW model |
| Receive, scan and handover | 2.8 min | Hub power |
| **Door-to-door target** | **17.0 min** | **0.170 kWh nominal aircraft mission** |

Flow checks aircraft health, weather, route and airspace before release. The aircraft climbs from a controlled pad, transitions to wing-borne cruise within an approved route volume, then lands at the receiving hub. Trust provides the authorised shared operating picture and audit trail; Impact records service, energy and measured noise. Out-of-envelope missions do not launch or divert according to an approved policy.

## First-order sizing calculations

### Mass and wing loading

Assumed worst-case weight: `W = 13.6 kg × 9.81 = 133.4 N`.

`W/S = 133.4 N / 0.42 m² = 318 N/m²` (32.4 kg/m²).

Preliminary budget: structure/fuselage 3.0 kg; wing/tail 0.9 kg; lift units 1.9 kg; cruise propulsion 0.5 kg; battery 2.0 kg; avionics/cargo interface 0.6 kg; payload 2.5 kg; allowance 2.2 kg = **13.6 kg MTOM**. This is a target, not a substantiated mass statement.

### Stall check

For sea-level `ρ = 1.225 kg/m³`, wing `S = 0.42 m²` and provisional `CLmax = 1.8`:

`Vs = √[2W / (ρ S CLmax)] = √[2 × 133.4 / (1.225 × 0.42 × 1.8)] = 16.97 m/s = 61.1 km/h`.

The 95 km/h cruise point is `1.55 × Vs`. Actual airfoil, gust margin and CLmax require wind-tunnel and flight validation.

### Cruise drag and power

At `V = 26.4 m/s`, use preliminary polar `CD = CD0 + k CL²`; `CD0 = 0.040`; `AR = 7.3`; `e = 0.75`; `k = 1/(πAR e) = 0.058`.

`CL = W / (0.5 ρ V² S) = 0.744`.

`CD = 0.040 + 0.058 × 0.744² = 0.072`.

`D = 0.5 ρ V² S CD = 12.9 N`.

At 70% propulsive efficiency, `P = D V / 0.70 = 486 W`; planning cruise electrical draw is **0.47–0.55 kW**. Bench-tested motor, ESC, propeller and installation losses will replace this estimate.

### Vertical-lift power

Four 457 mm rotors yield `A = 4π(0.457/2)² = 0.656 m²`.

`Pi = √[W³/(2ρA)] = 1.21 kW` ideal induced power.

At provisional 0.65 figure of merit: `1.21/0.65 = 1.86 kW`; allowing profile, drivetrain and control margin gives **2.5 kW planning hover draw**. Installed peak power, thermal performance and one-motor-out behaviour are unproven until testing.

### Energy and reserve

Cruise: `0.47 kW × (18,000/26.4) s / 3600 = 0.089 kWh`.

Vertical/transition: `2.5 kW × 80 s / 3600 = 0.056 kWh`.

Avionics/payload thermal allowance: `0.025 kWh`. Nominal total: **0.170 kWh**. A 30% contingency reserve adds `0.051 kWh`, so planning requirement is **0.221 kWh**.

A 0.42 kWh pack at 80% usable capacity provides `0.336 kWh` usable, or `0.115 kWh` additional margin. At 0.50 kW planning cruise, a 30% operational derate produces the **35 km nominal range envelope**. This is not a guaranteed range: dispatch must account for wind, diversion, ageing and weather.

## Safety concept and verification

1. Before launch: independent positioning, geofence, weather/UTM checks, health check, cassette identity and temperature check.
2. In flight: autopilot plus independent health monitor, primary communications and contingency link, loss-link behaviour, energy/wind monitoring and route-volume containment.
3. Degraded policy: reject launch, return, continue only where energy policy allows, or divert to a surveyed contingency site.
4. Ground safety: locked pad during rotor operation, personnel exclusion zone, positive cassette retention and battery thermal monitoring.

| Gate | Evidence needed |
|---|---|
| G0 — route | Care workflow, survey, stakeholder agreement, contingency inventory. |
| G1 — model | Mass properties, propulsion map, aero/rotor/noise model and initial risk assessment. |
| G2 — ground | Structural, battery thermal, EMC, cargo and containment evidence. |
| G3 — flight development | Hover/transition, failure behaviours and measured acoustics. |
| G4 — supervised corridor | Approved demonstrations, operational weather/energy data and custody evidence. |
| G5 — limited service | Accepted safety case, maintenance, training and public-value review. |

## Package index

- `SC17-Carewing-Blueprint.pdf` — portable continuity briefing
- `sc17-design-book.html` — image-rich printable book
- `sc17-blueprint.svg` — editable three-view concept
- `sc17-studio-render.png` — original studio render
- `sc17-route-render.png` — original operational render

**Important:** This package is an engineering concept only; it is not a manufacturing drawing, flight manual, safety case or approval to operate.