# Glide Ratio API
> Aircraft glide-performance maths as an API, computed locally and deterministically — the glide-distance, glide-ratio and reachability numbers a pilot, flight-instructor or flight-sim developer works an engine-out or soaring problem with. The glide-distance endpoint gives the still-air distance you can cover = height above the ground × the glide ratio (L/D): from 5,000 ft at a 9:1 ratio you reach about 45,000 ft, ~7.4 nm, with the answer in feet, nautical miles and kilometres. The glide-ratio endpoint reads the slope straight off the polar — glide ratio = forward speed ÷ sink rate (1 knot ≈ 101.27 ft/min), so 60 kt at a 600 ft/min sink is about 10:1, a 5.6° glide path — and gliders reach 40–60:1, a light single ~9:1, an airliner ~17:1. The reach endpoint answers the practical question: the height needed to reach a field = distance ÷ glide ratio, the arrival height is what is left, and it only counts as making it if that clears a safety reserve (default 1,000 ft) for the circuit and approach. Everything is computed locally and deterministically, so it is instant and private. Ideal for flight-planning and EFB apps, gliding and soaring tools, flight-simulator and training utilities, and aviation-safety calculators. Pure local computation — no key, no third-party service, instant. Still-air estimates — adjust for wind, configuration and a margin. 3 compute endpoints. For density altitude use a density-altitude API; for runway wind components a crosswind API.

## Authentication
All requests require your oanor API key in the `x-oanor-key` header. Get one at https://www.oanor.com/developer/keys.

```bash
curl -H "x-oanor-key: oanor_live_…" "https://api.oanor.com/glideratio-api/..."
```

## Pricing
- **Free** (Free) — 6,100 calls/Mo, 2 req/s
- **Starter** ($11/Mo) — 63,000 calls/Mo, 6 req/s
- **Pro** ($33/Mo) — 265,000 calls/Mo, 15 req/s
- **Mega** ($101/Mo) — 1,350,000 calls/Mo, 40 req/s

## Endpoints

### Glide

#### `GET /v1/glide-distance` — Glide distance from height and ratio

**Parameters:**
- `height_ft` (query, required, string) — Height above landing point (ft) Example: `5000`
- `glide_ratio` (query, required, string) — Glide ratio (L/D) Example: `9`

**Example:**
```bash
curl -H "x-oanor-key: $KEY" \
  "https://api.oanor.com/glideratio-api/v1/glide-distance?height_ft=5000&glide_ratio=9"
```

#### `GET /v1/glide-ratio` — Glide ratio from airspeed and sink

**Parameters:**
- `airspeed_kt` (query, required, string) — Airspeed (knots) Example: `60`
- `sink_rate_fpm` (query, required, string) — Sink rate (ft/min) Example: `600`

**Example:**
```bash
curl -H "x-oanor-key: $KEY" \
  "https://api.oanor.com/glideratio-api/v1/glide-ratio?airspeed_kt=60&sink_rate_fpm=600"
```

#### `GET /v1/reach` — Airfield reachability

**Parameters:**
- `height_ft` (query, required, string) — Current height (ft) Example: `5000`
- `glide_ratio` (query, required, string) — Glide ratio (L/D) Example: `9`
- `distance_nm` (query, required, string) — Distance to field (nm) Example: `5`
- `safety_height_ft` (query, optional, string) — Safety reserve (ft, default 1000) Example: `1000`

**Example:**
```bash
curl -H "x-oanor-key: $KEY" \
  "https://api.oanor.com/glideratio-api/v1/reach?height_ft=5000&glide_ratio=9&distance_nm=5&safety_height_ft=1000"
```

### Meta

#### `GET /v1/meta` — Spec

**Example:**
```bash
curl -H "x-oanor-key: $KEY" \
  "https://api.oanor.com/glideratio-api/v1/meta"
```


---
Marketplace page: https://www.oanor.com/api/glideratio-api
OpenAPI spec: https://www.oanor.com/api/glideratio-api/openapi.json