Rotor disk loading
API · /drone-api
Drone Build API
healthy
4,319 Subscribers
Multirotor (drone) flight maths as an API, computed locally and deterministically — the thrust, efficiency and hover numbers an FPV builder or UAV designer dials a quadcopter in with. The thrust-weight endpoint gives the thrust-to-weight ratio, total motor thrust ÷ all-up weight: aim for at least 2:1 so the craft has authority to hold position and fight wind, with freestyle wanting 3–5:1 and heavy-lift living near 1.5:1 — four 800-gram motors on a 1,200-gram quad is a punchy 2.67:1. The disk-loading endpoint gives the rotor disk loading, weight ÷ total prop disk area, where lower is more efficient: big slow props move more air for less power, which is why endurance and cinematic rigs run large props at low disk loading. The hover-throttle endpoint gives the hover throttle, all-up weight ÷ total thrust — a good build hovers near 40–50 % leaving headroom for manoeuvres, while hovering above ~60 % means it is overweight, sluggish and runs hot. Everything is computed locally and deterministically, so it is instant and private. Ideal for FPV and drone-build apps, UAV-design and motor-selection tools, hobbyist calculators, and maker sites. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 compute endpoints. Estimates — bench-test motors at your voltage and prop. For battery runtime use a battery API.
api.oanor.com/drone-api
API health
healthy- Uptime
- 100.00%
- Server probes · 24h
- Avg latency
- 84 ms
- Server probes · 24h
- Subscribers
- 4,319
- active
- Total calls
- 4
- last 7 days
Pricing
Pick a tier — billed monthly, cancel anytime.
Free
Free
- 750 calls / month
- 2 requests / second
- Hard cap (429 above quota, no overage)
- 750 calls/month
- 2 req/sec
- TWR + disk loading + hover
- No credit card
Starter
€4.45 /month
- 18,000 calls / month
- 8 requests / second
- Hard cap (429 above quota, no overage)
- 18,000 calls/month
- 8 req/sec
- Build-spec calculations
- Email support
Pro
€15.30 /month
- 105,000 calls / month
- 20 requests / second
- Hard cap (429 above quota, no overage)
- 105,000 calls/month
- 20 req/sec
- Build-app & shop pipelines
- Priority support
Mega
€47.00 /month
- 360,000 calls / month
- 48 requests / second
- Hard cap (429 above quota, no overage)
- 360,000 calls/month
- 48 req/sec
- Platform scale
- Dedicated SLA
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Related APIs
Other APIs with overlapping tags.
RC Servo & PWM API
RC servo and PWM maths as an API, computed locally and deterministically — the pulse-width, angle and duty-cycle numbers a robotics, RC or embedded developer drives a servo with. The angle endpoint turns a pulse width into the servo angle: a hobby servo reads the width of the pulse (not a duty cycle), so the standard 1000–2000 µs maps linearly across the travel with 1500 µs at centre — angle = (pulse − min) ÷ the min-to-max span × the travel — and it flags when a pulse asks for more than the configured range so you do not drive the servo into its mechanical stops. The pulse endpoint runs it the other way, giving the pulse width a microcontroller should write for a target angle (90° is 1500 µs on a 1000–2000 µs / 180° servo), exactly what an Arduino-style servo library computes under the hood. The duty endpoint converts a pulse and a refresh frequency into the PWM period and duty cycle: a 50 Hz servo frame is 20 ms, so a 1500 µs pulse is just 7.5 % duty — the value a timer peripheral needs — and faster frames for digital servos or multirotor ESCs (e.g. 333 Hz) change it. Everything is computed locally and deterministically, so it is instant and private. Ideal for robotics and RC firmware, microcontroller and embedded tools, drone and animatronics projects, and maker calculators. Pure local computation — no key, no third-party service, instant. 3 compute endpoints. For stepper steps-per-mm use a stepper-motor API.
api.oanor.com/servo-api
Worm Gear API
Worm-gear engineering maths as an API, computed locally and deterministically — the ratio, lead-angle and efficiency numbers a machine designer or millwright sizes a worm drive with. The ratio endpoint gives the reduction = wheel teeth ÷ worm starts, so a single-start worm on a 40-tooth wheel is a big 40:1 reduction in one compact stage — the high ratio in a small package is the whole appeal of a worm drive. The geometry endpoint gives the lead (= starts × axial pitch, with axial pitch = π × module) and the lead angle = atan(lead ÷ (π × worm pitch diameter)), and tests for self-locking: a small lead angle (roughly under 5–6° for typical steel-on-bronze) means the wheel cannot back-drive the worm — invaluable for hoists and holding loads, at the cost of efficiency. The efficiency endpoint gives the mesh efficiency when the worm drives = tan(lead angle) ÷ tan(lead angle + friction angle), which is low for the small lead angles that give big ratios — often 50–70 %, which is why worm gears run warm and need good lubrication — while high-lead multi-start worms reach 90 %+; when the lead angle drops to the friction angle the drive becomes self-locking. Everything is computed locally and deterministically, so it is instant and private. Ideal for mechanical-design and gearbox tools, machine-building and CAD utilities, and engineering calculators. Pure local computation — no key, no third-party service, instant. Confirm self-locking dynamically — vibration can unlock a marginal pair. 3 compute endpoints. For spur gears use a spur-gear API; for a general ratio a gear-ratio API.
api.oanor.com/wormgear-api
Air-Fuel Ratio API
Air-fuel ratio and lambda maths for engine tuning as an API, computed locally and deterministically — the lambda, AFR and mixture numbers a tuner, ECU developer or motorsport engineer dials fuelling in with. The lambda endpoint turns a measured air-fuel ratio into lambda (the AFR divided by the fuel's stoichiometric AFR — 14.7 for gasoline) and the equivalence ratio φ = 1/lambda, classifying the mix as rich, stoichiometric or lean: a gasoline AFR of 13.0 is lambda 0.88, an 11.6 % rich mixture, the sort used at wide-open throttle for power and a cooler, safer burn. The afr endpoint runs it the other way — pick a target lambda and it gives the AFR the wideband should read — and because the AFR number is fuel-specific (E85's stoichiometric AFR is about 9.8, not 14.7) it always works from the right fuel, which is why pros tune in lambda when switching fuels. The mixture endpoint links the air the engine breathes to the fuel the injectors must add: give an air mass and a target lambda and it returns the fuel mass (or vice-versa), the heart of how an ECU sizes fuelling from measured airflow. Built-in stoichiometric ratios for gasoline, E10, E85, ethanol, methanol, diesel, LPG, propane, methane/CNG and hydrogen, or pass your own. Everything is computed locally and deterministically, so it is instant and private. Ideal for engine-tuning and dyno tools, ECU and standalone-management apps, motorsport and data-logging utilities. Pure local computation — no key, no third-party service, instant. 3 compute endpoints. For engine displacement and power use an engine API; for chemical reaction stoichiometry a stoichiometry API.
api.oanor.com/airfuel-api
Sonar & Underwater Sound API
Underwater-sound and sonar maths as an API, computed locally and deterministically — the speed, absorption and ranging numbers a marine engineer, sonar developer or oceanographer works with. The sound-speed endpoint gives the speed of sound in seawater from the Mackenzie nine-term equation: about 1,500 m/s — far faster than in air — rising with temperature, salinity and depth, so a profile of 25 °C, 35 ppt at 1,000 m gives 1,550.7 m/s. Because the speed varies with depth, sound rays bend and form the SOFAR channel that carries whale song and signals across whole oceans. The absorption endpoint gives Thorp's sound-absorption coefficient in dB per km against frequency, with the loss over a path: seawater swallows high frequencies fast, which is why long-range sonar and whale calls are low-pitched while high-frequency sonar gives sharp images only at short range. The echo-range endpoint turns an echo sounder's or sonar's two-way travel time into the range or depth — distance = sound speed × time ÷ 2 — so a one-second round trip at 1,500 m/s is a target 750 m away, its accuracy resting on the assumed sound speed. Everything is computed locally and deterministically, so it is instant and private. Ideal for sonar and hydrophone tools, marine-survey and bathymetry apps, ocean-acoustics research, and AUV/ROV navigation utilities. Pure local computation — no key, no third-party service, instant. Standard-equation estimates over their valid ranges. 3 compute endpoints. For the speed of sound in air and Mach use a Mach-number API; for decibels a sound-level API.
api.oanor.com/sonar-api
Frequently asked questions
Quick answers about pricing, quotas, and integration.
How do I get an API key for Drone Build API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Drone Build API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Drone Build API?
Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.
How much does Drone Build API cost?
Drone Build API has a free tier with 100 calls / month. Paid plans start at €4.45 / month with higher quotas and faster rate limits.
Can I cancel my subscription anytime?
Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.
Is Drone Build API GDPR-compliant?
All requests to Drone Build API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.
Pick an endpoint from the list on the left to see its details and try it.
Code snippets
Sign up to get an API key, then call any path under your slug.
curl https://api.oanor.com/drone-api/SOME_PATH \
-H "x-oanor-key: oanor_test_..."const res = await fetch("https://api.oanor.com/drone-api/SOME_PATH", {
headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();$ch = curl_init("https://api.oanor.com/drone-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);import requests
r = requests.get(
"https://api.oanor.com/drone-api/SOME_PATH",
headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())Ratings
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