Browser-based hardware-in-the-loop simulation against real 400 Hz quadrotor physics. Tune PIDs, test failsafes, and watch the telemetry — no broken props.
CalculatorsCalculators
Free engineering calculators for every part of the build
Component DatabaseComponent Database
Real specs for motors, ESCs, flight controllers and more
Build GuidesBuild Guides
Step-by-step guides from first quad to advanced tuning
Thrust-to-Weight
Calculate T/W ratio for your build
Flight Time
Battery, weight & current-draw model
Motor / Prop Matching
KV + voltage to prop size & efficiency
Battery Sizing
Match battery to power requirements
ESC Sizing
Size ESC from motor + battery specs
RF Link Budget
Full link budget for control & video
Antenna Calculator
Antenna gain, range & Fresnel zone
propulsionDrone Propulsion System Design: The Complete Guide
Comprehensive guide to designing a drone propulsion system — motor physics, propeller aerodynamics, thrust-to-weight targets, efficiency optimization, and advanced topics.
flight controllersBest Flight Controllers for Drones — 2026 Buyer's Guide
A comprehensive buyer's guide to the best flight controllers in 2026 — by category, use case, and budget — with spec comparisons and firmware compatibility notes.
powerLiPo Battery Guide for Drone Builders
Everything you need to know about LiPo batteries: chemistry, cell count, C-rating, capacity, and safe charging.
Free engineering tools. Open and honest specs. No fluff, no paywalls.