A free browser-based hardware-in-the-loop flight simulator, engineering calculators, an honest component database, and real build guides.
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
Browser-based hardware-in-the-loop simulation running your actual PX4 firmware at 400 Hz. Tune PIDs, test failsafes, and validate builds — no broken props.
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.
