ThrustLine Rocket Lab

ThrustLine Rocket Lab is an offline-first design, simulation and range-day workbench for model rocketeers, STEM and physics teachers, scout and youth-group leaders, university rocket-club beginners, and parents launching with kids for the first time. It answers the three questions that decide a launch: Is my rocket stable? How high will it go? Is today a go? Everything runs on your device — no accounts, no ads, no analytics — and results are labelled as hobby-planning approximations. The app contains no propellant formulation content and makes no performance or safety guarantees. DESIGN BENCH Assemble nose profile, body tube, fin set, motor mount and recovery hardware with a live gram-by-gram mass roll-up. A seeded component library includes BT-50/BT-60 tubes, balsa and ply fins, engine hooks, wadding and chute sizes. STABILITY LAB See center of gravity from component masses and a simplified Barrowman-style center of pressure for nose and fin set, drawn as CG/CP markers on a scaled rocket side view. Get a caliber-margin verdict with plain-language fixes: add nose weight, use larger fins, or lengthen the tube. FLIGHT SIMULATOR A 1D vertical integration of thrust minus gravity minus velocity-squared drag produces stacked altitude, velocity and acceleration charts. Read apogee, max velocity, rail-exit speed and a recommended ejection delay band. MOTOR LIBRARY Seeded generic A–G class motor templates (total impulse, average and peak thrust, burn time, delay choices) can be cloned, edited and saved, with per-rocket compatibility flags. RECOVERY DESK Size parachutes to a target descent rate, compare streamer versus chute, and estimate wind-drift landing with a footprint ellipse over a scale ground grid. Includes shock-cord and wadding guidance. RANGE DAY CONSOLE Enter wind speed, gust spread, temperature and cloud ceiling manually to get a go/no-go verdict with every threshold visible. Run pad-setup, countdown-script and misfire-procedure cards, plus a four-stage checklist (prep, pad, launch, recovery) with timestamps, skip-with-reason and per-launch receipts. FLIGHT DEBRIEF Record measured apogee, delay outcome, drift distance, damage notes and photos per flight. Compare predicted versus measured deltas and browse a sortable launch-history table for each rocket. EXTRAS Export a one-page PDF spec sheet per rocket (mass table, stability verdict, simulation summary, recovery setup, checklist) via the system share sheet. Read an offline Primer Library with original in-house articles on stability margin, delay selection, fin alignment, ejection charge sizing, launch-site etiquette and safety-code summary. Opt in to launch-day reminders, add a Glance home-screen widget showing the next launch countdown with rocket, motor and go/no-go state, and open in-app Privacy Policy and Terms. Nine screens ship cold-start ready: Rockets vault, Design Bench, Stability Lab, Simulator, Motor Library, Recovery Desk, Range Day Console, Flight Debrief, Primer + Settings. Designed for classroom and club use, with nothing leaving your device.