A clearer App Store name and search details. No other changes in this update.

Flight Envelope Explore how changes in empty mass and drag affect the modeled flight of the same rocket and motor. 1. Configure a rocket, motor and conditions in Altitude. 2. Open Flight Envelope and choose mass and drag variations. 3. Run the sensitivity check, inspect the scenarios and share the report. This is a model sensitivity study, not a probability interval or permission to launch. Only empty mass and drag vary. Wind, motor variation, instability and other conditions can produce results outside the displayed range. Scenario inputs are a snapshot; return to Altitude to change the baseline.

New Two-Stage & Cluster Planner: simulate a booster + sustainer flight or a multi-motor cluster - staging altitude and speed, total apogee, and the right sustainer delay to fly. New Flight Duration Planner predicts your total flight time from liftoff to landing and sizes the chute to hit a contest duration window. Plus, share any rocket design as a file and import designs from teammates - perfect for clubs and student teams, no account needed.

Version 2.1 • New Launch Readiness Card: combines altitude simulation, ejection delay, rod-exit speed, Barrowman stability, recovery drift, wind, and field size into a single go/caution/hold field checklist. • New Offline Field Card Deck: bundled launch-day reference cards for common model-rocketry checks, designed to work when the field has no signal. • Fixed the shared New Rocket action in Altitude, Stability, and Recovery. It is now a full-width command row with an immediate visible draft rocket, reset fields, and confirmation on iPad. • Refreshed App Store screenshots and metadata to show the current 2.1 interface and tools. Estimates assume near-vertical flight and approximate published specs — always confirm against the certified data on the motor and follow the safety code.

This update sharpens the interface: the iPad layout now uses a centered, comfortable reading width instead of stretching edge to edge, so every screen reads as a clean column. iPhone is unchanged; still fully on-device.

Apexline 2.0 — a pro upgrade for the launch pad, still 100% offline. • Fin Flutter Analysis: the #1 cause of lost fins on fast flights, with a "thicken fins to X mm" margin solver. • Wind & Launch Angle: weathercock tilt, apogee lost to wind, ground track, and total landing distance, plus a recommended rod angle. • Dual Deployment: drogue + main sizing, both descent phases, and how much drift it saves over a single main. • Target-Altitude Ballast Solver: the exact nose ballast to hit an apogee on a chosen motor. • Motor Insight: specific impulse, position-in-class, and per-delay NAR ±10% tolerance windows. Plus the same RK4 trajectory sim and Barrowman stability. No account, no network — all the physics runs on your device.

Introducing a real, impulse-conserving thrust-curve engine — Apexline now models each motor spike-and-tail thrust over time (shown as a chart on Altitude and every motor), and recovery now accounts for the spent casing in landing mass. Plus a deploy-before-apogee check, a transonic honesty note, and a full accessibility pass.

Version 1.2 • Motor Compare — the most-requested workflow improvement. Tap the arrows icon in the Motors tab to open the new Motor Compare screen. Select up to 8 motors from the full catalog and Apexline runs the complete flight simulation for each one against your current rocket in one pass. Results are ranked in a table with apogee, thrust-to-weight, rod-exit verdict, optimum delay, and the best-matching available delay for each motor. Sort by any column. An optional bar chart shows the apogee spread at a glance. No more switching motors one at a time on the Altitude tab. • Flight Stats — tap the chart icon in the Flight Log toolbar to see a summary of your prediction accuracy across all flights with altimeter readings: mean error, mean absolute error percentage, a verdict on calibration quality, and a flight-by-flight error trend chart. Colour-coded dots show which flights were within 10 %, which were off, and whether accuracy is improving over time. • Two new Learn guides — "Comparing motors side by side" (how to get the most from Motor Compare) and "Reading your flight statistics" (how to interpret the error trend and use Cd calibration to close the gap).

Version 1.1 • Flight Log — record your actual flights with the motor used, measured apogee, notes, and launch site. Compare your altimeter reading against the simulation's prediction and see a running error percentage so you know how well your Cd estimate tracks reality. Export all entries as a CSV file. • Cd Calibration — enter a measured apogee and Apexline back-calculates the exact drag coefficient that would have produced it, then lets you apply it to your rocket profile with one tap. • Field & Safety Calculator — enter your motor class and field size to check the NAR minimum field requirement. Separate drift calculator shows how much field you need to contain the rocket at your deployment altitude, descent rate, and wind speed. Wind-limit checker shows the maximum safe wind for your rod-exit speed. • Expanded motor catalog — added Apogee Components motors (A7, B6, C10, D3, E6) and additional AeroTech composite motors (F39, G25, G40, H45, H73, I161, J180). • Log Flight shortcut — after any altitude simulation, a "Log this flight" button pre-fills the motor and predicted apogee so recording a flight takes seconds.