Apexline

iOS app by Shadowfetch · App Store ID 6777868815 · iOS

Apexline is the offline flight computer for model rocketry. Whether you fly Estes kits with the kids, chase a target altitude for a contest, or build your own designs, Apexline answers the questions that matter on the launch field — how high will it go, which ejection delay should I use, will it fly straight, what chute do I need, and is this launch-day setup inside a safer planning range — all without an account, ads, or an internet connection.

How High Will It Go?

Enter your rocket's mass, diameter, and drag, pick a motor, and Apexline simulates the whole flight — boost, coast, and the climb to apogee. It reports your predicted altitude, time to apogee, maximum speed and acceleration, burnout altitude, and the speed coming off the launch rod, plus a clean altitude-vs-time graph. Launch-site altitude and air temperature are factored in, because thinner air flies higher.

Which Delay? (The Most Common Mistake)

Deploy too early and the parachute shreds; too late and the rocket nose-dives. Apexline calculates the optimum ejection delay — the exact coast time to apogee — then tells you which of your motor's available delays is closest. For a typical Estes Alpha on a C6, it recommends the C6-5, just like the catalog.

Will It Fly Straight?

Apexline finds your rocket's center of pressure with the Barrowman equations (the same method desktop simulators use) from your nose and fin geometry. Enter the balance point and it shows the static margin in calibers with a clear verdict — unstable, marginal, stable, or overstable — and a live diagram of CP and CG so you can see the margin before you fly.

Pick The Right Motor

Browse a built-in catalog of common Estes, Quest, AeroTech and Klima motors, organized by impulse class, with total impulse, thrust, burn time, available delays, and masses. Not sure what "C6-5" means? The decoder spells out the class, the average thrust, and the delay from any motor code you type.

Privacy and support

Privacy information for Apexline · Support for Apexline

Questions: shadowfetchapps@gmail.com

Apexline · App Store ID 6777868815 · Published by Shadowfetch · shadowfetch.com