Support
ApogeeLog — Model Rocketry field companion
Getting Started
How do I predict my apogee?
Open the Predict tab, pick a rocket from your fleet (or add one with its mass, diameter, and drag), and choose a motor from the bundled certified-motor database. ApogeeLog runs a deterministic boost-and-coast simulation and shows your predicted apogee and max velocity, with altitude-vs-time and velocity-vs-time charts. Every result is shown with a visible ± error band.
What does the error band mean — how accurate is it?
Apogee prediction is an estimate, not a measurement. ApogeeLog uses the same physics the desktop tools use, so the predicted number lands in roughly the same ~10–15% band — that's what the error band represents. Real altitude depends on wind, build, motor lot, and launch angle. We deliberately never claim "pinpoint" accuracy; always verify altitude with a certified altimeter for official records.
Why doesn't ApogeeLog claim to be more accurate than OpenRocket?
Because it isn't — and that's the point. ApogeeLog uses the same well-trusted boost-and-coast math. Where it wins is running that math reliably in your pocket at the launch field, fully offline, alongside recovery sizing and a real logbook. We compete on reliability, offline field-use, and the log, not on an accuracy claim.
Recovery & Motors
How does parachute sizing work?
Enter a target descent rate and ApogeeLog solves for the parachute diameter — or enter a chute you own and get the resulting rate. It supports flat and dome presets, checks against a 3–6 m/s safe band, estimates wind drift, and can refine for density altitude using your field elevation and temperature. All of it is a planning estimate, not a guarantee.
What's in the certified motor database?
A searchable snapshot built on the public NAR/Tripoli/CAR certified lists, with each motor's total impulse, average thrust, burn time, and thrust curve. Search by designation, class, or manufacturer. The snapshot is bundled in the app, so it works with zero signal.
Is the motor database offline? How current is it?
Yes — the bundled snapshot works fully offline and shows a "motor data as of <date>" label. Premium subscribers can optionally refresh it from the public ThrustCurve.org data when they have a connection. The refresh sends only the motor query, never any personal data.
Flight Log & Cert Proof
How do I log a flight?
From a prediction, tap to save it as a flight, then add what actually happened — the measured apogee from your altimeter, the motor used, and an optional GPS landing site. The log keeps predicted vs measured side by side, plus live stats like your highest and fastest flight, total impulse, cert progress, and most-flown rocket.
What is the cert proof report?
A one-tap, one-page PDF (plus CSV) for cert paperwork and club files. It includes the rocket and motor spec, the altitude curve, the recovery plan, and a log summary — with the assumptions and the error band printed on the page. It is a self-reported record for paperwork, not a certifying measurement.
Ground Altitude Tracker
Is the Altitude Tracker an altimeter?
No. The tracker is a no-hardware estimate: you aim your phone at the rocket at apogee, and it uses the device's elevation angle and a known baseline distance to estimate altitude, shown with an uncertainty band. It's a practice-flight tool — handy so you don't risk losing an expensive onboard altimeter to drift — but it does not replace a certified onboard altimeter for official records.
What is two-station tracking?
With Premium, two observers at a known baseline each take an angle on the rocket. ApogeeLog combines them and reports the NAR 10% "track closed" confidence, the same closure check used in optical tracking. Single-station tracking is available free.
Free vs Premium
What's free vs Premium?
Free forever: unlimited apogee prediction and recovery sizing with the full bundled motor database, the single-station altitude tracker, and up to 3 saved rockets and 10 logged flights. Premium: unlimited flight & motor log and full fleet, ongoing motor-database refresh, the cert proof report (PDF + CSV), two-station altitude tracking, and advanced calculations (stability, ejection charge, drift, optimal delay, density altitude).
Is there a free trial?
Yes — the Premium Annual plan ($19.99/year) includes a 7-day free trial. You'll only be charged at the end of the trial. Cancel anytime in your Apple ID subscription settings before the trial ends.
How do I restore my purchase?
Open Settings inside the App and tap "Restore Purchases". This re-applies your active subscription if you've previously purchased one on this Apple ID.
How do I cancel my subscription?
Open the iOS Settings app, tap your name at the top, then tap Subscriptions. Find ApogeeLog and tap Cancel Subscription. Cancellation takes effect at the end of the current billing period.
Privacy & Offline
Does it need an internet connection?
No. Apogee prediction, recovery sizing, the altitude tracker, the logbook, and report export all run entirely on your device — even on a plane or at a field with no signal. The only optional network use is the Premium motor-database refresh.
Where does my data go?
It stays on your iPhone. There's no account and no sign-in, and ApogeeLog has no servers that hold your rockets, flights, or reports. Our App Store privacy label is Data Not Collected. See the Privacy Policy for details.
What permissions does the app need?
Only optional Location (When In Use), used solely if you choose to tag a flight's landing site or refine for your field elevation — it's stored locally and never transmitted. The Altitude Tracker reads your device's orientation sensors on-device. No camera, microphone, contacts, or photo-library access.
Contact Us
Email Support
For questions, bug reports, or feature requests:
We typically respond within 48 hours. If you're reporting a prediction that seemed off, sending the rocket and motor you used (and the measured apogee, if you have it) helps us reproduce.