Home - Apex Rocket Simulator

High Power Rocketry · Flight Simulation

Simulate your rocket.

Before you fly it.

Project APEX is a professional-grade flight simulator for high power rocketry. Barrowman stability analysis, full drag modelling, motor integration, and real flight data overlay — all in your browser, no install required.

Free to use · No account required · Built by 434 Aerospace

7

DRAG COMPONENTS

RK4

INTEGRATION METHOD

ISA

ATMOSPHERE MODEL

4,700+

THRUSTCURVE MOTORS

0

INSTALL REQUIRED

WHAT APEX DOES

Everything you need before launch day

Built for L1 to L3 certification flights. Covers the full pre-flight workflow from motor selection to stability verification.

🎯

Barrowman Stability Analysis

Centre of pressure calculated using Barrowman + Rogers Modified Barrowman body carryover, with DATCOM 3D Jones supersonic correction for M > 1.2. Real-time stability margin in calibers, dynamically tracked through the full flight envelope.

Core Physics

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Full Drag Model

Seven-component drag breakdown: skin friction, body form factor, nose pressure drag, fin friction, fin interference, fin wave drag, and base drag — including power-on plume correction during motor burn. Cd vs Mach plotted automatically.

Core Physics

⚡

Motor Integration

Load any RASP .eng motor file or search 4700+ motors from ThrustCurve.org directly in the app. Thrust curve parsed and integrated. Propellant mass burn-off tracked through the flight.

Motor DB

📊

Flight Data Overlay

Import Blue Raven altimeter CSV files and overlay real flight data on simulated results. Compare predicted vs actual altitude, velocity, and acceleration in a single view. Back-calculates Cd from the coast phase.

Blue Raven

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Parameter Sweep

Sweep any geometry or mass parameter across a range and see how apogee and stability respond. Optimise fin geometry, nose cone shape, or mass budget without running individual simulations.

Analysis

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OpenRocket File Import

Import an existing OpenRocket .ork design file to automatically populate your rocket geometry — no manual re-entry needed. Extracts airframe dimensions, nose cone shape, fin geometry, and component masses for CG estimation.

.ork Import

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Engineering Calculator Suite

Standalone engineering calculators built into the workflow — ejection charge sizing (black powder & CO2), vent hole sizing for barometric altimeters, parachute selection with an 85-entry manufacturer database, and fin flutter analysis. No external tools needed.

Calculators

SEE IT IN ACTION

The full HPR workflow in one tool

From motor selection to post-flight analysis — Project APEX covers every step

Full flight simulation — altitude, velocity, Mach, acceleration, and drag in one view

Stability analysis — CP vs CG tracking through the flight envelope

Aerodynamics tab — Cd vs Mach with full component breakdown

Parameter sweep — optimize geometry across a defined range

Blue Raven overlay — real flight data vs simulated prediction

GETTING STARTED

Up and flying in four steps

No account. No install. Just open the simulator and start

Load your motor

Search ThrustCurve.org directly in the app or drag and drop a RASP .eng file. Thrust curve parsed instantly.

Enter rocket geometry

Airframe diameter, length, nose cone shape, fin dimensions. Or load a saved CSV config from a previous session.

Run simulation

RK4 integrator steps through the full flight. Apogee, peak velocity, stability margin, and max-G all computed in under a second.

Analyze and export

Compare results, run parameter sweeps, overlay real flight data, and export the full simulation to CSV.

UNDER THE HOOD

Physics built for

serious rocketry

APEX isn’t a simplified toy model. The physics engine implements the same equations used in professional simulation tools — fully documented and open for inspection.

ISA Standard Atmosphere — three-layer temperature and pressure model to 32 km
Barrowman + Rogers Modified Barrowman CP, with DATCOM 3D Jones supersonic correction for M > 1.2 — validated to 1.3% on an M2.26 benchmark flight
RK4 numerical integrator at 20 Hz — 0.05s timestep with dynamic CG tracking as propellant burns
Seven-component drag model with power-on base drag plume correction for accurate high-thrust flight predictions
Fin flutter analysis using Bennett / NACA TN 4197 — T2T reinforcement and material shear modulus tracked vs altitude

// Barrowman + DATCOM supersonic fin CNa — SI units function computeCP(p, mach = 0) { const CNa_n = 2.0; // nose (slender body theory) // M < 0.8: PG subsonic | M ≥ 1.2: DATCOM 3D Jones const CNa_f = M >= 1.2 ? K*N*(4*AR/(AR*β+2))*(A_fin/Aref) // DATCOM : K*(4*N*sd²) / (1 + √(1 + (2*lm/(CR+CT))²)); // Barrowman return { Xcp: (CNa_n*Xn + CNa_f*Xcp_f) / CNa, stabMargin: (Xcp - Xcg) / d }; }

Ready to sim your next flight?

Free, browser-based, and built by the same people who fly HPR rockets. No signup. No ads. Just the simulation.