Amateur Rocketry
Planning calculators for amateur rocketry — estimates from industry-style inputs.
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Rocket Motor Selection Calculator
Determine the right NAR motor class for your rocket based on mass, target altitude, and drag estimates using energy-based delta-V and impulse calculations.
Recovery System Calculator
Size your rocket parachute for a safe descent rate. Calculates canopy diameter, area, landing energy, and drift distance using aerodynamic drag equations.
Stability Calculator (Rocket)
Calculate your rocket's static stability margin using the Barrowman equations. Determines CP and CG separation in calibers for safe flight.
Fin Flutter Speed Calculator
Calculate the critical flutter velocity for rocket fins based on material shear modulus, fin geometry, and altitude using the NARTS approximation.
Launch Lug Sizing Calculator
Calculate rod/rail exit velocity and minimum guide length for a safe launch. Accounts for thrust, gravity, friction, and wind speed.
Motor Retention Calculator
Calculate ejection and deceleration forces on your rocket motor to choose the right retention method -- friction fit, tape, clip, or threaded retainer.
Altimeter Bay Design Calculator
Design your rocket's avionics bay. Calculate internal volume, verify component fit, and size vent holes for accurate barometric altitude readings.
Dual Deploy Calculator
Size drogue and main parachutes for dual-deployment recovery. Calculates chute diameters, descent times, opening shock, and black powder ejection charges.
Rocket Drag Coefficient Calculator
Estimate total Cd by summing nose, body, base, fin, and interference drag using semi-empirical methods from Hoerner and Mandell/Caporaso/Bengen.
High-Power Certification Calculator
Plan your NAR/TRA Level 1, 2, or 3 certification flight. Predicts altitude, velocity, and Mach number from motor and rocket specifications.