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.

Inputs

Motor diameter (mm)

Motor mass (g)

Peak thrust (N)

Estimated max velocity (m/s)

Rocket total mass (kg)

Ejection delay (s)

Tab to move between fields

Results

Worst-case retention force (N)

455.1

Ejection charge force (N)455.1

Deceleration inertial force (N)1.2

Peak deceleration (G)2

Required retention (N, 2x safety)910.2

Friction Fit OkNo

Tape OkNo

Clip OkNo

How to Use This Calculator

Enter Motor diameter (mm), Motor mass (g), and Peak thrust (N).
Set Estimated max velocity (m/s), Rocket total mass (kg), and Ejection delay (s).
Review the Worst-case retention force (N) result.
Use Ejection charge force (N) and Deceleration inertial force (N) to inform your decision.

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