I used a D20-4W Aerotech White lightning motor in 2 rockets last weekend and both motors ejected out the back even with a tight engine hook in place

[tbsb9595]

How does this happen and how do I stop it? Thanks, Tom

 

[jnmiller]

Try wrapping a thin strip of masking tape around the hook and motor at the aft end

 

[dhbarr]

A breadbag tie can also work, or a small zip tie. Basically anything to keep the hook from bending out.

 

[waltr]

Try wrapping a thin strip of masking tape around the hook and motor at the aft end

I use tape on every motor held with a hook since I have had too many eject past the hook.

 

[KenECoyote]

How does this happen and how do I stop it? Thanks, Tom

View attachment 621795

Can you please post pics of the engine installed in your rocket? This would allow us to better diagnose a possible issue.

Sometimes the engine hook itself can be improved by simply bending the retaining part slightly more towards the motor.

Some motors have areas meant for the hook and not placing it correctly will not retain the motor in place enough at ejection. Example:

 

[kuririn]

Make sure your nose cone is not on too tight.

 

[KenECoyote]

Can you please post pics of the engine installed in your rocket? This would allow us to better diagnose a possible issue.

Sometimes the engine hook itself can be improved by simply bending the retaining part slightly more towards the motor.

Some motors have areas meant for the hook and not placing it correctly will not retain the motor in place enough at ejection. Example:
View attachment 621831

Example for engine hooks: