The last thing you want to do it spit the motor out at ejection... that way you lose the rocket AND the motor casing. Rowes Retainers are an essential flight safety ingredient... and they look very cool, too.
All Standard Retainers are made from Aerospace Spec HE30 aluminium and are anodized to MIL-SPEC Type 2 Class 2 (Available in red only). All mounting hardware is included. Rowes Retainers can be retro fitted to previously built vehicles.
Each Retainer fits (nests) inside the next size up. So a 29mm will fit into a 38mm Retainer and a 38mm will fit into a 54mm Retainer, etc. This is especially useful if you are flying a rocket with a motor reducer.
This retainer fits Aerotech 75mm RMS cases, Cesaroni Pro75 cases (?), Dr Rocket 75mm RMS cases and Hypertek hybrid motors. It may work with others - ask! The outside diameter is 3.90 inches so it will fit (just) nominally 4 inch vehicles
Rowes Retainers make both standard and coned retainers. Please note : Cones will not nest in each other, but Standard Retainers will nest in Coned Retainers.