Estes 18mm Engine Retainer Set
An Estes 18mm engine retainer is used in place of an engine hook and allows you to easily change engines by turning the engine cap. Works great for those rockets that don't have fins that extend beyond the bottom of the body tube which normally wouldn't stand up due to the engine hook sticking out. This 18mm engine retainer set also helps to protect the bottom of the rocket when it lands. It's best used with BT55 size or larger model rockets to allow enough room to screw and unscrew the engine cap.
Installation is a breeze - just leave the engine hook off when making the engine mount, glue the engine block 2 1/2 inches from the end of the tube and finally glue the engine retainer to the end of the BT20 engine tube.
Includes: 3 - 18mm engine retainer sets and instructions.