Lawn Dart Rocketry SLAT/S Build, Part 7, Engine Mount

I used an Odd'l Rockets heavy wall BT-20 tube for the engine mount. These tubes are thicker than a standard BT-20 and only available from JonRocket.com
The inside diameter is the same as a standard BT-20. The outside diameter is a bit wider. To fit a standard 20/50 ring, the inside is slightly peeled to fit the tube. This is easier than you'd think. The inset picture shows a good friction fit.

The rings are then notched to clear the engine hook.
The 150 lb. Kevlar shock cord line is tied in a loop and slips under the upper bend of the engine hook.

The upper ring is slid over the top bend of the engine hook for a stronger mount.





The rest of the construction is standard. The lower ring is glued 3/4" from the end of the BT-20H tube to allow the hook to flex.
An engine block is glued on top of the upper bend of the hook.