Saturday, February 4, 2017

Estes Sprint XL #7224 Build, Part 4, Engine Mount & Kevlar

Look close at the ends of the tail cone. There is a slightly raised molding lip.
I used my sanding block with 220 grit to straighten out the sides.

The engine block sits inside the end of the engine mount tube. Use a D engine casing to set the block so it won't be glued in at an angle.

The instructions say to glue the upper centering ring even with the top of the engine mount tube.

TIP: For a stronger mount the ring was glued about 1/8" down from the top. This way you could put a glue fillet on both sides.

A 150 lb. Kevlar line was tied below the upper ring.

The mount is set beside the main body tube to get the right length of line before the mount is glued in.. You'll want the Kevlar tie loop below the top of the body tube to prevent a zipper tear.


  1. What is the knot you used when you tied the Kevlar line below the upper ring?

    I used a noose slip knot, secured the tail of the Kevlar when I placed tape to secure the engine hook in the same section. Finally I placed a dab of wood glue on the knot itself.

    Was that overkill?

    1. Hi Sparky,
      I tend to use a square knot. A bowline could be used here, much like your noose slip knot. A bit of white or wood glue can help especially if the knot could slip. It's not overkill if you are sure of the attachment. Never use CA (Super Glues) to set a knot. It runs up the line and makes the string very brittle.