Tri-Fold Shock Cord Mounts, Part 2

The tri-fold was first shown first in the 1968 catalog and on the AeroFin model, DOM Plan 53.
This illustration is from the 1969 Estes Catalog "Yellow Pages" showing the Alpha construction - HERE

Notice the dashed lines showing the shock cord position when the mount is folded.
This angled placement of the rubber cord keeps the mount flatter against the inside wall of the body tube. A flat mount is important considering Estes used these mounts in models as small as a BT-5.
Imagine cramming a 12" parachute in a BT-20 model past the thick tri-fold mount.

From an older blog post, how to glue a flatter tri-fold mount - HERE


Over the years, there was inconsistency in the tri-fold assembly.

This shows the shock cord glued first to the Section 1, followed by 2 and 3.
The mount is glued into the tube without saying how far it should be set back to allow the nose cone shoulder to fit.
Different models show the mount glued flat side up, others with the flat side down.

This illustration is from the Prime Number Explorer  kit, #0891.

Here the shock cord is glued to the second, middle section of the tri-fold.

The newer instructions do tell you how far to set it back in the tube.

Nearly all my builds now use a Kevlar line attached to the engine mount.

Unlike the tri-fold, a Kevlar line is out of the way without much to block a parachute ejection.