Pull Kevlar through
inside hole on the
grooved ring
Use dowel to place
glue ring inside
tube here
Engine block
Glue string
and ring into
place
CR
CR
3in
Step 12
The sustainer stage is the top stage of the rocket.
9. The
sustainer motor mount tube
is the longer
29mm diameter tube that is 7 inches (178mm) long.
Mark the tube with a pencil for the location of the cen-
tering rings. One mark should be 2 ⅝” from one end,
and the other is ⅛” from the opposite end.
10. Test fit both large centering rings (29/2.6") onto the
motor mount tube
. Sand the inside to adjust the fit if
necessary. Then take one of the rings and place it on
the tube. Apply a ring of glue around the 2⅝” line mark-
ing and slide the ring onto the line.
11. Tie one end of the yellow shock cord near the 1/8"
line you drew in the previous step. Now put a thin line
of glue around the tube at the same marking. Before
the glue dries, thread the shock cord through the hole
in the remaining centering ring. Place the ring on the
tube and slide it over the glue. Pull the shock cord
tightly against the centering ring. Cover the shock cord
with a fillet of glue. Allow the glue time to dry.
12.
(Optional Engine Block)
This step will put an
engine block in the motor mount of the sustainer
stage.
If you plan on using composite motors in
this rocket, we suggest you skip this step, because
composite motors already have a motor block built
into them.
Use a wood dowel to spread glue in the
motor mount
. The band of glue should go approxi-
mately 3” (76mm) from the end where the yellow shock
cord is attached. Slide the green centering ring into
the
motor mount
, until it is centered in the glue. As a
check, if you insert an Estes 29mm motor into the tube,
the end of the motor should stick out ½” (12.7mm).
Wipe out any excess glue.
13. Temporarily pass the shock cord through the
motor
mount
and out the rear. This will keep it glue free
when gluing it into the
sustainer tube
. Using a wood
dowel, apply glue just forward of the fin slots in the
sustainer tube
. Also put a glue ring inside the tube on
the other side of the fin slot (just before the end of the
tube). There is a small cutout in the
sustainer tube
so you can gauge how far to put the glue. Quickly and
smoothly insert the
motor mount
into the aft end of the
sustainer tube
. The edge of the aft wooden centering
ring should be centered in the slot just to the rear of
the fin cutout. Wipe out any glue inside the back end of
the
sustainer tube
quickly. Any excess glue will make
it hard to insert the red coupler to join the two stages
together. Once the glue is dry, pull the shock cord back
through the
motor mount
and out of the front of the
sustainer tube
.
Apply glue on inside of
line, slide ring into place
Pull cord snugly
against ring, add
glue fillets
Mark the tube at
these places
2
7in
in
5
8
in
1
8
Step 10
Step 11
Step 9
**Remove slotted pieces first**
Glue inside of the
long tube here
The aft centering ring will be
visible through
this slot
Aft centering ring will
be visible from this slot
in the tube
Step 13
Booster Fins
Sustainer Fins
Step 14
Page 3
Construction of the Sustainer Motor Mount
Attaching the fins
P/N 31
106
14. Note that the tabs on the wooden fins are different
lengths, and are in different locations. The
Booster
Fins
have wider tabs, and they are closer to the bot-
tom edge of the fin. Whereas the
Sustainer Fins
have
smaller tabs and they are closer to the top edge of the
fins.
Use the diagram to the right to ensure that the fins
are glued into the correct body tubes.
