Theta 13 Aerospace Speciality Products Page 3
1/4" mark. Apply another thin layer of glue around the tube at the other 1/4" mark and slip the
remaining centering ring into place.
A
pply a thin layer of glue inside the end of the tube and slip one
engine block in the end and then
the second right behind it and push both into place as shown in Figure A. Be sure that the blocks
are on the same end of the tube as the shock cord is and the end of the second block is even with
the end of the engine tube. Set the engine mount aside to dry.
Kevlar Shock Cord
Engine
Blocks
Engine Tube
1/4" Mark
1/4" Mark
Centering
!
Rings
Make marks at
!
ends of arrows
!
on guide
Align marks at
!
ends of guide
Body
!
Tube
Figure A
Figure B
⎕
2) Locate the white body tube. Very lightly sand the outside the of the tube with medium or fine
sandpaper until the surface just loses its shine. This will allow the glue to penetrate the paper of the
tube and the fins to stick to the tube better. Locate the Tube Marking Guide on page 9 and cut it out.
Wrap the guide around the body tube - line up the marks on each end to align the guide (see Figure
B). Use a piece of tape to hold the guide in place. With a sharp pencil mark the body tube at the
arrows at the end of each line for the three fins and the launch lug. Be sure to note which line is for
the launch lug. Remove the guide from the tube.
Using something such as a door frame (as shown in Figure C, try not to get pencil marks on the
door frame while you do this!), a piece of metal angle (see Figure D), or a drawer edge, connect the
marks and extend each line the full length of the tube.
On each of the 3 fin lines, make a mark 1/8" (0.125") from one end of the body tube (this will be the
bottom end of the tube) and also make a mark on the launch lug line 2" from the bottom end of the
tube.
Figure C
Figure D
⎕
3) When the engine mount has completely dried it is time to glue it into the body tube. First take
the loose end of the shock cord and thread it through the top end of the engine mount tube (the end
the engine blocks are in) so that it hangs out the back of the tube (see Figure E) - this will help to
prevent from getting glue on the shock cord while you are gluing the engine mount in.
