Apogee DRACO BG User manual

The Draco BG is a model boost glider (BG) based on the
real-life Boeing GBU-39 SDB (Small Diameter Bomb) which
originally was an air-drop ordinance and was later modied
for launching from ground vehicles. This modied version is
known as the GLSDB (Ground-Launched Small Diameter
Bomb) and is a precision weapon system that allows delivering
a payload of 93kg (205 lbs) to a location within a range of 150
km (93 mi) from the mobile launch platform. Development of
the GLSDB was a joint project of Boeing and the Saab Group.
The Draco BG copies the overall conguration of the GLSDB
and the unique folding wing arrangement.
Despite the fancy wing mechanism, ights of the Draco
BG model are simple. It launches upward on 24mm diam-
eter rocket motors. The simple interstage/wing-lock system
ensures reliable transition of the upper stage to glide congu-
ration while the booster recovers under a parachute. While a
challenging build, the Draco BG is a fantastic rocket for those
interested in mechanical design, gliders, and military history.
Item # Item Name Qty
10091 AT-24/3.75” (Motor Tube) 1
10151 AT-41.6/9” (Booster Tube) 1
10154 AT-41.6/18” LC (Fuselage Tube) 1
12976 #4 Flat Washer 4
12977 #4 3/16”x1/4” Unthreaded Off-White Nylon
Standoff 5
12978 #4 3/16”x5/32” Unthreaded Off-White Nylon
Standoff 2
12979 4-40 x 1/2 Black Nylon Panhead Screw 7
13031 CR-18/24 1
13035 CR-24/29 1
13123 AC-41.6/1.5” LC 1
13051 1/8" Launch Lug 1" Long 2
13056 1/4" Launch Lug 3" Long 2
14263 1/8" x 2.5" Wood Dowel 2
15015 CR-24/41.6 Cardstock (Rectangle) 1
15487 Draco BG Jig Sheet Cardstock 1
15488 Draco BG Parts Sheet A 1/8”x4” Balsa 1
15489 Draco BG Parts Sheet B 1/8” Ply 1
15490 Draco BG Parts Sheet C 1/16” Ply 1
15731 Draco BG Wing Sheet 1/8”x4” Balsa 2
15732 Draco BG Fin Sheet 1/8”x4” Balsa 1
15733 Draco BG Stabilizer Sheet 3/32”x4” Balsa 1
19469 PNC-41mm (BT-60) 1
24003 #117B Rubber Band 1
24044 Crimped "E-size" Engine Hook 1
29090 12" Printed Nylon Parachute 1
29518 100# Kevlar x 5 feet 1
29600 Clay Nose Wt 5g 1
31271 Instructions Sheet A 1
31272 Instructions Sheet B 1
31273 Instructions Sheet C 1
31274 Instructions Sheet D 1
31275 Instructions Sheet E 1
31276 Instructions Sheet F 1
39059 Face Card 1
41116 Decal Sheet 1
Skill Level 5
Extremely Challenging
Draco BG Parts List
Optional Tools / Finishing Supplies
Fin Alignment Guide (P/N 35546)
Flat Needle File
Wood Filler
Sanding Sealer
Extra Fine Sandpaper (600 grit)
Spray Paint
Wood Dowel
Ruler or Calipers
Needed Tools and Materials
Hobby Knife with Sharp Blades
Scissors
Razor Saw
Wood Glue
Thin CyAAdhesive
Medium CyAAdhesive
Masking Tape
Medium and Fine Sandpaper (180, 320 grit)
Aluminum Angle
4-40 Tap Page 1
Assembled In USAKit #05065
Skill Level 5
Manufactured in the USA by:
Apogee Components Inc.
Colorado Springs, Colorado, USA
www.ApogeeRockets.com
Instruction Sheet A: P/N 31271 *Updated 9/1/2023

Assembly Booster Steps
1. Mark the motor mount tube (AT-24/3.75”) with a pencil
1/2” (13 mm) from either end. Cut a 1/8” (3mm) wide slot,
1/4”(6 mm) from the front of the motor mount tube.
Step 1
Fin - X
Fin - Y
Fin - Y
Booster Fin
Marking Guide
Overlap
Wing Lock Wing Lock
Launch Lug
Fin - X
Forward
Edge
Forward
Edge
Boattail
Marking Guide
Vane
Vane
Vane
Vane
This image outlines the basic nomenclature used in this instruction booklet for major parts of the Draco BG.
Additional exploded views of the more complicated assemblies are included later.
Horizontal Booster Fin
Launch Lug
Wing Lock
Vertical Booster Fin
Boattail
Horizontal Stabilizer
Vertical Stabilizer
Launch Lug Stay Wing
Wing Frame Main Wing Nose Cone
1/2” (13mm)
1/2”
(13mm)
1/4” (6mm)
1 inch
Page 2

2. Using a sharp hobby knife, remove the two CR-24/41.6
centering rings from the small cardstock sheet (P/N
15015).
3. Install the motor hook by sliding it into the cut slot in the
tube with the hook end hanging over the aft end of the
tube. Wood glue one cardstock centering ring into place at
the line 1/2” (13 mm) from the aft end of the motor mount
tube.
4. Tie the shock cord around the middle of the motor mount
tube.
5. Route the shock cord through the other cardstock center-
ing ring then wood glue the centering ring into place at the
line 1/2” (13 mm) from the front of the motor mount tube.
Pull the shock cord tight against the backside of the cen-
tering ring and apply a wood glue llet to ensure the shock
cord stays in place.
6. Route the shock cord through the larger green centering
ring (CR-24/29) and using wood glue, secure the ring into
place at the front of the motor mount tube ush against the
forward centering ring.
Step 4
Step 5
Step 6
Step 2
Step 3
1/2”
(13mm)
1/2” (13mm)
Mount rotated
Page 3
Instruction Sheet B: P/N 31272

7. Put a ring of wood glue inside the front lip of the motor
tube. Seat the smaller green centering ring (CR-18/24) in
the front of the motor mount tube with wood glue. Install
the ring so that it sits against the engine hook so that it
acts as an engine block.
8. Using scissors, cut out the n marking guide and tape it
around the 9” long, 41.6mm diameter (BT-60) tube. Copy
marks for all of the lines onto the tube with a pencil. It is
also useful to label the different lines and the forward end
of the tube to coincide with the forward label on the mark-
ing guide. This is the booster tube.
9. Extend the lines along the length of the tube using an
aluminum angle to ensure the lines are straight along the
tube. The n lines can be drawn about halfway from the aft
end of the tube and the support lines and launch lug line
can be drawn about halfway from the forward end of the
tube.
10. Measure 3/4” (19mm) from the front of the tube, and using
a pencil, mark the location on the upper support lines.
11. Route the shock cord back through the center of the motor
tube and glue the motor mount assembly into the booster
tube. Using a dowel, apply wood glue at points 1/2” (13
mm) and 3” (76 mm) deep inside the tube, then slide the
motor mount assembly into the tube so that the aft end of
the motor mount tube is ush with the aft end of the boost-
er tube. Set aside to dry.
Step 9
Step 10
Step 11
Step 7
Fin - Y
Fin - X
Wing Lock
Wing Lock
Step 8
Forward
3/4” (19mm)
1/2” (13mm)
3” (76mm)
Forward
Forward
Forward
Page 4

12. Before removing the booster ns from the 1/8” balsa sheet
(P/N 15732), sand the surface smooth on both sides using
a ne grit sandpaper (320 grit).
13. Remove the booster ns from the sheet using a hobby
knife and sand the edges of the parts to remove any rem-
nants of tabs.
14. Remove the two wing lock supports (CC) from the 1/8”
balsa sheet (P/N 15488) using a sharp hobby knife and
sand off the remnants of any tabs using ne grit sandpaper
(320 grit).
15. Using ne sandpaper (320 grit) smooth and bevel one
end of one of the 2-1/2” long (63 mm) hardwood dowels.
Glue the other (at) end of the dowel into the notch in one
of the wing lock supports (CC), tape it in place and let the
assembly dry. Repeat the sanding and assembly for the
second dowel and support. Optional: sand one of the
dowels 1/8” (3mm) shorter than the other so that the
wing locks can be aligned separately, making ight
preparation easier.
16. Using wood glue, glue the ns onto the booster tube with
the ns aligned on the lines marked on the tube. The
larger ns provide stability in the plane of the glider wings
and should be attached to the Fin-Y lines on the tube.
The shorter ns are attached on the Fin-X lines and fall
between the wing lock lines on the top. A n alignment jig
can be helpful to ensure accurate construction but the ns
are too tall for most jigs to completely enclose the ns and,
therefore, only the front sections of the ns will be retained.
Take care to align the ns accurately along the long axis of
the tube to ensure the straightest boost. Allow the ns to
dry before continuing.
Step 14
Step 15
Step 16
Step 12
Step 13
Bevel Ends
Yes
No
Page 5
Instruction Sheet C: P/N 31273

17. Remove the wing lock support frame (T) from the 1/16”
plywood sheet (P/N 15490). Using a small drop of wood
glue at the front of each balsa support, slide the two wing
lock assemblies as far as they will go into part T. Then glue
the whole wing lock assembly onto the booster tube with
the support frame 3/4” (19 mm) from the forward end of the
tube. The alignment lines drawn on the tube are placed at
the outside edges of the wing lock supports. Take care that
the supports and pins are aligned with the long axis of the
tube to ensure reliable separation and wing extension.
18. Wood glue one 1/4” x 3” long launch lug into place cen-
tered on the marked line and ush with the front edge of
the booster tube.
19. Using a sharp hobby knife, remove the two piston frames
(Q and R) and the piston ring (S) from the 1/8” plywood
sheet (P/N 15489).
20. Apply wood glue to the notches of the two piston frames
(Q and R) and slide them together.
21. Apply wood glue as shown on the front edges of the as-
sembled piston frame and slide the piston ring into place.
Add wood glue llets along the joints between the piston
frames and piston ring for strength.
Step 19
Step 20
Step 21
Step 17
Step 18
3/4” (19mm)
Fillet all joints
Wing lock support frame
Page 6

22. Apply a bead of wood glue to the inside of the short red
coupler tube at roughly the middle and slide the piston
frame and ring assembly into the tube. To correctly align
the frame and ring in the tube, place the tube and the at
end of the frame against the table so that they are ush.
Ensure that the edges of the piston ring have llets where
they touch the coupler tube but leave the slots clear so
that the glider is able to slide into place later.
23. Apply wood glue llets to the joints at the base of the ns,
the launch lug, and the supports by applying a bead of
wood glue and shaping the llet with the tip of a nger.
24. Once the booster has dried, test t the piston in the tube
witht the loop side facing aft, and adjust so that it ts snug-
ly with little or no wobble but does not require excessive
force to move. If the piston is tight enough that it becomes
difcult to move, sand its surface with a ne sandpaper
(320 grit) until it moves more easily.
25. Pass the shock cord back through the motor tube then tie
it onto the loop in the piston. Apply tape to the tail of the
shock cord to prevent the knot from coming undone.
26. Attach the parachute by collecting the center of the para-
chute’s shroud lines. Then pass them through the loop on
the piston, and pull the parachute back through the ends,
pulling the knot tight.
Step 24
Step 25
Step 26
Step 22
Step 23
Apply glue inside
tube
Frame ush
with tube
Sand for
sliding t
Tape
Page 7
Instruction Sheet D: P/N 31274

27. The physical build of the booster is now complete and the
parachute and piston can be installed in the end of the
tube to await nishing.
Glider Assembly Steps
Wing Frame:
28. Using a sharp hobby knife, remove the main wing frame
(B) and the two wing frame alignment guides (E and F)
from the 1/16” plywood sheet (P/N 15490) as well as the
upper wing frame (A) and the forward and aft wing frame
spacers (C and D) from the 1/8” balsa sheet (P/N 15488).
Remove and discard the many small cutouts from with-
in the main wing frame (B), the hexagonal pieces in the
upper wing frame (A) and sand down any prominent tab
remnants on all the parts using ne sandpaper (320 grit).
Step 27
Step 28
3x J
A
B
F
D
V
2x EE E
C
Label Part
A Upper Wing Frame
B Main Wing Frame
C Forward Wing Frame Spacer
D Aft Wing Frame Spacer
EForward Wing Frame Alignment Guide
F Aft Wing Frame Alignment Guide
J Hex Insert
VStay Tie Frame
EE Stay Tie Guide
Page 8

29. Apply a small amount of medium CyA adhesive to the slot
in the forward spacer C and install the tabs of the align-
ment guide E (opposite the curved side) such that the tabs
poke through the frame C and the curved portion is ush
with the surface of the balsa in the center. Check that the
frame is square to part C and allow the adhesive to hard-
en.
30. Dry t the assembly onto the main frame B on the side
opposite the engraving on the surface of B and using a
pencil, trace around the forward spacer C.
31. Apply medium CyA adhesive to the main frame B within
the pencil outline then install the assembled spacer C and
frame E onto the main frame B. Allow the tabs on E to
align the large parts and check that the points on the balsa
part C and the plywood part B are touching to ensure cor-
rect alignment.
32. Apply medium CyA adhesive uniformly to the upper (en-
graved) side of main frame B in the area covered by the
upper frame A (outline marked by engraving). Glue the up-
per frame A into place, taking care to align the two frames
along the outside edge.
33. Aligning the engraved dot on part F at the forward end of
the slot, place the alignment tab F on the bottom of the
main frame B, opposite the engraving and the upper frame
A that was just installed. Apply a couple of drops of thin
CyA adhesive to tack part F in place during the next step.
Step 29
Step 30
Step 31
Step 32
Step 33
Flush
Engraved side down
Engraved side up Edges align
Engraved side of
frame down
Engraved dot
Page 9
Instruction Sheet E: P/N 31275

34. Apply medium CyA adhesive to the slot and one surface of
the aft spacer (D) then slide it over the alignment tab (F).
35. Using a sharp hobby knife remove three of the bolt hex
inserts (J) from the 1/8” plywood sheet, parts sheet B (P/N
15489).
36. Insert the plywood inserts (J) into the three pockets on the
upper side of the wing frame and secure them by running
a bead of thin CyA adhesive along the edge. Apply enough
adhesive that it will soak down into the joint and securely
hold the inserts in place.
37. Remove the stay tie frame (V) from the 1/8” plywood sheet
(P/N 15489) and the two stay tie guides (EE) from the 1/8”
balsa sheet (P/N 15488), then insert the balsa guides (EE)
into the plywood stay tie frame and secure by running a
bead of thin CyA adhesive along the joint. This assembly is
the stay tie and it holds the small (stay) wings together as
the wings fold and extend.
38. Once the glue has dried on the wing frame assembly and
stay tie assembly, use a ne (320 grit) sandpaper to sand
all of the edges – including inside the long slots – so that
they are slightly rounded and smooth. Removing imper-
fections and sharp edges reduces the likelihood that the
mechanism will catch during operation and increase the re-
liability of wing extension. Once sanded, set the frame and
stay tie aside for later assembly of the wing mechanism.
Step 34
Step 35
Step 36
Step 37
Step 38
Smooth the edges
D
J
J
JJ
“A” side up
EE
Page 10