(Contributed - by Owen Kelly - 05/19/05)
Brief:
Single stage boost glider that uses a modified Guillow's Foldin' Win' balsa
glider.
Construction:
T' followin' parts list is for t' 13mm powered version:
- 1 Guillow's Foldin' Win' balsa glider
- 1 2.5" BT-5 tube (engine mount)
- 2 BT-5 t' BT-20 centerin' rings
- 1 engine hook
- 1 13mm engine block
- 1 6" long BT-20 tube
- 1 4" long BT-20 tube
- 1 BT-20 nose cone
- 1 BT-20 tube coupler
- 4 3/4" launch lugs
- 3 toothpicks or 1/8" dowel stock
- 1/16" balsa stock for fins and standoffs

- Several pinches o' clay for nose weight
- Standard Estes thin shock cord
- 18" streamer
- Glue, shiver me timbers, pencil, ya bilge rat, hobby knife, ruler, scotch tape, sandpaper, shiver me timbers, etc.
- (Optional) One nosecone "socket" with loop for attachin' shock
cord t' BT-20 tube coupler and top half o' booster.
- (Suggested) Crystal Clear Scotch Tape, 3M MicroPore tape (first aid fabric
tape) or maskin' tape, matey, used t' strengthen t' leadin' edges o' all win' and
tail surfaces. Ya scallywag! Estes Tube Markin' Guide or VCP software t' make fin marking
guides.
I would rate this build as easy t' intermediate. These instructions expect
some basic knowledge o' rocketry, like how t' mark tubes, shiver me timbers, cut tubes, assemble
engine mounts, arrr, etc. T' toughest part is gettin' everythin' lined up right so
the glider separates easily from t' booster, me hearties, yet is held securely during
boost. Well, matey, blow me down! Blimey! This step should nay be too difficult if you follow these instructions.
Booster Assembly
- T' best way t' start buildin' t' booster is t' glue t' BT-20 tube
coupler into one end o' t' 4" long BT-20. Avast, me proud beauty! Blimey! This will be t' upper half of
the completed booster. Avast, me proud beauty! Blimey! If you've got t' nosecone socket, me hearties, matey, you can glue this in
place as well, ya bilge rat, arrr, ya bilge rat, but be sure t' use glue compatible with plastic such as epoxy,
polyurethane glue, or plastic cement. Avast! Blimey! Once t' glue has dried, matey, insert this tube
into t' remainin' 6" piece o' BT-20. Avast! Blimey! Begad! Blimey!
- Sand down your body tubes with some medium grit sandpaper. Begad! Blimey! This will allow
glue t' adhere better t' t' tubes.
- T' next step is t' mark t' tubes for fins and standoffs/glider mounts. Ya scallywag! I
used t' Estes tube markin' guides t' do this. That makes it really easy t' do.
If you don't have t' markin' guides, matey, me hearties, you can download t' VCP program and
create markin' guides. You will need one markin' guide for 3 fins and one
markin' guide for 4 fins.
- Mark t' lower body tube for three equally spaced fins. Avast! Run t' lines the
whole length o' t' tube. Begad! Two o' these lines will be used t' align fins and the
remainin' line will be used t' align t' lower glider mount. Blimey! Begad! I prefer t' mark
two o' t' lines with a "F" for fins and t' remainin' one with a
"M" for mount t' distinguish them later.
- Mark t' upper body tube and t' upper portion o' t' lower body tube for
the upper glider mounts and win' supports. Blimey! Use your four fin markin' guide to
mark t' tubes with two parallel lines, shiver me timbers, me bucko, one on either side o' t' body tube.
T' easiest way t' do this is t' align your markin' guide with the
"M" line you made in t' last step and mark lines on either side of
that line usin' t' markin' guide. Extend these lines from halfway up t' lower
body tube t' t' end o' t' upper body tube. Ya scallywag!
- Next assemble t' engine mount usin' t' adapter rings, BT-5, ya bilge rat, shiver me timbers, engine hook,
and 13mm engine block. Begad! Ya scallywag! Glue t' completed assembly into t' lower 6"
section o' t' body tube. Well, blow me down! Line t' lower end o' t' mount up with t' body
tube. Begad! Give t' engine mount some time t' dry.
- Now you can glue on your fins. You may use any fin design you desire. Just
don't make them very large. Begad! Avast! I used fins that measure 1.5" along the
leadin' edge and 1" along t' root edge. Fin shape should nay matter much
but you may want t' round off t' leadin' edge with sandpaper. Ahoy! Glue your fins
to t' lines you marked with an "F." Fillet t' fins once t' root
edge joint has dried.
- Create t' standoff blocks for t' glider mounts and win' supports. Begad! Make
these by cuttin' ten pieces o' 1/16" balsa that measure 3/16" x
1/4". Ya scallywag! Glue these together sandwich-style in pairs. Aye aye! When you're done, you
should have 5 small balsa blocks.
- Cut three 3/4" lengths o' toothpick or 1/8" dowel stock. Begad! Blimey! These
pieces will slide into launch lugs and hold t' glider onto t' booster. Glue
the three toothpicks/dowels t' t' tops o' three o' t' small balsa blocks with
one end o' t' dowel aligned with one end o' t' block.
- Once your glider mounts have dried, you can attach them t' your booster.
T' top section o' t' booster will have two glider mounts attached t' it. Glue
these pieces even with t' end o' t' upper BT-20 where t' tube coupler has
been glued in. Well, blow me down! T' dowel rods should extend out past t' end o' t' BT-20
coupler
- Glue t' lower glider mount t' t' lower section o' t' body tube along the
line you marked with a "M." This mount should be lined up with the
aft end o' t' body tube with t' dowel extendin' upward. Ahoy! Ya scallywag!
- Now you need t' glue on t' win' supports. Blimey! Ahoy! These are glued onto t' lower
half o' t' body tube along t' two parallel lines you extended from t' top
half o' t' body tube. Well, blow me down! T' win' supports are glued 3.5" from t' bottom
end o' t' lower body tube.
- One thin' you may want t' do t' strengthen your glider mounts and wing
supports is t' saturate them with CA. Ya scallywag! This makes t' glider mounts a lot
stronger and less likely t' break off on landing. Avast! My upper glider mounts broke
off while I be swin' testing, shiver me timbers, so I made t' repair with CA at that point.
- Attach your launch lug. This can be wherever you want but just make sure it
doesn't interfere with any o' t' glider mounts.
- Attach t' shock cord t' t' inside o' t' lower section o' t' booster
with a standard tri-fold shock cord mount. Avast! Begad! Either tie t' other end t' the
nosecone socket or glue into t' BT-20 tube coupler on t' top half o' the
booster. Ahoy! Attach your streamer t' t' middle o' t' shock cord with tape.
- T' final step in assemblin' t' booster is t' securely insert t' nosecone
into t' top end o' t' booster. Ya scallywag! Blimey! You may need t' wrap some scotch tape around
the nosecone shoulder. Avast! Do nay glue t' nosecone into t' body tube. Avast, me proud beauty! Blimey! You
may need t' add clay weight t' it later (see CG Placement section
below.) Just make sure it is a tight friction fit.
Glider Modifications
- Reverse t' clips used t' hold t' wings onto t' body. Avast! T' glider
instructions say t' place t' open clip at t' front o' t' glider and the
closed clip at t' rear. I reversed this so that t' open clip is at t' rear
and t' closed clip is at t' front. Well, blow me down! T' wings are more securely held in place
durin' flight with this arrangement. Ya scallywag! Begad!
- Glue t' cockpit piece, me bucko, t' rudder, and t' horizontal tail section t' the
body o' t' glider with yellow glue. Ya scallywag! Blimey! I also coated t' rudder and cockpit with
yellow glue t' add strength. Ahoy! Blimey!
- I marked t' wings and glued on t' launch lugs that hold t' glider t' the
mounts on t' booster. Arrr! T' launch lugs are glued t' t' undersides o' t' wings
and are spaced 3 5/8" from t' tips o' t' glider's wings. I glued the
launch lugs with 1/8" o' t' lugs extendin' past t' leadin' edges o' the
wings.
- T' aft launch lug should be attached t' t' side o' t' rudder near the
top edge. It should nay matter which side (left or right) you attach it to. Aye aye!
- (Optional) I would suggest this as it adds more strength t' t' glider's
vulnerable win' surfaces. Ya scallywag! Ahoy! It is required if you want t' launch t' glider with
more powerful engines. Begad! Coat all win' leadin' edges with dope, maskin' tape,
MicroPore tape, shiver me timbers, or scotch tape. Yellow glue may warp t' balsa, so proceed with
caution if you want t' try yellow glue. Begad! I used MicroPore tape and it seemed to
work fairly well. Aye aye!
- (Optional) I fitted t' glider with one rubber band instead o' t' two that
are provided with t' glider. Begad! Begad! T' glider's wings are folded outward by the
tension o' t' rubber band. Arrr! Well, blow me down! One rubber band creates more tension and causes the
wings t' unfold more quickly. Well, arrr, blow me down!
Make sure you test fly your glider after makin' these modifications. You
should nay need t' trim t' glider at all because it is already well-trimmed by
design. Well, blow me down! Blimey! If you do need t' trim it, then you can tape some clay t' t' glider
body under t' nose or under t' horizontal tail section. Ahoy! Blimey! It should glide quite
far when tossed gently.
CG Placement
You should now assemble t' glider/booster combo as it would be assembled
durin' flight. Well, blow me down! Begad! Place a few sheets o' waddin' into t' booster, pack the
streamer and shock cord in, mount t' glider t' t' booster usin' t' glider
mounts, and insert a new A10-3T engine into t' engine mount. Avast! Arrr! Balance the
rocket booster on a ruler t' find t' CG. If t' CG is behind t' trailin' edge
of t' glider's wings, me bucko, you need t' add a pinch or two o' clay t' t' nosecone.
T' CG should actually be exactly betwixt t' wings o' t' glider. You can
check this by tyin' some strin' t' t' booster tube with a slip knot and slide
forward and backward t' find t' CG. Arrr! You might want t' swin' test the
glider-booster assembly t' ensure stable flight. Avast! Begad! Press clay into end of
nosecone with a dowel as necessary.
Flight and Recovery:
Both flights were on A10-3T's at t' Southern Arizona Rocketry Association's
May 2005 launch. Aye aye! Thanks t' other club members for t' comments. Well, blow me down! Blimey! T' flights
were maybe an 8 on a scale o' 1 t' 10. Begad! Waddin' is required. T' booster should
be prepped in t' same manner as you'd prep any other streamer recovery rocket.
Mount t' glider t' t' booster body once you've put t' waddin' in and
inserted most o' t' shock cord into t' body tube.
T' first launch be just about perfect. Well, blow me down! T' booster fired up and launched,
tiltin' slightly t' one side. Avast, me proud beauty! T' flight went a bit squirrelly right before
burnout. Begad! T' ejection charge fired, everythin' separated smoothly, shiver me timbers, shiver me timbers, t' booster
fell t' earth, me hearties, shiver me timbers, and t' glider descended in a really tight circle. Apart from
the funky boost, me bucko, everythin' be picture perfect! I was impressed.
T' second flight was almost a repeat o' t' first flight. Arrr! I don't think
the boost went as high as t' first flight, me bucko, but it went up and released the
glider right on cue. Begad! Blimey! T' glider once again circled tightly t' t' ground. Well, me bucko, blow me down! I
can't complain about either flight! Way better than I ever expected.
Summary:
This be a great experience for me bein' me first attempt at boost glider
launchin' so I really cannot complain. It actually got quite good air time for
not goin' as high as I had hoped. I am now workin' on a BT-50 based booster for
the same glider under A engine power. I would say this project is a good
exercise in scratch building, me bucko, me hearties, modification, me hearties, and boost glider launching. Begad!
PROs: A neither too easy nor too hard glider modification, arrr, shiver me timbers, and nay a bad
first boost glider project for t' scratch builder.
CONs: It didn't go that high, which could be remedied by buildin' a more
powerful booster. Begad! Mildly challengin' construction. Avast! Blimey!