Brief:
This LPR model breaks into three pieces at ejection, ya bilge rat, each section descendin' as a "maple leaf" recovery monocopter.

Construction:
T' parts list:

• 3 BT-20 tubes, me hearties, arrr, 3.5" long each
• 1 BT-20 balsa nose cone
• 3 piece o' basswood stock o' 18" x 3/8" x 1/8", me bucko, which is cut into 9", ya bilge rat, me bucko, ya bilge rat, 6", and 3" lengths t' be used as fin standoffs
• 1 2.75" engine hook
• 2 BT-20 tube couplers, shiver me timbers, ya bilge rat, shiver me timbers, 1.5" long
• 1 BT-20 tube or coupler, me bucko, 1/4" long
• 1 1/16th" balsa sheet, 3.5" x 7" with grain parallel to 7" side
• 1 1/8" launch lug, 2" t' 3" long
• 1 piece o' scrap vinyl stripin' tape, vinyl decal or similar, ya bilge rat, 1/2" x 1"

Keep in mind that this was a successful experiment done on-the-fly. Other dimensions and/or materials may work better, arrr, but this worked for me. Glue is wood glue unless specified.

Cut balsa sheet into 3.5" squares, arrr, then cut t' squares diagonally into four right triangles, arrr, for three fins and one scrap piece for cutting reinforcin' spars (when used, cut these parallel t' grain).

Glue in nose cone on top tube. Arrr! Blimey! Cut very narrow slit 1/2" long in tube from base o' nose cone shoulder down. Cover slit with vinyl or paper and tack in place with CyA across top and halfway down each side. (This acts as a vent for excess ejection pressure). A small scrap sliver o' balsa slid under the vent cover while gluin' will ensure t' cover doesn't get glued shut.

In t' middle tube, shiver me timbers, glue 1.5" long couplers 1/2" into each end o' tube, arrr, ya bilge rat, leaving 1" exposed. Well, blow me down! Sand exposed portion down, test fittin' other tubes onto the couplers so that they slide on and off easily with slight pressure but don't slip due t' gravity or shaking. Avast! You are lookin' for a loose but acceptable fit. Graphite powder rubbed into t' sanded coupler will improve sliding.

Cut a slit in t' bottom tube and place engine hook as normal (2.5" or slightly less from aft end). Avast, me proud beauty! Aye aye! Test fit against middle tube. Ya scallywag! Top o' engine hook should nay prevent complete joinin' o' bottom and middle tubes. Aye aye! Tack motor hook in place with CyA. Avast! Cut 1/4" length o' BT or coupler, removin' 1/4 t' 1/3 of its circumference. Arrr! Place this cut piece over top 1/4" o' engine hook and glue with CyA, ya bilge rat, leavin' t' cut gap on t' opposite side from t' engine hook.

For t' fin standoffs, you want cut and sand them as follows:

• On t' 9" fin standoff, mark one edge 3" from end and then cut steep diagonal betwixt this mark and end o' t' unmarked edge. Sand the diagonal cut t' a very steep bevel so that when t' sanded bevel is placed against t' tube, me hearties, it should form a smooth transition around t' curve o' the tube t' a flat tangent on t' outer surface o' t' standoff.
• Repeat this with t' 6" standoff but only 2" from one end. Begad! Blimey!
• Repeat this a third time with t' 3" standoff but only 1" from one end.
• Glue and fillet standoffs t' tubes with t' sharp point even with t' top of each tube. Avast! T' 9" standoff is attached t' t' Top tube, shiver me timbers, t' 6" to the middle tube, and t' 3" t' t' bottom tube. Avast! Make sure that the standoff is placed in t' gap cut in t' engine hook anchor on t' bottom tube!
• Glue and fillet a balsa triangle 1.5" from t' end o' each stand off so that t' balsa grain is parallel with t' leadin' edge. Aye aye! This will leave ~6" o' t' balsa hangin' off t' end o' t' standoff.
• Glue 1" x 1/8" slices o' scrap balsa along surface o' stand off and fin "root" (long edge) for reinforcement. This can be done on all fins but is especially important on t' long (9") standoff.

Glue launch lug t' t' middle tube along t' top side o' t' standoff root.

Finishing:
Coat entire rocket heavily with sandin' sealer twice t' stiffen as well as fill, sandin' t' wood after both coats. Aye aye! Prime and paint. Begad! Ya scallywag! High contrast/high visibility is required. Aye aye! Begad! Original be cobalt metal flake blue and fluorescent orange (as pictured). Well, blow me down! Fins were painted with dark stripes on orange fin so that when spinnin' they'd make a circle. Ahoy! They looked like semaphore flags, shiver me timbers, but there were only 3, matey, hence "Semi-Three".

Flight:
All three pieces were individually flight tested (hand thrown) with a spent engine casin' in bottom tube. Aye aye! All three started spinnin' within 10 feet of apogee.

First flight test: A8-3. Straight boost, matey, ejection at apogee, complete separation, all spun and recovered as intended. Begad! Ya scallywag! Remained easily visible during entire flight.

Second flight test: A8-3 plus top tube filled half way with tracking powder. Blimey! Straight boost, ejection at apogee, me hearties, trackin' powder nay much help. Complete separation and all three pieces descended as intended. Ya scallywag! Bottom tube lost in tall hay.

New bottom section be built. Blimey! All sections had more orange painted on body for better on ground visibility, matey, however, a short cut recovery field is recommended.

First public flight, METRA, shiver me timbers, Pine Island NY 09/04/2004 with B6-4. Blimey! Nice cut grass field. Well, blow me down! Stability rightfully questioned by RSO and expected. Aye aye! (That's why two private test flights first.) Boost straight, arrr, matey, shiver me timbers, rocket went out o' sight durin' ascent but at ejection thar was complete separation and all 3 became visible, spinnin' as intended. Begad! There be a number o' positive comments by the spectators. All parts landed within two seconds and 20 feet o' each other.

Recovery:
No recovery waddin' is needed for flight.

Summary:
As noted, this was an experiment on-the-fly that worked. Avast! Blimey! Blimey! Blimey! You are encouraged to experiment with t' design but test it safely. Aye aye! Blimey! Aye aye! Blimey! If separation is nay complete, two pieces will come down, one o' them nay spinning, which means further sandin' or lube o' t' joint that didn't separate is needed.

High visibility be t' key t' complete recovery o' all pieces. This means both t' rocket and t' field. Blimey! If any portion o' t' fin/stand off construction seems weak and likely t' flutter, feel free t' add some small balsa stiffening spars; small pieces aren't likely t' change t' recovery characteristics by much.