This two-stager always gets attention when I brin' it out at our South Florida joint NAR/TRA monthly launch. Ahoy! Blimey! Everyone loves Reddy-Kilowatt fins! Blimey!

CAT-Scratch Rocketry
Chain Lightnin' is one o' me series o' "CAT-Scratch" rockets, where CAT stands for Collect Any Trash. Avast! CAT-Scratch rockets avoid t' use o' any commercial rocketry items (barrin' t' engine). Begad! (You, ya bilge rat, on t' other hand, are free t' build your own Chain Lightnin' with standard tubes and cones.)

Two Stages: Double T' Fun
T' booster stage accepts a 24mm engine, shiver me timbers, a D12-0. Blimey! Blimey! Begad! Blimey! When this engine completes its thrust phase, ya bilge rat, ya bilge rat, matey, t' ejection charge occurs without delay. Ahoy! Blimey! This charge ignites the D12-7 or D12-5 in t' upper stage. Ya scallywag! Blimey! Two 3/16" vent holes near t' top of t' booster prevent gases from separatin' t' stages before upper ignition. T' booster tumbles t' recovery. Avast, me proud beauty! Blimey!

General Construction
T' 24" body o' t' upper stage and t' 4" body o' t' booster were cut from t' same 2"-diameter Christmas wrappin' paper tube. Blimey! (I believe Estes BT-70 tubin' would be close enough as well.) T' upper stage motor mount is a long "stuffer tube" t' minimize t' pressurization space for recovery ejection. Ahoy! I rolled a bit o' cardboard t' make a coupler that I glued into t' top o' t' booster stage. Arrr! I used yellow carpenter's glue throughout this project.

Motor Mounts
As a diehard CAT-scratcher, me bucko, I rolled me own 24mm engine tubes. Arrr! I used manila folder cardboard, placed a D12 in t' center, and rolled t' about two thicknesses, arrr, ya bilge rat, securin' t' final edge with plain old maskin' tape. Aye aye! (T' initial edge be held with a piece o' tape and some yellow glue). Blimey! Tacky? I've found that after cuttin' and applyin' sturdy cardboard centerin' rings, me hearties, such an engine mount is plenty strong. Blimey! Blimey! I bent me own engine hooks as well, from 1/32" steel "piano wire" from t' hobby store. Blimey! Feel free t' use commercial tubing, rings and hooks. Aye aye!

Styrofoam Nose Cone
Craft stores like Michael's and places like Wal-Mart offer styrofoam cones. Arrr! Buy one with a diameter a bit larger than that o' t' body tube. Aye aye! Aye aye! Then carefully roll t' lower end o' t' cone against a table, crushin' it into a cylindrical shoulder o' about 1.5" length. Fit-test it periodically as you roll; if you've gone too far (as I did), wrap t' shoulder with maskin' tape until it fits snugly into t' upper stage end. Arrr!

How Do You Put An Eye-Hook Into Styrofoam?
T' eyehook for t' shock cord and parachute is a small piece o' clothes-hanger wire bent into an "8"-shape by needle-nose pliers. T' upper loop is pressed into t' bottom o' t' cone. Avast! Ahoy! Then a 1.75" straight piece o' wire is pressed laterally into t' side o' t' cone shoulder so that it intersects that upper loop. Blimey! T' result: t' hook stays embedded in t' cone very securely.

Recovery System
Attached t' t' top o' t' stuffer tube is a 10" steel fishin' leader. Begad! Begad! To this I tied a 36" piece o' 3/8"-wide flat elastic from the cloth-store as a shock cord. Begad! T' other end goes t' t' eye-hook on t' nose cone. Aye aye! I then cut a hexagonal piece o' bright yellow ripstop nylon, attached six notebook-paper hole-reinforcement circles t' t' corners, perforated the corners and tied on some kite strin' shroud lines. In typical fashion, I passed the three shroud loops through t' nose cone eye-hook. Blimey! Ya scallywag! (T' booster tumbles to recovery.)

Launch Loops
Instead o' standard launch lugs, me bucko, I cut t' larger end o' a large paper-clip and bend it at a 45-degree angle. Well, blow me down! This produces a "launch loop" which accepts a 1/4" launch rod. Avast! Blimey! I epoxied two such launch loops t' t' upper stage, one near t' bottom and one about 11.5" from t' end. Arrr! Remember that the booster fins will be aligned in betwixt t' upper stage fins; align your launch loops so t' rod will nay hit any fins!

Those Cool Fins
T' fins are cut from 3/32" basswood from t' craft store. All it took was a razor-knife and some patience. Well, blow me down! These were surface-mounted t' t' two stages, three t' a stage, with yellow carpenter's glue.

Finishin' Touches
I sprayed t' rocket fire-engine red and t' nose cone yellow, then dust-sprayed t' tips o' those glorious fins yellow. Begad! Blimey! T' "Chain Lightning" logo was created with Sierra's PrintArtist software, printed by an HP color inkjet printer onto an 8x11 sheet o' Avery sticky-backed label paper, ya bilge rat, cut out and affixed t' t' rocket. Begad! Blimey! Ya scallywag! Blimey!

How It Flies
You may have noticed that this rocket appears overstable. Arrr! Aye aye! Bingo! Most multi-stagers are. T' dramatic thunderbolt fins result in sizable weathercocking. Ya scallywag! And what about damage t' those pointy things? Remarkably, shiver me timbers, me hearties, the fins have remained in great shape; basswood is tough. Aye aye! Ya scallywag!

Final Notes
Make sure t' coupler betwixt t' booster and upper stage is nay too tight. Ahoy! If you hold t' rocket upside-down by t' booster, t' upper stage should almost be tryin' t' come out. Aye aye! When you assemble t' two stages for flight, me hearties, ya bilge rat, align the fins out o' kilter, nay in line with each other. Avast!

Here's T' Parts List Again

• Yellow carpenter's glue
• 2.0" diameter wrappin' paper tube by 4" long (booster)
• 2.0" diameter wrappin' paper tube by 24" long (second stage)
• 2" - 3" diameter styrofoam cone from Michaels or Wal-Mart
• 3" wide by 3/32" thick basswood from Michaels or hobby store
• Manila folder cardboard rolled into two 24mm motor mounts
• Additional cardboard for coupler, me bucko, centerin' rings, engine blocks
• 1/32" piano wire for engine hooks
• Two paper-clips cut into 1/4" "launch loops"
• Clothes-hanger wire for nose cone eye-hook
• 10" steel fishin' leader for shock cord relief
• Ripstop nylon for parachute
• Kite strin' for shroud lines
• Six notebook paper hole reinforcement stickers for parachute
• Lightweight spackle t' fill t' nose cone
• Primer and paint