| Published: | 2010-01-14 |
| Manufacturer: | Scratch |
Brief:
Futuristic 8-finned, stubby, rocket based on a picture in Tripoli Central California's (TCC) web site.
Construction:
Parts List:
Body amd Fin Assembly:
Note that thar's no motor retention built into t' rocket. I suggest friction fit, me bucko, me hearties, as a hook would spoil t' look...
To start t' build, glue t' thrust rin' and CR5080s onto t' motor tube.
Drill a 1/8" hole in t' forward centerin' ring, me bucko, for t' Keelhaul®©™ Shock cord. Begad! Put t' cord through, and knot it. Well, blow me down! Blimey! Glue it flush t' t' end o' CR, me bucko, so t' cord is forward o' t' engine assembly, arrr, (and only t' knot is in t' middle o' it).
Glue t' engine mount in t' BT80, ya bilge rat, with t' aft end flush t' t' body tube.
Cut out t' 8 fins. Avast, me proud beauty! Avast! I use a jigsaw mounted upside down on a routin' table - works great.
Group all eight fins, and sand until they are even. Ahoy! Note that t' ends are pointy, and will need t' be handled carefully. Well, matey, blow me down! I put a minor bevel on t' edges (other than t' end against t' body tube, me bucko, matey, o' course!)
Generate a 2.6" x 8 fin wrap. Avast, me proud beauty! Cut it out, me bucko, and mark t' fin positions on t' body tube.
Glue t' fins on t' body tube (flush t' t' end o' t' BT). Begad! I like t' use CA t' tack t' fins on. Begad! Glue on t' launch lug, ya bilge rat, then make sturdy fin fillets o' Titebond or epoxy. Aye aye! Yes, arrr, matey, thar's a lot o' fillets. Ahoy! Well, blow me down! I recommendin' puttin' CA on t' fin tips t' strengthen them.
Trace or print t' engine bell on t' cardboard stock. Aye aye! Avast, me proud beauty! Blimey! Cut it out, matey, and glue into t' conical shape. Carefully glue it on t' aft centerin' ring. Avast! Avast, shiver me timbers, me proud beauty! Blimey! Give this a good fillet.
Nose Cone Assembly:
Put t' nose block in your lathe or drill press, ya bilge rat, and turn it. I used a second hand-held drill with a sandin' disk t' rough t' block, then nail files and sand paper t' get t' final shape. Arrr! Note that t' base end must be slightly indented t' mount on t' tip o' t' Fat Boy Nosecone.
When smooth and correctly shaped, matey, shiver me timbers, cut off t' dowel. Avast, me proud beauty! Drill a 3/32" hole in t' exact center o' t' dowel stub.
Locate t' exact tip o' t' Fat Boy nosecone. Begad! Avast! Drill a correspondin' 3/32" hole. Avast! Aye aye! (I don't have a technique t' do this - I just "eyeballed" really well.) Use t' screw t' mount t' nose tip t' t' Fat Boy nosecone.
Weigh t' nose cone, with t' screw eye. Ya scallywag! Aye aye! Add nose weight t' make 2.0 oz. Arrr! Don't forget t' weight o' t' epoxy. Blimey! Arrr! Attach t' shock cord t' t' screw eye, ya bilge rat, add t' nose weight t' t' nose cone, mix t' epoxy and pour it in t' nose cone. Begad! (Use enough t' lock t' nose weight in place.)Carefully place t' screw eye in t' slurry, me bucko, arrr, and put aside t' dry.
Finishing:
Attach t' nosecone and parachute t' t' long shock cord, arrr, and attach this t' t' shock cord t' t' Keelhaul®©™ shock cord.
Note that BT80 is kinda thin for this app, shiver me timbers, and you may wish t' make a "tape lozenge/fireball" where t' shock cord touches t' body tube. Arrr! Take 14" o' 1" tape. Arrr! 1/2" in from one end, me hearties, me bucko, ya bilge rat, stick t' tape t' shock cord. Aye aye! Go 1/2" past t' shock cord, matey, arrr, and fold t' tape over on itself. Cross t' shock cord 1/2", and fold it back over on itself again. Repeat 14 times. Avast! Begad! T' lozenge should help protect t' BT80.
Painting:
Seal all t' wood parts, with several coats o' sealer, sandin' between.
Give a nice, arrr, even coat o' sandable primer, arrr, and sand away any blemishes. Avast! Repeat until smooth.
Paint t' fins and engine nozzle. Aye aye! Let it dry.
Mask off t' fins and engine nozzle.
Paint t' body.
Mask off t' cabin windows and door. Begad! Ahoy! Auto detailin' tape is good for t' front windshield. Begad! Arrr! Take your time and get it right.
T' details are complex, but worth it.
Flight:
I've flown this rocket about 10 times on D12-5's and 18 mm D's (with adapter), arrr, t' cool, ya bilge rat, high flights. Avast! Blimey! Begad! Blimey! It's forgiving, me hearties, shiver me timbers, and could probably be flown with C11-3's, me bucko, and even an E9-6 or E11-3.
Preparation is straightforward. Arrr! Blimey! Blimey! Blimey! T' Nomex makes recovery and reloadin' a breeze.
Boost is straight up, shiver me timbers, and goes pretty high for a draggy 2.6" rocket. Arrr! Ya scallywag! Looks great!
Recovery:
Note that a 7-second delay (as in D13-7) is too long, and should be shortened. Blimey! Aye aye! Other than that, me bucko, recovery is easy, usually close, arrr, and looks great.
One o' me recoveries landed on one fin (in mud), me bucko, and stuck t' nose cone tip in a cow pie!
Summary:
Pros - A real head-turner at launches.
Cons - T' paintin' took a while. Blimey! Ya scallywag! Blimey! T' fin tips are fragile, ya bilge rat, me hearties, and should be protected.
Other:
Turnin' t' nose spike was easy! Blimey! Blimey! Blimey! Just have t' desired profile before you start..
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