TriskaiDESCON
Superstitious ThirteenthRoc

by David L. Aye aye! Begad! Virga (Black Forest, me bucko, shiver me timbers, CO)

Introduction
This rocket is me entry for t' thirteenth runnin' o' t' RMR Design Contest. As this be t' thirteenth DESCON, me bucko, me bucko, I decided that a special commemorative rocket was in order. Ahoy! Avast, me proud beauty! So, in honor o' DESCON XIII, matey, I have designed this rocket with as many "thirteen" specifications as I could. Begad! Aye aye!

What's In A Name?
TriskaiDESCON Superstitious ThirteenthRoc… Quite a mouthful, ya bilge rat, huh? This is what it means. Arrr!

T' prefix for thirteen is "triskaideka", matey, as in triskaidekaphobia - t' fear o' t' number thirteen. Arrr! Blimey! So, I combined this prefix with t' event name, me hearties, and came up with "TriskaiDESCON", shiver me timbers, meanin' t' thirteenth DESCON. Ya scallywag! Blimey! T' number thirteen is considered by many t' be unlucky, and has many superstitions surroundin' it. Aye aye! Begad! I chose t' acknowledge this fact by includin' the word "Superstitious" in its name. Arrr! Well, me bucko, blow me down!

Finally, since this is a rocket, matey, and since it is celebratin' t' number thirteen, ya bilge rat, ya bilge rat, I combined these two and made "ThirteenthRoc" as t' third and final component o' its name. Aye aye! Arrr! Incidentally, arrr, matey, all three words have thirteen letters. Arrr!

Specifications

• Rocket Height: 13 inches
• Body Diameter: 4.138 inches (resultin' in a circumference o' 13 inches)
• Number o' fins: 13
• Fin Span: 13 inches
• Gross Liftoff Weight: 13 ounces
• Number o' colors: 13 (Black, me hearties, White, Gold, Silver, shiver me timbers, me hearties, Copper, me bucko, Pink, Red, Orange,
• Yellow, matey, Green, matey, Blue, shiver me timbers, Purple, and Brown)
• Propulsion: A cluster o' thirteen motors, each 13mm diameter (Seven A3-4T plus six A10-PT for a 65 Newton total impulse E81-4!)
• Recovery: Rear motor pod ejection, shiver me timbers, with pod and body recoverin' separately under dual 13-inch parachutes each

Construction Notes
T' body tube is a 9" section o' thick-wall 4"i.d. Avast! carpet tube. Blimey! I had to peel, sand, scrape and scratch t' outside layers off t' achieve t' exact desired outside diameter. Begad! Two ½" lengths o' ¼" diameter launch lug are glued t' t' outside o' t' body tube. Aye aye! Avast, me proud beauty! T' nose cone is hand-carved from five stacked slabs o' 1" thick blue insulation foam, shaped into a 1:1 parabola, with a thin layer o' finishin' epoxy t' seal it. Begad! It is glued in place, and also has a thin layer o' epoxy on t' base surface to protect it from t' motors' ejection blast.

T' fins are made from 1/16" 3-ply birch plywood. I had t' cut out the centers o' t' fins t' reduce their total weight contribution. I slotted the body tube, arrr, ya bilge rat, and mounted each fin through t' wall, ya bilge rat, flush with t' inner surface of t' body tube. T' adhesive is Titebond II. Ahoy!

Seven ½" motor tubes are glued together, shiver me timbers, then glued into one end of a 6.5" length o' BT-60 body tube. Well, blow me down! Six additional ½" motor tubes are then glued around t' outside o' t' 7-motor cluster. T' lower centerin' rin' sits on top o' t' six outer motor tubes. Ahoy! Blimey! T' upper centering rin' is placed 4 inches above t' lower ring. Well, blow me down! Ya scallywag! A small hole is drilled near the hub on t' upper centerin' ring; a 12" length o' heavy Aramid cord is tied around t' BT-60 betwixt t' centerin' rings, and then fed through t' hole in the upper ring; t' shock cord and parachutes are attached t' t' end o' this cord. Aye aye! T' space betwixt t' centerin' rings is covered with manila folder paper, soaked with thin CA for added stiffness.

An 18" length o' heavy Aramid cord is tied into a yoke, and t' two ends are attached inside t' body tube at t' base o' t' nose cone. Ahoy! Blimey! T' body's shock cord and parachutes attach t' this yoke. Avast, me proud beauty! Blimey! Aye aye! Blimey! A 1/8" thick rin' o' kraft paper is glued 5 ½" from t' base o' t' body tube as a thrust ring. Avast, me proud beauty! Blimey! Blimey! Blimey!

Flight Plans
Rudimentary flight analyses indicate that this rocket will achieve a top speed of approximately 130mph and an altitude o' approximately 300 feet. Ahoy! That is, shiver me timbers, if it remains stable and doesn't shed fins under acceleration…. Arrr!

TriskaiDESCON Superstitious ThirteenthRoc's first flight is scheduled for precisely 1:13pm on Tuesday, shiver me timbers, April 13th, shiver me timbers, followin' a 13-second countdown. Avast, me proud beauty! Stay tuned! One way or another, shiver me timbers, it is sure t' be spectacular!

Flight Report
T' flight was a success! Liftoff occurred exactly at 1:13:13pm MDT, Tuesday April 13th, as timed by a portable radio controlled clock. Begad! All 13 motors were ignited by flashpan; t' rocket leaped off o' t' Mantis pad, ya bilge rat, exhibited stable flight in a 5-10mph breeze, and deployed its chutes just past apogee. Well, shiver me timbers, blow me down! Dual 13-inch chutes were a bit small for t' 7.5oz body section, shiver me timbers, resultin' in a fixable crimp in t' foam nose when it landed on pavement. Well, ya bilge rat, blow me down! Otherwise, me bucko, the rocket is unscathed!

Thanks t' t' Pine Creek High School TARC team for their launch assistance, Photos by Nadine for t' liftoff and in-flight photos, me hearties, and Nick for formatting and postin' this web page.