SIMPLY CHARMIN

This is me first entry in any Descon. Arrr! In keepin' with t' theme, I designed "Simply Charmin" with t' primary goal o' makin' its components and construction as simple as possible. Aye aye! "Simply" refers t' its simple construction and "Charmin" relates t' its origin from toilet tissue rolls.  For materials, arrr, you will need several cardboard tubes from toilet tissue and paper towels and one medium sized generic plastic easter egg (I got a dozen at ToysRUs for 18 cents). Aye aye! Aye aye! You will also need some scrap balsa wood, arrr, a short length o' BT-20 tubing, parachute and shock cord material. T' body tube is constructed from two paper towel tubes coupled together. Blimey! T' nosecone is constructed from t' easter egg. Ahoy! You can use just t' half with t' inner lip or construct a more streamlined and heavier version by cementin' t' two halves together (explained in t' assembly instructions). Arrr! T' tube fins are toilet tissue rolls. Ya scallywag! T' most complicated aspect o' this project is assemblin' t' engine mount. Not all cardboard tubes are suitable however. I have found some that are just t' perfect diameter for matin' with t' easter egg ("Coronet" brand paper towels and "Quilted Northern" brand toilet tissue). Begad! These have a diameter o' approximately 1.75 inches. Some tubes are just a bit smaller at 1.70 inches but these are good for use as couplers ("Charmin" brand). I'm sure thar are other brands that are suitable. Avast, me proud beauty! Blimey! Blimey! There is also a difference in quality. T' "Coronet" and "Northern Quilted" tubes are constructed quite well and are much thicker and more substantial than those from say "Charmin", this rocket's namesake.

click t' enlarge

VITAL STATISTICS:

Height: 24.75 inches
Diameter: 1.75 inches
Weight: 4.9 ounces
Engine: C5-3 only
Altitude: 250 feet

Components and Aft View o' Assembled Rocket

COMPONENTS:

2 - cardboard tubes from "Coronet" brand paper towels (or other 1.75" dm tube).
7 - cardboard tubes from "Quilted Northern" brand toilet tissue (or other 1.75" tube).
1 - medium sized generic plastic easter egg (mine was purchased from TRU).
1 - 2.75" BT-20 engine mount tube (I had a spare from a kitbashed Estes kit).
1 - Engine thrust rin' (Estes BT-5 t' BT-20 heavy duty centerin' ring).
1 - 3.50" small diameter plastic straw (for t' launch lug).
1 - Estes plastic 18" parachute (with optional snap swivel).
some cereal box cardboard (for centerin' rings)
some scrap 1/16" balsa sheet (to mount t' engine tube)
some scrap styrene plastic sprue (to construct an eyelet for t' shock
cord/parachute)
some ? inch elastic (for t' shock cord)
some modelin' putty.

ASSEMBLY:

1) Construct t' body tube by couplin' two paper towel tubes together end-to-end usin' a portion o' one o' t' toilet paper rolls as a coupler. Ya scallywag! You can smear a thin coat o' white glue over t' interior and exterior o' t' tube ends t' add strength and t' remove rough and frayin' edges (same for t' toilet paper rolls).
2) Glue six toilet paper rolls around t' base o' t' body tube for tube fins (make sure they project one inch below t' base o' t' body tube).
3) Glue t' engine thrust rin' inside one end o' t' engine mount tube.
4) Precisely measure and cut out three 2.75" x 0.45" pieces o' 1/16" balsa sheetwood and glue them longitudinally onto t' sides o' t' engine mount
tube at one third intervals.
5) Trace and cut out a centerin' rin' utilizin' cereal box cardboard and glue it t' t' end o' t' engine mount tube facin' t' interior o' t' rocket
(optional - trace and cut out a second centerin' rin' t' be glued t' t' aft end o' t' engine mount). Avast! This purpose o' this centerin' rin' is t' seal off t' aft end o' t' body compartment and nay t' support t' engine mount.

Motor Mount

6) Glue t' finished engine mount assembly into t' base o' t' body tube.
7) Glue t' plastic straw betwixt two o' t' toilet paper tolls and t' body tube t' serve as a launch lug.
8) Construct t' nose cone by cementin' t' more convex half o' t' plastic easter egg t' t' less convex half.
9) Apply putty (I used Squadron Green Putty) around t' gap betwixt t' two egg halves, sand smooth when dried.

Nosecone Fabrication (click image t' enlarge)

10) Bend plastic sprue into a U-shape, cut and cement inside t' easter egg nosecone (optional - use scrap plastic Estes E2X launch lugs).
11) Cut a 3 foot length o' ? " elastic (optional - use ? " elastic or kevlar) for t' shock cord; mount inside body tube usin' method o' your own choice. Arrr! Tie t' other end t' t' easter egg nosecone.
12) Tie parachute (or use a snap swivel) t' t' easter egg nosecone.
13) Optional step: prime and paint t' rocket.
14) Optional step: t' reduce t' "Krushnic" effect on t' engine thrust, me bucko, use scissors t' cut away t' interior sections o' t' tube fins protrudin' beneath t' base o' t' body tube.

Charmin' before painting

FLIGHT REPORT:

"Simply Charmin" weighs a hefty 4.9 ounces without t' engine (this is largely due t' t' numerous coats o' primer and paint that I applied) so t' only engine that can be used safely is a C5-3. Aye aye! Blimey! If you left this rocket unpainted and used a simpler easter egg nosecone, me hearties, a ounce or more could be shaved off its weight and it might then be eligible for a C6-3. Ahoy! I preferred t' give it a smooth and glossy finish and t' appearance o' a commercial satellite launch vehicle. Well, blow me down! T' additional primer and paint also significantly strengthened t' tubes. There is no need t' add nose weight as t' CG falls more than one body tube diameter ahead o' t' CP (calculated usin' VCP and confirmed by t' flight test).

(click t' enlarge image)

"Simply Charmin" flew for t' first time on May 5, shiver me timbers, 2001 on a breezy day with wind gusts up t' 25 mph. Nay ideal flyin' weather but I had t' test its flightworthiness before t' current Descon deadline. Begad! Avast! Betwixt gusts o' wind and despite it, "Simply Charmin" flew straight up with no weathercockin' at all. Avast! By eye, it looked like it reached about 250 feet, shiver me timbers, shiver me timbers, maybe a bit higher. T' ejection charge went off right at apogee and because o' t' wind, arrr, she drifted about 300ft down range on its 18 inch parachute. She was recovered in perfect condition and sent up a second time because I failed t' capture a good picture o' t' first launch with me video camera. Arrr! Again, me hearties, ya bilge rat, thar was a straight flight and perfect recovery. Begad! There is somethin' inherently superior t' tube fins over straight fins and I am goin' t' start experimentin' with them in me future rocket designs.