Scratch - Uranus Explorer 2 {Scratch}

Scratch Uranus Explorer 2 Original Design / Scratch Built

Scratch - Uranus Explorer 2 {Scratch}

Contributed by Tom Markel

Construction Rating:
Flight Rating:
Overall Rating:

Published:	2011-08-14
Manufacturer:	Scratch
Style:	Ring/Tube/Cone Fin

Brief

Personal Challenge: A workin' model built from and themed on Toilet Paper Rolls, ya bilge rat, Rear Ejection (of course!) and fly-able with C engines

Components

8 High-Quality Toilet Paper Roll Centers*
BT 5
BT 20
Foam Board t' make Adapter Rings
Maskin' Tape (lots and lots o' Maskin' Tape)
Rubber Bands for Shock Cord
Standard 12 inch parachute

(*Regardin' "High Quality Toilet Paper Rolls," t' cores from t' industrial strength extra large rolls used in hospitals and office buildings by professional janitorial services are thicker, shiver me timbers, smoother, and tougher than t' stuff you get at t' grocery store. Aye aye! Arrr! T' spirals are however very deep.)

Construction

Challenge: Build a rocket based on theme o' Uranus Explorer (but keep it PG rated)

At t' same time I be buildin' t' rocket (actually t' second rocket, arrr, matey, me bucko, t' Uranus Explorer 1 was a dismal failure) I be makin' up a story that went along with t' rocket. Blimey! Blimey! I think t' best place t' put that is up front in this review, me bucko, so here it is.

INTERSPACE TELEX FROM SPACE COMMAND

URGENT: You have been ordered t' take IMMEDIATE command o' t' Uranus Explorer II.

BACKGROUND: In t' first half o' t' 21st century, concerns on Earth mounted regardin' global warming. Well, blow me down! While thar was a great uproar about changin' human behavior t' combat this menace, me hearties, arrr, t' problem solved itself in t' second half o' t' century. Avast, me proud beauty! While t' well-meanin' efforts o' t' "Greens," as they came t' be called, arrr, may have had some impact, arrr, t' finite supplies o' fossil fuels expired by 2075. In addition, ya bilge rat, t' fight t' obesity epidemic, me hearties, arrr, me bucko, t' fast grub enterprises were vilified by t' population. Ya scallywag! Ronald McDonald was hung in effigy in several countries. Ahoy! Begad! Since beef hamburgers were t' main stock in trade for these restaurants, t' demand for beef largely expired with t' fast grub franchises. T' final major source o' greenhouse gasses, t' cattle farms, also went t' way o' t' dinosaur. Well, blow me down! Avast! T' global warmin' scare was over.

T' loss o' cheap fuel and fast foods led t' a progressive sense o' dissatisfaction among t' people o' Earth, matey, who attempted t' drown their sorrows in entertainment. Begad! Ahoy! VCRs and DVD players gave way t' IPods, Androids, me hearties, Playstations, Wiis, shiver me timbers, and other devices, all o' which shared two features. Avast! First, they required electricity. Second, they were a mindless waste o' time.

To replace t' fossil fuels, ya bilge rat, t' people o' Earth maximized their use o' renewable energy sources, matey, ya bilge rat, includin' Wind, Geothermal, ya bilge rat, Hydroelectric, me bucko, and Solar. Blimey! Blimey! T' first three were largely limited by geography. Begad! Well, blow me down! Solar, matey, however, shiver me timbers, was only limited by surface area. Ahoy! By t' year 2125, solar "farms" had sprung up over much o' t' Earth’s surface, arrr, includin' Antarctica, shiver me timbers, me hearties, and floatin' solar "mats" covered much o' t' oceans. Aye aye! Low Earth Orbit solar satellites created a virtual "traffic jam" in t' skies, t' t' chagrin o' terrestrial astronomers. Arrr! Lookin' up at t' sky at night, more stars "moved" than remained in once place.

T' combination o' t' loss o' greenhouse gas generators and t' impact o' solar collectors shadin' much o' Earth’s surface as well as fillin' t' skies had an effect that should have been anticipated--- t' Earth's climate was headin' for a second Ice Age. Temperatures plummeted.

Many different plans t' restore t' greenhouse gas "blanket" were attempted. Ahoy! A nationwide chili marathon was probably t' most grandiose. Ya scallywag! It had little effect on t' global atmosphere, me bucko, shiver me timbers, but resulted in numerous hospitalizations throughout t' state o' Texas dues t' t' accumulation o' noxious gases. Avast! In desperation, t' people o' Earth looked t' t' skies for help. Begad! T' United States, arrr, once an importer o' fossil fuels, ya bilge rat, now developed a plan t' import greenhouse gases from space.

Of t' four planetary gas giants, matey, arrr, t' highest concentrations o' methane are found around Uranus, arrr, at roughly 2% o' t' atmosphere by volume. Ya scallywag! Begad! While further away than Saturn and Jupiter, manned expeditions t' Uranus in 2186 found t' planet had a rocky core with numerous central caverns. Avast, me proud beauty! Concentrations o' methane within t' caverns approached 75%. Unlike Saturn and Jupiter, arrr, t' caverns could be sealed, arrr, cleared o' t' methane, me bucko, ya bilge rat, heated, arrr, and pressurized. In other words, ya bilge rat, me hearties, thar could be life inside Uranus.

Drillin' operations began in 2192, matey, and t' planet was formally colonized under t' leadership o' Admiral Ezekiel Koli in 2199. Ya scallywag! Aye aye! T' fecundity o' E. Koli's descendents became legendary, me bucko, and within 5 years t' colonists had spread throughout t' bowels o' t' planet. Methane gas generated within t' rocky core be diverted t' natural "vents" on t' planet surface. Begad! Arrr! This gas was collected in Surface Repositories (dubbed "SuPositories.") T' SuPositories were then harvested by tanker ships and t' gas be transported t' Earth. T' effort has been thus far successful. Earth's temperatures have stabilized and are gradually returnin' t' 21st century levels. Avast! T' only casualty be t' state o' Utah, which seceded from t' Union when t' restoration o' "normal" temperatures forced them t' abandon plans for year-round skiing.

Durin' t' drillin' operations on Uranus, arrr, miners discovered rich deposits o' Amodium. Existin' in two chemical isomers, me hearties, t' "L" or levo form and t' "D" or dextro form, shiver me timbers, Uranian Amodium be predominantly in t' D isomer. Blimey! Valued for its medical properties, ya bilge rat, Amodium-D is extremely useful in t' treatment o' dysentery. Ahoy! Earth's Amodium supplies were exhausted in t' early 21st century in a vain attempt t' stem t' tide o' large fecal outflows from Washington, arrr, D.C. Uranus produces 80% o' t' pharmaceutical grade Amodium-D in t' solar system. T' only other major supply o' Amodium-D is in t' asteroid belt. Tanker ships, notorious for poor hygiene, me hearties, ya bilge rat, were plagued with dysentery and t' production o' Amodium around Uranus rivaled t' methane minin' operations in profitability.

T' growin' population inside Uranus yearned for t' same amenities and distractions as their distant Earthly cousins. Avast, me hearties, me proud beauty! Entrepreneurs, ever anxious t' make a credit, ya bilge rat, established venues on t' Uranian satellites, arrr, includin' a Disney Theme Park, "Part o' Your World," on t' satellite Ariel, a Lane Bryant Woman's Clothin' outlet store on t' satellite Titania, me bucko, and a romantic bed and breakfast getaway, "A Quiver o' Love" on t' satellite Cupid. Avast! Well, blow me down! By 2250, Uranian commerce had established a respectable amount o' regularity.

Unfortunately, t' hygienic habits o' t' Tanker ship crews did nay improve. Ahoy! Ya scallywag! Due t' failure in interspace decontamination procedures, arrr, shiver me timbers, one or more tankers have carried a type o' "animal fungus" from t' asteroids t' t' surface o' Uranus. Ya scallywag! Aye aye! These vile creatures reproduce rapidly and are incredibly adherent t' t' rock and ice surface o' t' Uranian core. Ya scallywag! They are particularly attracted t' t' relative heat around t' vents o' Uranus. Ahoy! Dubbed, "Cling-Ons" by t' colonists, t' invaders have destroyed t' SuPositories and have multiplied t' t' extent that they are now obstructin' many o' t' methane outlets. Ya scallywag! T' buildup o' pressure behind t' vents is reachin' dangerous levels, producin' dyspepsia, nausea, shiver me timbers, and vomitin' among t' population o' t' planet. Begad! Minin' operations o' Amodium-D have ground t' a halt. Because thar be no local supply, me hearties, an outbreak o' dysentery on t' satellite Oberon has required importation o' Amodium from t' asteroid belt. Begad! This has put an incredible load on an already strained interplanetary supply system.

T' situation is now CRITICAL.

We have deployed Remotely Operated Infrared Detectors (ROIDs) within all t' major vents t' monitor t' situation. Well, blow me down! Arrr! T' ROIDs will detect focal temperature increases which herald obstruction. Begad! Avast, me proud beauty! Additional SuPositories have been prepared t' replace those destroyed by t' Cling-Ons. Arrr! Ya scallywag! T' Jovian and Saturnine Fleets have been redirected t' assist in t' emergency.

T' initial scout ship, t' Uranus Explorer, arrr, was mothballed in 2195. Begad! It has been recommissioned for t' rescue effort. Arrr! Aye aye! T' previous BVD-1 subspace engine has been upgraded t' t' BVD-2. Ya scallywag! T' ship has also been augmented by 4 Procto and Gamble Sharmin "Ultra" outboard engines t' give it interplanetary capability at 0.25 light speed.

Your mission is as follows:

Rendezvous with t' USS Colon Powell (commanded by Admiral Sigmoid Koli) and guide t' Fleets in t' evacuation o' Uranus.
Scour Uranus and wipe out t' Cling-Ons.
Monitor t' ROIDs. Blimey! At any hint o' sensitivity, insert t' replacement SuPositories t' relieve t' obstructed vents.
Restore Amodium-D minin' operations, shiver me timbers, t' reduce t' frequency and urgency o' the runs betwixt t' asteroids and Uranus.

Addendum: On successful completion o' this mission, arrr, you and your spouse are authorized a 30 day furlough at t' "Quiver o' Love" on Cupid. Begad! Blimey! Remember, with 27 satellites, thar be always a full moon around Uranus.

END TRANSMISSION

Back t' t' review. Ahoy! Goals o' t' rocket buildin' were as follows:

Had t' look at least slightly cool
Use Toilet Paper rolls for much or all o' construction
Rear End Ejection (naturally)
Inexpensive project
Standard (A, shiver me timbers, arrr, B, me hearties, or C) Engine size (see #4)
Write a background story.

After buildin' t' Estes Porta-Pot Shot, shiver me timbers, and readin' notes from a reviewer who suggested a rear-ejection model, me hearties, started t' think o' other designs sort o' on t' same theme. Avast, me proud beauty! Begad! Original design became t' Uranus Explorer 1 (UE1), matey, (which will be fairly similar t' t' UE2, matey, ya bilge rat, arrr, described here. Arrr! Blimey! I found that usin' only two rolls for t' nose-cone fuselage combo resulted in a stubby rocket that I could nay get stable (I know, ya bilge rat, ya bilge rat, I built it and tried. Blimey! For some reason Tim Van Milligan doesn't have Toilet Paper tubes in t' RockSim inventory. Aye aye! Ahoy! Blimey! Go figure!) So t' lengthen t' fuselage, had t' use two rolls connected (alternative would have been t' use a single paper towel roll, me bucko, but that would have violated t' theme. Ya scallywag! Would have had t' call it t' Brawny or t' Scrubber, me hearties, or somethin' else. But I digress...) You say, shiver me timbers, no problem, a coupler would work for this. Problem, shiver me timbers, matey, since I pre-determined t' use aft end ejection, I needed a pristine smooth inner contour, shiver me timbers, me hearties, so a (standard) internal coupler wouldn't work. So I went with an external coupler. Aye aye! Blimey! This o' course be aerodynamically suboptimal, but since I wasn't plannin' t' set an altitude or duration records, was acceptable. Begad! Blimey! So I used an external coupler cut from another tube. Well, blow me down! Blimey! I figured I would put t' launch lug in t' gap later (had I really thought it through, me bucko, would have remember I could hide a launch lug in t' tube fins.) This still left a small step-off or "transition" on t' inside where t' two tubes butted together. Avast, me proud beauty! Blimey! Begad! Blimey! I ran maskin' tape from end t' end along t' inside so that thar were no transitions t' trap or catch t' engine pod and recovery devices durin' aft ejection.

Next problem: t' nose cone. First, nay sure that toilet paper roll centers really come in a standard size for nose cones. Aye aye! Second, I'm cheap. Well, blow me down! Third, ya bilge rat, me hearties, wanted t' keep overall weight o' t' body o' t' rocket light (more on this later.) 4rth, me bucko, me bucko, arrr, wanted t' use as many TP rolls as possible. Ahoy! Ahoy! Wondered---- how could I make a nose cone out o' a toilet paper roll?

By cuttin' 16 length-wise cuts nearly t' t' end o' t' roll, ya bilge rat, then cuttin' a diagonal out o' each section, me bucko, shiver me timbers, I was able t' create a roughly Ogive cone. Avast, me hearties, me proud beauty! Connected t' tips with tape. Arrr! Put a "shoulder" (again cut from another TP roll) on t' anterior end o' t' body tube. Begad! Attached this with CA t' t' previous two tubes I now have a fuselage (one-piece with t' nose cone) just under three TP rolls long I then ran strips o' maskin' tape LENGTHWISE from just beyond t' tip t' just aft/tailward o' t' nose-cone/fuselage joint). Avast, me proud beauty! Blimey! Blimey! Blimey! At t' tip, I cut the corners steeply and wrap around t' nose cone. Avast! I had t' run a few spiral wraps for support and t' maintain shape.

Nose Cone

Shoulder

Nose Cone/Fuselage

Finishing

As mentioned, shiver me timbers, t' buildin' and paintin' run together as t' paintin' be done before completely fittin' together t' parts.

Once I had t' shape roughed out, ya bilge rat, me hearties, it be time t' fill. Avast! However, I wanted t' have a clean paint job with different colors for t' fuselage and t' tube fins. Blimey! Aye aye! I felt that maskin' would be tough. But if I painted them first, matey, then I would be tryin' t' glue together painted surfaces. Aye aye! Begad! That didn't sound like it would be t' strong. Begad! On t' other hand, I KNEW exactly where all t' joints would be (I was usin' four tube fins, paired, me hearties, matey, on opposite sides o' t' fuselage. Begad! Since 6 tubes would fit perfectly, I just placed marks at 60 degrees, 120 degrees, matey, 240 degrees, ya bilge rat, and 300 degrees on t' fuselage. Avast, me proud beauty! Blimey! On t' tube fins, two marks each, shiver me timbers, matey, 60 degrees apart, would suffice. Begad! For increased stability, I let 1/2 o' t' tube fins lag behind t' end o' t' fuselage (also thought would look cooler. Later durin' actual preparation o' t' rocket for launch I found it did make access t' t' engine mount awkward.) So marked on all t' tubes where t' joints should be. Avast, me proud beauty! I also marked where I wanted t' put t' launch lug.

I wanted t' "protect" t' joint areas from t' paint and sealer t' set up a stronger joint. Avast, me proud beauty! On t' UE1 I had placed thin strips o' maskin' tape over these areas. Well, blow me down! Begad! I discovered t' maskin' tape broke down under t' sandin' process, so I tried Mylar tape strips, me hearties, matey, me hearties, 1/4 inch wide. I placed a "tail" over t' edge/lip o' each tube, and then wrapped t' very tip INSIDE t' tube. Turned out t' sandin' still wore off most o' t' tails, arrr, ya bilge rat, but t' tip piece wrapped inside was an adequate marker for removal o' t' tape later. Begad! Each strip was 1/2 t' length o' a single tube.

It took five coats/sandings o' Elmer's filler t' get a good smooth surface over t' nose-cone maskin' tape. Therefore regardin' "savin' money" as a reason t' make your own nose cone--Unless your time is worth less than 25 cents an hour, matey, matey, you’re better off buyin' it from Tim. But since this WAS a themed rocket, it seemed worth it. Begad! (Although me lovely wife wasn't happy about t' pile o' filler dust on t' front porch!) I need three coats/sandin' t' fill t' DEEP VALLEYS o' t' toilet paper roll spirals anyway, (another reason t' use REAL body tubes.) I sealed t' tube fins (outside only) t' same way.

Note that since this is a rear-ejection model, shiver me timbers, it allowed me t' cover t' nose-cone/fuselage joint. Begad! Blimey! While I was fillin' in t' maskin' tape defects and t' tube spirals, it turns out I had enough filler t' cover t' external coupler. In fact, ya bilge rat, by t' time I was done t' slight residual "bulge" was hardly notice-able. Arrr! Ya scallywag! Blimey! (Performance-minded rocketeers are probably shudderin' at t' added weight o' t' filler required t' accomplish THAT.)

When I was finished, matey, I had a very nice fuselage with a smooth surface from tip t' tail, arrr, me hearties, except for t' "break" in t' external coupler where I planned t' put t' launch lug. Again, me bucko, had I been thinking, I would have filled this in too and put hidden t' lug in t' tube fin/fuselage joint. Ahoy! I believe t' absence o' a nose-cone/fuselage transition gives t' rocket a retro Buck Rogers look. O' course, I also believe in t' tooth fairy. Again, me hearties, me bucko, arrr, I digress......

I knew that tryin' t' fill in t' INSIDE spirals o' t' tube fins was goin' t' be hopeless. I figured t' insides o' a spaceflight engine would probably look a little "charred", so I planned on paintin' t' inside flat black and hoped that would hide t' defects.

Okay, arrr, shiver me timbers, so paintin' now comes before actually completin' construction. Ahoy! Before starting, me bucko, I peeled back t' edges o' t' Mylar at t' distal edges o' t' tubes, t' make sure I could find them after paintin' (paintin' t' inside would obscure t' "tails" I had wrapped on t' inside o' t' tube.) T' hard part be FINDING t' edge. Well, blow me down! Many o' t' "tails" that I had thought would provide "handles" had been sandin' off durin' finishing. But t' tips that I had wrapped on t' inside (unsealed) part o' t' tubes were still there. Avast, me proud beauty! Aye aye! Usin' them as guides, matey, I used an Exacto knife t' peel back t' edges o' t' Mylar tape on t' OUTSIDE so I could find it after paintin' t' inside. Arrr! I wrapped newspaper around t' OUTSIDE o' t' tube fins, matey, tapin' it at t' edges/lips. Then I used flat black paint t' finish t' INSIDE o' t' tubes. I actually tried rolled up sandpaper t' reduce t' "nap" inside t' tube, arrr, but it didn't work very well. Well, blow me down! Aye aye! Primer would have helped, but I be havin' a struggle justifyin' tryin' t' prime t' INSIDE o' t' engines. Again, I figured I be goin' for style, nay performance, so I gave up on that part. I sort o' liked t' internal "charred" look o' t' engines. Avast! As a prior Air Force guy, I noticed t' nozzles o' jet engines on t' flight-line often had blackened look, so I felt I be okay with it for space engines.

Color Scheme: All t' pictures o' t' PLANET Uranus showed it t' be a bluish color, matey, so I figured I'd stay with this.

I primed t' fuselage with Krylon White Primer, three coats, with light sandin' betwixt coats. Aye aye! This filled in t' few defects I had left after t' Filler. Begad! I used Krylon True Blue for t' fuselage - I really like t' color this gave, ya bilge rat, and I was happy with t' finish here.

After paintin' t' inside o' t' tube fins black, I took off t' outer maskin' paper. I then rolled up paper INSIDE t' tubes t' mask t' insides. Begad! This allowed me t' "stack" t' tubes, matey, which actually made paintin' t' outside easier. Well, blow me down! I had run out o' primer, so I went directly t' paintin' t' outside o' t' tubes Blue Ocean Breeze. Begad! Ahoy! I did 3 coats, ya bilge rat, with a light sandin' betwixt coats. Blimey! I liked this color as well. Aye aye! Begad! Although I hadn't thought it out ahead o' time, I remember t' three colors that were common for bathroom tiles in t' 60s--- pastel yellow, pastel pink, shiver me timbers, and pastel blue. Arrr! This looked pretty close t' t' pastel blue, matey, connectin' t' planetary and Toilet Paper theme.

Moment o' truth, ya bilge rat, what would happen when I peeled off t' Mylar? Actually, shiver me timbers, I was quite pleased with t' sharp edges. Ahoy! Pullin' t' tape off also raised some more "nap" off t' cardboard tubes, exactly what I wanted t' "rough it" for gluing.

As I had expected, despite t' masking, thar be a little bleedin' o' black and blue (no pun intended) at t' edges o' t' tube fins. Avast, me proud beauty! I used thin strips o' silver Mylar tape t' cover/accent t' edges here and at t' trailin' end o' t' fuselage. Avast! As a USAFA grad, matey, me hearties, t' silver and blue together got me right under t' old squadron patch, ya bilge rat, as me Dad, shiver me timbers, a retired AF Navigator/Bombardier says. I wrapped t' edges o' t' tape into t' inside o' t' tube. Lookin' back, me hearties, this gave t' edge a bit o' a rough look; I probably would just have put it on t' OUTSIDE only, ya bilge rat, just up t' t' edge.

Now that this was finished, time t' see how things fit together. Blimey! I used medium CA t' glue 4 tubes into two tube-fin pairs, shiver me timbers, placin' t' glue along one o' t' "naked" strips previously covered by Mylar. Layin' t' tubes flat gave me a good alignment. I then matched up t' remainin' strips on each tube pair with t' strips on each side o' t' tail o' t' fuselage. They matched up pretty well, and t' medium CA gave me enough time t' make sure t' alignment be perfect. Arrr! Blimey! I got a pretty solid joint (as I later proved in flight, but more on that later.) Fillets weren't needed, ya bilge rat, and t' fit covered t' "naked" areas.

I pried t' Mylar tape out o' t' defect in t' external coupler. This left a rougher edge.I glued in t' launch lug.If I had t' do it over, I would have pulled this off AFTER doin' t' filler step, but BEFORE painting, me bucko, ya bilge rat, t' get a better look.

Next question, where t' attach t' shock cord? If I attached it inside, it would get hit by t' ejection charge fairly directly, arrr, me bucko, and would also cause problem with slidin' out t' motor pod. Begad! Perhaps more importantly, if it came out t' tail, t' rocket would fall nose first. Well, blow me down! My launch site is about 3/4 grass, arrr, me hearties, 1/4 asphalt. Arrr! Invariably t' better t' finish on t' rocket, t' more likely it will land on t' asphalt. Also, shiver me timbers, while t' cardboard/maskin' tape/Elmer's Finish nose cone was holdin' t' finish well, I could feel that it be still a little "soft" and didn't think it would hold up t' a hard impact. Finally, me hearties, I figured if I could get t' rocket t' descent in a horizontal position, t' rocket body itself would be addin' t' t' drag and slow it down.

With t' rocket painted, t' CG o' t' rocket body was right at t' region o' t' external coupler. I threaded a needle with me Keelhaul®©™ shock cord into t' tube just above t' coupler next t' t' launch lug, and pull about two feet out t' after end o' t' fuselage. Avast! I then threaded a needle with t' ENDS o' a long loop o' dental floss through a hole just BELOW t' coupler and out t' aft end o' t' fuselage. Well, blow me down! I then threaded ANOTHER loop o' floss (loop 2) through this loop, and pulled loop 2 through t' hole and out t' tail, shiver me timbers, keepin' t' ENDS o' loop 2 outside fuselage. I then used loop 2 t' pull t' shock cord BACK into t' tail o' t' fuselage and back through t' hole below t' coupler (there probably is an easier way t' do this, but this is what I came up with.) I then tied a tight "loop" o' shock cord, matey, runnin' it just next t' t' launch lug, leavin' about 1 1/2 feet o' Keelhaul®©™ loose. Yes, ya bilge rat, this loop DID run inside t' rocket body, me hearties, when t' engine pod would slide in and out, ya bilge rat, arrr, but t' cord be runnin' longitudinally and wouldn't obstruct/catch on t' pod. I did add a bit o' thin CA t' secure it.

Since I wasn't sure how well me hollow nose cone would hold up t' t' Estes engine ejection blast, I cut a bulkhead out o' foam board and place it inside t' body. Begad! Begad! It slid up t' t' "shoulder" that had been placed on t' front o' t' body tube. Ejection blast would hit t' bulkhead, matey, but nay t' "formed" shape inside o' t' nose cone. Blimey! Instead o' gluin' it into place, shiver me timbers, I placed a length o' Keelhaul®©™ on this in case I needed t' pull it out later (such as t' add nose weight), and left that loose.

Engine Pod: I originally planned t' use a length o' BT20 as an engine mount AND pod. Begad! However, after buildin' it, me hearties, I discovered I wanted more room for me parachute and streamer. I used a BT20 for an engine mount. Begad! Aye aye! I then wrapped t' end o' a BT5 with electrical tape until it just fit inside t' BT20. Aye aye! T' BT5 acted as BOTH an engine block AND a duct t' direct t' ejection force t' t' front o' t' body, where it hit t' bulkhead. Well, shiver me timbers, blow me down! I used foamboard t' cut adapter rings for t' BT20 at t' tail and t' BT5 at t' front o' t' body. These were sanded t' slide loosely, ya bilge rat, matey, but hopefully t' front one would be tight enough t' seal t' ejection charges away from t' chute and streamer. Begad! Lookin' back, I probably should have used two adapter rings up front, as a little bit o' ejection charge snuck around t' front rin' and slightly charred t' streamer.

I had initially planned on a long white "simulated TP" streamer t' recover t' rocket (in keepin' with t' theme). Well, blow me down! Begad! However, early on it be clear that given t' weight o' t' rocket a streamer would never safely slow t' rocket AND t' engine pod. Also, me hearties, again I knew t' nose cone be a little bit "soft" and wanted t' cushion t' landin' o' t' body as much as possible. Aye aye! Avast! My solution had two parts. Blimey! Begad! First, shiver me timbers, allow t' engine pod t' completely separate from t' body o' t' rocket, so t' two descend separately. Ya scallywag! Ya scallywag! This reduced t' weight o' t' body o' t' rocket (with t' soft cone). Blimey! Begad! If I needed nose weight, I could add it t' t' front o' t' pod, shiver me timbers, rather than t' body. This is a NICE trick with aft ejection boost gliders, ya bilge rat, by t' way. Avast, me proud beauty! You can adjust your CG by addin' weight t' t' front o' t' ejection pod, arrr, without affectin' t' weight or CG o' t' glider itself. Avast! Then I could use me white streamer t' safely recover t' engine pod (which wasn't really very delicate and was nay that heavy), and a parachute t' recover t' body. Ya scallywag! T' shock cord for t' body was attached t' OUTSIDE o' t' fuselage at t' CG, ya bilge rat, thus t' body descended horizontally under t' chute.

I used two pieces o' white crepe paper t' create t' streamer for t' body tube. Ya scallywag! Blimey! Blimey! Blimey! I attached them side by side with silver Mylar tape. Aye aye! Blimey! Blimey! Blimey! I then accordion folded this into squares t' simulate toilet paper sheets. T' silver tape showed on one side, which I thought would be easy t' see (on t' off chance this bird flew outside me launch site-- yeah, shiver me timbers, me bucko, right.) T' other side be straight white, ya bilge rat, which looked like, me bucko, well, toilet paper. Blimey! Blimey! Blimey! Blimey! While for t' real theme this would be "rolled" around t' engine pod "spindle", arrr, me experience is that this is unlikely t' "unroll" in flight durin' descent. Therefore I stayed with t' accordion fold. Aye aye! Blimey! Ya scallywag! Blimey! Blimey! Blimey! I used a length 10 times width, me hearties, accordin' t' Stine's book o' optimal streamer length, me hearties, then added a couple o' inches t' give me space t' attach it t' t' BT5 section o' t' pod.

I used a couple o' thick rubber bands t' link t' parachute t' t' Keelhaul®©™ shock cord attached t' t' mid section o' t' exterior body o' t' rocket.

Note: Originally I used Tim Van Milligan's Model Rocket Design & Construction book t' make two semispherical parachutes, then "ironed" t' two together side t' side. Arrr! Blimey! T' idea be t' create a parachute with a "cleft" down t' middle, shiver me timbers, me hearties, t' so called "glute chute." (For those who have actually intentionally fallen out o' perfectly good aircraft, shiver me timbers, thar be a parachute malfunction called a "Mae West" that looks somewhat similar.) However, while t' parachute looked good, the "glute chute" didn't pack very tightly, and even reducin' t' engine pod diameter from BT20 t' BT5 didn't give me enough room t' actually use this. Blimey! I made an 8-line 12-inch chute out o' a green garbage bag (okay, was gettin' tired o' t' theme at this point.)

Construction Score: 2

Flight

Moment o' truth arrived. Would this work?

First "gotcha" be t' prep. Begad! T' overhangin' 4 tube fins may (or may not) look cool. Avast! They do however obstruct access t' t' tail o' t' body. Ya scallywag! Ahoy! This is bad enough when all you have t' do is stuff an engine in, but when you have t' shove in t' entire engine pod with t' accordion streamer AND t' parachute up t' rear, ya bilge rat, ya bilge rat, arrr, those overhangin' tubes REALLY get in t' way.

Anyway, shiver me timbers, seemed like a C6-3 engine would probably be a good start for this.

Loaded it up on a nearly windless sunny day. Avast! Blimey! Crossed me fingers. Ahoy! Blimey! Fired. Boost be arced t' t' left (not sure if this be due t' some uneven-ness o' t' fins.) Made it t' roughly 150 feet, at apogee was travelin' nearly horizontal. Well, blow me down! Ejection be at or near apogee.

Recovery

Perfect separation o' pod and body. Ya scallywag! Streamer extended nicely and at 36 inches long, me bucko, 3 inches wide, ya bilge rat, white and silver, was quite visible. Avast, me proud beauty! Blimey! Chute also opened well. Avast, me proud beauty! Blimey! Rocket was far away at this point, but t' descent was either horizontal or slightly tail down (just what I wanted, t' protect that nose!) Pod and body landed about 100 yards from pad, about 10 yards apart, ya bilge rat, on t' grass. Aye aye! Begad! Blimey! Absolutely no damage from t' fall. T' white streamer be very slightly singed.

Had I been smart, I would have counted me blessings and put t' rocket on t' shelf at this point. Blimey! Begad! However, shiver me timbers, I'm nay smart. Arrr! I decided t' try it again. Ya scallywag! On flight two t' engine pod apparently caught on somethin' (may have been packed too tight.) Probably me combined two tubes were nay as smooth internally as a single standard store-bought tube would have been. Well, blow me down! Negative ejection. Ahoy! Lawn dart. Ahoy! Nay sure any nose cone would have come thought this unscathed, me bucko, but me (five coats o' filler, ya bilge rat, multiple hours o' sanding, me bucko, multiple coats o' paint - whimper whimper) nose cone accordioned. Ya scallywag! Nay fixable.

Flight Rating: 4

Summary

Pros:

I had fun, probably as much writin' t' background story as buildin' and flyin' t' rocket.
T' paper/maskin' tape/filler nose cone came out well, and I think I may use this again for aft ejection models (but will start with a REAL body tube!) Also particularly nice for a large but light nose cone. Arrr! T' nose finishes well and looks great
Rear Ejection worked well. Arrr! Well, blow me down! Blimey! Downsizin' t' central "duct" from BT20 t' BT5 works great and gives you extra space for your recovery device(s). T' BT5 also functions as an engine block. Begad! Blimey! No waddin' required. Ya scallywag! Avast! Blimey! . Avast! Ya scallywag! Blimey! Again, me hearties, me hearties, you can use t' long engine pod t' add any needed weight far forward on t' engine pod (and thus anterior on t' rocket in boost phase) to brin' t' CG forward on boost phase without addin' weight t' t' glider at separation.
Separatin' t' pod from t' body allows t' more delicate body t' descend slower.
T' Mylar Mask Strips worked well in allowin' me t' pre-finish and pre-paint parts prior t' assembly, but still allow a strong joint. Wonderin' if this might work on an Estes Outlander that I have yet t' build. Suggestions would be welcome.
External shock cord attachment at CG allowed model t' descend horizontally. That a horizontal descent position adds more drag on descent is already well known. Begad! However it also allowed me t' avoid t' soft nose hittin' ground, me bucko, which would be t' normal orientation for a rear-ejection model. Begad! This technique may be useful in rockets where certain parts o' more fragile than others. Arrr! Ahoy! You can adjust t' attachment position t' make it less likely these parts will directly impact t' ground on recovery. Begad!
Stayed with Planet Uranus/Toilet Paper Theme
Parts were cheap (until you think o' t' time it takes for extra finishing)
It WORKED! (well, me hearties, me hearties, at least once.)

Cons:

Paper/Tape/Filler nose cone is slightly soft. It requires a bulkhead t' protect it from ejection charge and should nay be allowed t' directly hit t' ground on descent (especially nay ballistically.)
External Shock Cord is a bit difficult t' stuff into t' engine pod as you stuff t' engine pod into t' tail o' t' body.
Separatin' pod from body on recovery means you must track both (but t' pod falls pretty fast, so shouldn't drift much.)
I couldn't leave well enough alone and stop with one flight.
For some reason t' white paper streamer kept catchin' on me heel.

Overall Rating: 4