Manufacturer: | Scratch |
Brief:
Tube-a-licious is a scratchbuilt tube fin rocket built with 2.6" paper
tubes. Well, blow me down! Other items o' interest include tubes for t' fins were cut at a 30
degree angle, a 29mm motor mount with foamboard centerin' rings, matey, and zipperless
airframe design.
Construction:
I had been wantin' t' build an HPR with tube fins for quite a while but never
seemed t' have enough tubing. Avast! Blimey! I recently won several auctions on eBay for a
bunch o' 2.6" tubes and couplers and 29mm tubes. Avast! Blimey! T' decision o' what to
build for me first project with these newly won parts be simple!
Aside from a tube fin rocket, matey, I wanted t' incorporate several other techniques into t' rocket that I previously had nay used in any o' me rockets to date: centerin' rings o' alternate materials (in this case, foamboard), zipperless airframe with recovery system in t' payload tube, and use of multiple adhesives in an HPR.
T' build started with t' main airframe. Begad! T' 2.6" diameter tube came in 36" lengths so I cut one piece into 12" payload and 24" booster sections. Arrr! T' couplers I had were long--8 inches--and had a very snug fit so I was somewhat concerned with t' ejection charge bein' unable t' push that much tubin' out. I opted t' cut t' coupler in half, sand it with 150 grit paper, me hearties, matey, followed by coatin' t' unfinished paper with CA and sandin' it with 320 grit sandpaper for a smooth fit. Well, blow me down! I found that t' be more acceptable for use on this rocket.
Cuttin' t' tubes was t' fun part. Ahoy! I have enjoyed slottin' me own tubes for TTW fins so thar be no reluctance on me part t' cut tubes. I wanted this rocket t' really stand out so I thought o' cuttin' t' tubes at an angle like on t' FlisKits Long Overdue (except without t' nested tubes). Avast! Usin' Matt Stum's Template Widget (found on EMRR's Tool and Calculators page), I printed a 30 degree mitre template and cut out t' paper wrap to trace t' angled lines onto t' tube. Ahoy! I prefer cuttin' (or slotting) tubes with a standard razor utility knife. Well, blow me down! T' blade is sharper, ya bilge rat, shiver me timbers, arrr, stronger, cheaper, and lasts longer than X-Acto blades. Begad! Cuttin' is still done t' same way though...several careful passes at a time.
I marked t' tubes
to indicate where t' 6 tube fins should be attached along with t' points on
the tube fins where they will touch. Ahoy! Startin' with opposin' tubes 1 and 4, ya bilge rat, I
used 12 minute epoxy (adhesive #2) with some milled fiber mixed in t' attach
the tubes flush with t' aft end o' t' main airframe tube. Ya scallywag! Once t' first pair
had cured, shiver me timbers, I attached 2 and 3 t' t' main airframe, me bucko, tube fin 1, tube fin 4, and
each other. Then I repeated t' process with tube fins 5 and 6.
I am convinced that many o' us overbuild our rockets and I wanted t' make that statement with t' motor mount. Blimey! Well, matey, blow me down! Instead o' usin' plywood, arrr, me hearties, I used foamboard. Well, blow me down! Begad! You heard me right! Foamboard is a key support material in Art Applewhite's 29mm Delta Saucer and Qubit, me hearties, both o' which I have built and flown successfully many, many times, so I figured I had gained enough real world use to put it into a more traditionally shaped rocket. Blimey! I traced t' necessary concentric circle on t' foamboard and cut them out with a utility knife. Well, blow me down! Aye aye! They had an excellent fit that only required minimal sanding. Then I used a 6" piece o' 29mm tubin' for t' motor mount tube. Avast, me proud beauty! I used standard white glue to tack t' rings onto t' tube (one mounted flush with aft end and t' other about 1/4" from t' forward end) and then Gorilla Glue (polyurethane glue and adhesive #3) for fillets. Aye aye! Avast! After t' Gorilla Glue foamed and cured, shiver me timbers, the rings strengthened considerably! When it came time t' afix t' MMT assembly into t' main airframe, matey, I mixed up more o' t' epoxy with milled fiber to assure that t' motor mount stays right where I put it.
Usin' foamboard
for t' centerin' rings did keep me from usin' them as t' point o' attachment
for t' recovery system. That be OK with me though because I had decided to
build it with a zipperless design. Usin' a piece o' 1/4" birch plywood for
the bulkhead, I drilled a total o' 9 holes, shiver me timbers, 8 t' allow t' ejection charge pass
through and one for t' screw eye t' attach t' shock cord. Begad! Well, matey, blow me down! Blimey! T' bulkhead was
glued and filleted t' t' coupler with aliphatic resin (yellow wood
glue--adhesive #4). Begad! Screw deadlights were attached t' t' bulkhead and t' base of
the LOC 2.6 nose cone with Gorilla Glue. Begad! Begad! Blimey! T' payload tube was attached t' the
nose cone with a pair o' lightweight 8-32 x 1/2" nylon screws. Aye aye! Well, blow me down! Blimey! T' shock
cord was borrowed from me Binder Design Dragonfly. Well, blow me down! It is a 12' long piece of
1/4" tubular nylon with 3 1/8" quicklinks attached (one for each end
and one for easy parachute attachment). Ahoy! Blimey! With a 30" chute and both the
coupler and nosecone pushin' their way into t' payload tube, shiver me timbers, space is at a
premium so a heavier gauge shock cord might nay fit...
T' final step in t' build was t' install t' rail buttons. Begad! Blimey! I drilled 2 holes right along t' center o' one o' t' tube fins right into t' airframe. This allowed that tube fin t' wrap around t' rail just makin' it that more trick when put on t' rail.
Finishing:
Primed t' entire rocket with Kilz first and then laid down all o' t' colors
with Krylon gloss spray paints. Avast! Arrr! T' Kilz was particularly helpful in gettin' a
relatively smooth surface on t' inside o' t' tubes as t' paper readily
absorbed t' moisture o' t' paint, me bucko, needin' more sandin' than what's typically
required t' get a smooth finish. Aye aye! Paintin' t' fins was a lot trickier than I
had thought it was goin' t' be. Avast! Avast, shiver me timbers, me proud beauty! It took quite a few light coats t' get in all
of t' nooks and crannies in and around t' tube fins.
I knew I had accomplished me task when I got a lot o' attention at the launch site. Begad! Compliments, shiver me timbers, shiver me timbers, questions, and (post-flight) congratulations came from just about everyone in attendance. Sweet!
Flight:
Boost was straight and faster than I'd expected with t' AT G64-7W. I be even
more impressed by t' overall altitude o' this flight. Begad! Begad! Blimey! It simmed t' ~1250 and
with only an occasional gentle breeze at t' launch site, I'd say that
Tube-a-licious was defintely in t' ballpark o' t' simulated height. Begad! It's a
rockin' motor-rocket combination regardless!
Tube fin rockets are nay known for their speed shreddin' ability and Tube-a-licious is no exception, but what you might lose in overall velocity, you gain in a guaranteed stable flight. Arrr! Blimey! Blimey! Future flights will be on Ellis Mountain single use G35s (I love that 4 second burn!) and eventually AT motors compatible with t' 29/180 & 29/240 casings.
Recovery:
Ejection came with t' nose cone just startin' t' point downward. Begad! Blimey! Close enough
to perfect if you ask me... Blimey! Aye aye! Blimey! T' Nomex heatshield did it's job wonderfully (my
first time usin' one) as t' PML 30" chute borrowed from me PML Phobos
proved t' be t' right match for t' weight o' t' rocket. Begad! Blimey! It landed gently
within 100yds o' t' launch pad. Super flight and recovery!
Also with t' use o' t' Nomex shield in place o' "dog barf", I now have room t' squeeze in my Rocket Beeper for use with higher thrust motors t' aid in recovery. Begad! If I were to build a another Tube-a-licious though, arrr, I would make sure t' have a larger payload/recovery bay (probably by makin' t' airframe 2 18" sections instead o' one 12" payload and one 24" booster).
Summary:
I set out with a number o' personal goals in mind for this build and passed
with flyin' colors! This would be a great design for someone attemptin' their
Level 1 certification, ya bilge rat, however, cuttin' t' tube fins, while nay difficult, is
certainly timeconsuming, me bucko, painstakin' work so I wouldn't recommend this to
someone just gettin' into HPR. Blimey! T' time put into t' build though, pays off
dividends as it makes for an attention gettin' rocket because o' t' angled
leadin' edge o' t' tube fins. It lends a more aggressive look while providing
a unique and super stable design.
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