Scratch USS Moebius Original Design / Scratch Built

Scratch - USS Moebius {Scratch}

Contributed by Todd Mullin

Manufacturer: Scratch

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I loved EMRR's new "Spaceship Design Contest", me bucko, but in t' beginning, me bucko, me bucko, me hearties, I wasn't excited by any o' t' designs. Avast, arrr, me proud beauty! But, ya bilge rat, over t' weeks that followed, me hearties, I rotated t' pictures on me desktop wallpaper and studied each for a few days and finally settled on this design. Arrr! Ya scallywag! I thought that t' outboard motors would be an interestin' challenge that I had nay tried before. Well, blow me down! This design reminds me o' t' look o' t' ships o' Star Trek, though somewhat "lower tech" looking. Avast, me proud beauty! Probably around t' time o' t' "Enterprise" series and an early Star Fleet tug or supply ship from its looks. Begad! Workin' with that line o' thought, matey, as many o' t' ships in t' Star Trek universe are named after famous scientists and scholars, shiver me timbers, I decided t' name this rocket t' USS Moebius.

I started out t' design process by firin' up me handy-dandy copy o' Rocksim. I got t' basic model built and lookin' pretty good, I thought. Ahoy! However, thar be one little problem... Ya scallywag! Rocksim said it be totally unstable even with several ounces o' nose weight! At this point, I decided t' go ahead and build t' rocket that, shiver me timbers, matey, shiver me timbers, with me many years o' experience, I be pretty sure would be stable.

I decided that I would use an old Estes Fat Boy nose cone that I had kickin' around after me last Fat Boy lost it's match with gravity. Begad! This provided t' scale for t' design and t' rest was scaled t' look proportional t' t' picture. Well, blow me down! I decided t' keep t' design as simple as possible and pop t' nose cone on each nacelle instead o' tryin' t' passport t' ejection charge t' push out t' main nose cone. Due t' t' naggin' feelin' in t' back o' me head created by Rocksim, I decided t' go with 13mm motors instead o' t' larger 18mm t' cut back t' weight on t' tail end as much as possible.

Right side

This rocket provided me with an interestin' new challenge as well. Ya scallywag! T' get t' nose cones for t' nacelles t' look right, shiver me timbers, I would either need t' use a BT-5 stuffer tube inside o' t' BT-20 nacelles t' get t' correct look, me bucko, or try t' turn t' cones. Arrr! I up until this point had been highly intimidated by t' though o' tryin' t' turn cones for myself. For some reason, t' process seemed much more dauntin' than it actually (if you'll pardon t' pun) "turned" out t' be! I cut a chunk o' balsa t' 1"x1"x1" and CA'd a piece o' hard wood dowel into one end. Begad! Avast! I chucked this into me drill after it cured and locked t' drill in t' "on" position. I let t' drill rest on t' ground and held t' dowel as it turned (I'd recommend gloves for this...friction burns are nasty...) and used some 80 grit paper t' slowly round t' balsa into shape. Avast! Avast! T' first one came out amazingly perfect! I was floored! T' came t' harder part.... Ya scallywag! Makin' three more that were identical.... Begad! Heady with me initial success, it took a couple extras t' get four that were suitably close enough for use. Aye aye! Begad! If you have nay tried this because it seems t' "scary", me hearties, give it a shot. Ya scallywag! Avast, me hearties, me proud beauty! T' process is reasonalby simple t' grasp, but it is definitely an artform. Give it a little practice and it is really rewarding!

I also had t' turn t' tailcone for t' Moebius as well. Well, blow me down! This was somewhat easier as I was able t' trim t' diameter o' t' balsa t' match t' tube before I started turning. After turning, I glued t' cone flush without it havin' a shoulder. It seems t' be sturdy enough t' survive without t' extra weight that t' shoulder would have added.

Tall

T' rest o' t' build be fairly straight forward. Well, blow me down! I tacked t' fins t' t' nacelles with CA and Tite-bond, me bucko, filletin' after t' root bond had cured. Aye aye! I eyeballed t' alignment o' t' fins onto t' main airframe since me fin alignment guide wouldn't fit under t' outboard pods, ya bilge rat, me hearties, arrr, usin' t' same gluin' technique. I finished up where I normally start, buildin' and insertin' t' mini-motor mounts into t' pods.

At this point, arrr, arrr, I decided it would be a good time for a swin' test t' make sure that I be goin' t' have a rocket t' flew in straight lines instead o' loops! Blimey! With a couple o' ounces o' sand glued into t' front o' t' Fat Boy cone, ya bilge rat, arrr, t' rocket seemed stable enough for flight! Blimey! Nice t' see that I haven't lost me eye for stability, matey, me bucko, even though t' software said otherwise....

I took a page from t' Master o' t' Dark Art o' Rocketry, arrr, Shrox, t' add t' details t' t' nose...Pin' pong balls! I cut t' ends off a couple o' balls, me bucko, as a full half o' a ball be much too large for t' look o' t' design. Begad! I had a couple o' old Alpha III cones in me parts box, me hearties, so I halved them and trimmed them down t' about a third o' t' length so that they would match up nicely with t' pin' pong balls. Gluin' these t' t' airframe helped disguise t' seam betwixt t' body and t' nose somewhat.

I filled t' seams with Elmer's Fill-n-finish, arrr, me bucko, sanded and primed with Kilz and sanded again. Ahoy! Avast! T' tailcone got a coat o' Rust-o-leum Metallic Blue and t' airframe got a coat o' gloss grey. After maskin' t' grey stripes, I sprayed t' whole model with Rust-o-leum Metallic Black. Blimey! T' design for t' contest had a bit o' a pixelated pattern t' t' lighter grey areas, so I laid a piece o' loose weave fiberglass over t' grey areas and sprayed them with t' metallic black t' give them a little bit o' t' texture from t' image.

Back side

T' day o' t' launch, shiver me timbers, I had decided t' nay tempt t' wrath o' t' Rocket Gods and didn't want t' fly t' rocket in it's finished paint. Ya scallywag! It flew in primer only... Arrr! Pretty rockets make ugly flights!

My initial flight be on 4 A10-3T's. I loaded t' motors up and installed t' igniters with and borrowed a whipclip from a buddy. Blimey! All four motors lid and it jumped into t' sky perfectly thanks t' t' high initial thrust spike o' t' A10's. Begad! Avast, me proud beauty! All four nosecones popped in series, matey, much t' t' delight o' several children who were lookin' on. I had installed two streamers and a parachute, ya bilge rat, leavin' one o' t' cones t' just pop. Ahoy! Begad! This brought t' model down reasonably quickly, me hearties, but with no damage as t' flight be nay very high and our launch field here in San Diego is sand.

Lift-offI waited until another day t' get me additional flight in. Avast, matey, me proud beauty! Both me second and third flights were near disasters. Only 2 or 3 o' t' 4 motor lit on these flights. Blimey! Ahoy! With t' reduction in thrust, t' model was terribly underpowered, arrr, barely clearin' t' rod on t' 2 motor burn. Avast! Begad! At this point, I had burned through most o' me supply o' A10-3t's, so I loaded only two on t' next flight as well as 2 A-10PT's! This one lit perfectly, me bucko, but seemed t' nay fly quite as high as t' first flight had. Avast, me proud beauty! Well, blow me down! After another failled flight, me bucko, with this motor combination, shiver me timbers, I switched t' me final flight configuration, me hearties, 2 A10-3T's and 2 A3-4T's. Begad! Luckily, as these were t' last mini-motors that were left in me flight box, matey, all t' motors lit. Begad! Avast, matey, me proud beauty! This combination was again underpowered. Begad! My thought had been that it would get more altitude because o' t' longer burn o' t' A3's, shiver me timbers, but without t' initial thrust spike from 4 A10's, me bucko, ya bilge rat, t' flight barely ejected before impact.

I enjoyed t' experience o' buildin' this rocket because o' t' challenge o' it's outboard cluster and havin' t' learn t' new skill o' turnin' cones. Arrr! Blimey! Overall a very satisfyin' experience. Avast! I am goin' t' continue flyin' t' Meobius after t' contest, ya bilge rat, but in a modified configuration. I am goin' t' glue in t' nacelle nose cones. Arrr! Well, blow me down! Lightin' all 4 motors is more o' a challenge than I would rather deal with every time I want t' fly it. Ahoy! Since t' tail cone is only surface glued t' t' end o' t' main airframe, it should be easy t' remove. Aye aye! I'm goin' t' install a central 24mm motor mount that will aft eject, as t' nose details are glued securly over t' seam at t' front, makin' a standard ejection impossible.

 

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