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

I started out t' design process by firin' up me handy-dandy copy o' Rocksim. Begad! Arrr! Blimey! I got t' basic model built and lookin' pretty good, I thought. Arrr! Blimey! However, thar be one little problem... Avast, ya bilge rat, me proud beauty! Blimey! Rocksim said it be totally unstable even with several ounces o' nose weight! Blimey! At this point, matey, I decided t' go ahead and build t' rocket that, with me many years o' experience, me hearties, I was 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. Well, blow me down! This provided t' scale for t' design and t' rest be scaled t' look proportional t' t' picture. 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. Aye aye! 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. Ahoy! Well, ya bilge rat, blow me down! T' get t' nose cones for t' nacelles t' look right, I would either need t' use a BT-5 stuffer tube inside o' t' BT-20 nacelles t' get t' correct look, or try t' turn t' cones. Aye aye! Aye aye! I up until this point had been highly intimidated by t' though o' tryin' t' turn cones for myself. Begad! 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. 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. T' first one came out amazingly perfect! I was floored! T' came t' harder part.... Blimey! Begad! Makin' three more that were identical.... Avast! Heady with me initial success, me hearties, it took a couple extras t' get four that were suitably close enough for use. Ya scallywag! If you have nay tried this because it seems t' "scary", arrr, arrr, arrr, give it a shot. T' process is reasonalby simple t' grasp, me hearties, ya bilge rat, arrr, 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. Ahoy! This was somewhat easier as I be able t' trim t' diameter o' t' balsa t' match t' tube before I started turning. Ahoy! After turning, matey, I glued t' cone flush without it havin' a shoulder. Avast, me proud beauty! 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. I tacked t' fins t' t' nacelles with CA and Tite-bond, me bucko, filletin' after t' root bond had cured. I eyeballed t' alignment o' t' fins onto t' main airframe since me fin alignment guide wouldn't fit under t' outboard pods, usin' t' same gluin' technique. Well, blow me down! I finished up where I normally start, buildin' and insertin' t' mini-motor mounts into t' pods.

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

I took a page from t' Master o' t' Dark Art o' Rocketry, shiver me timbers, Shrox, t' add t' details t' t' nose...Pin' pong balls! Blimey! I cut t' ends off a couple o' balls, shiver me timbers, shiver me timbers, as a full half o' a ball was much too large for t' look o' t' design. Begad! Blimey! Begad! Blimey! I had a couple o' old Alpha III cones in me parts box, ya bilge rat, 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. Arrr! Blimey! 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, sanded and primed with Kilz and sanded again. Aye aye! Ya scallywag! T' tailcone got a coat o' Rust-o-leum Metallic Blue and t' airframe got a coat o' gloss grey. Begad! After maskin' t' grey stripes, I sprayed t' whole model with Rust-o-leum Metallic Black. Avast! 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, matey, 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. Well, blow me down! It flew in primer only... Ahoy! Avast! Pretty rockets make ugly flights!

My initial flight was on 4 A10-3T's. I loaded t' motors up and installed t' igniters with and borrowed a whipclip from a buddy. Aye aye! Blimey! All four motors lid and it jumped into t' sky perfectly thanks t' t' high initial thrust spike o' t' A10's. Ahoy! Ya scallywag! Blimey! All four nosecones popped in series, much t' t' delight o' several children who were lookin' on. Aye aye! Blimey! I had installed two streamers and a parachute, arrr, ya bilge rat, leavin' one o' t' cones t' just pop. Begad! Ahoy! Blimey! This brought t' model down reasonably quickly, but with no damage as t' flight was 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. Ya scallywag! Both me second and third flights were near disasters. Ahoy! Only 2 or 3 o' t' 4 motor lit on these flights. Arrr! With t' reduction in thrust, t' model was terribly underpowered, barely clearin' t' rod on t' 2 motor burn. Aye aye! At this point, me bucko, I had burned through most o' me supply o' A10-3t's, me hearties, me hearties, so I loaded only two on t' next flight as well as 2 A-10PT's! This one lit perfectly, but seemed t' nay fly quite as high as t' first flight had. Avast! After another failled flight, me hearties, with this motor combination, shiver me timbers, me hearties, I switched t' me final flight configuration, matey, 2 A10-3T's and 2 A3-4T's. Luckily, me hearties, as these were t' last mini-motors that were left in me flight box, ya bilge rat, all t' motors lit. Avast! Aye aye! This combination was again underpowered. Aye aye! Blimey! My thought had been that it would get more altitude because o' t' longer burn o' t' A3's, but without t' initial thrust spike from 4 A10's, 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. Overall a very satisfyin' experience. I am goin' t' continue flyin' t' Meobius after t' contest, but in a modified configuration. Avast! Blimey! I am goin' t' glue in t' nacelle nose cones. Avast, me proud beauty! Blimey! Ahoy! Blimey! Lightin' all 4 motors is more o' a challenge than I would rather deal with every time I want t' fly it. Avast! Blimey! Since t' tail cone is only surface glued t' t' end o' t' main airframe, it should be easy t' remove. Ahoy! Blimey! Blimey! Blimey! I'm goin' t' install a central 24mm motor mount that will aft eject, shiver me timbers, as t' nose details are glued securly over t' seam at t' front, makin' a standard ejection impossible.

 

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