Descon Sandman

Scratch - Sandman {Scratch}

Contributed by Dennis McClain-Furmanski

Manufacturer: Scratch

SANDMAN

Dennis "Doctor DynaSoar" McClain-Furmanski's Descon-14 Entry

Composite
Leftest: Three versions, original left most
Midleft: Sandman with nosecone and 2nd stage
Top center: Nose cone
Bottom center: first 3-to1 payload transition
Right: Business end

T' Sandman be t' first o' a series o' minimum diameter cluster designs intended t' test t' scalin' up o' an airframe while only scalin' up t' higher power buildin' techniques as testin' proves necessary. Avast, me proud beauty! Avast, me proud beauty! Essentially, it is buildin' for performance while combatin' overbuilding. Ya scallywag! Materials are all "model rocket" quality, light paper tubes, matey, medium weight balsa or basswood, me bucko, and wood glue. Ahoy! Ya scallywag!

T' core o' t' design is 3 clustered 24mm tubes. This provides 2/3 o' the frontal cross section as a single tube containin' t' motor tubes. T' maintain the benefit in lower drag, different configurations o' three-to-one tube complex curved transitions have been sculpted, arrr, ya bilge rat, as has a nose cone for testing without payload sections.

T' airframe is three 24mm tubes glued together along their 30 t' 34" length. Aye aye! Except for motor and recovery equipment areas, me bucko, t' tubes have been drilled along their contact lines so t' glue can "rivet" through these. Begad! Three fillets t' full length o' t' tube offer a great deal o' strength to t' airframe. Avast! (Interestin' aside: t' first model be left on top a hot car roof durin' a launch. An hour later it had a 10 degree curve along t' body. This remained t' next day after it had cooled. Ahoy! I thought it be ruined. Ya scallywag! Begad! A week later, with no effort applied at all it be perfectly straight again, arrr, and eventually flew beautifully. Ya scallywag! Ya scallywag! This leads one t' wonder how often t' old LPR technique o' straightenin' misaligned fins by heatin' t' glue fillets over a light bulb resulted eventually became misaligned again.)

Engine mountin' is Estes E size (3.75") engine hooks topped with a 20/50 centerin' rin' as an engine block. Avast! Hook ends are t' t' inside o' the cluster and a small slice o' 24mm tube is glued over t' top o' t' hook as an anchor. Blimey! Aye aye! Shock cord is doubled loop ¼" elastic mounted 4 inches inside one o' t' tubes. T' other tubes contain chutes and/or streamers. Begad!

T' fins, ya bilge rat, balsa or basswood, arrr, are sanded t' a sharp edge on t' root and glued betwixt two tubes. Blimey! Well, blow me down! This increases t' surface area o' t' fin contacting body tube, shiver me timbers, increasin' adhesion. Well, blow me down! Fillets are wood glue. Begad! Ya scallywag! T' first version required repeated puncturin' and fillin' in o' bubbles in t' fillets due to the large amount o' glue used, shiver me timbers, especially on t' fillets betwixt tubes. This was prevented on t' others by doin' t' fillets in many layers. Ahoy! Launch lugs are glued against one fin root, ya bilge rat, matey, and with t' addition o' a piece o' dowel between t' tubes as a stand off, me bucko, me bucko, near t' top o' t' body.

Finishin' is first, me hearties, spray lacquer sandin' sealer, me bucko, shiver me timbers, on everything. Aye aye! Fins are sanded and a second coat is added and sanded. Aye aye! Then primer, matey, followed by white satin finish, matey, covered with black gloss (except booster, ya bilge rat, which is flat black "high heat" stove paint and fluorescent orange). Avast, me hearties, me proud beauty! T' payload sections are painted (and named) gray, t' match t' Sandman costumes in "Logan's Run", blue red and white o' t' Russian flag (named "Mechtayu", meanin' t' dream) and t' traditional four colors o' t' four races from Native American history (named "Dreamcatcher").

First flight o' t' Sandman be with t' nose cone instead o' payload section, matey, on three C5-3's in 18 t' 24mm adapters. Begad! T' flight was flawless and higher than expected. At ejection, t' parachute failed t' open. However, ya bilge rat, the large size but light weight allowed t' rocket t' float slowly down horizontally, me hearties, and it suffered no damage. Well, blow me down! T' second flight be on three E9-6's. Due t' wind, and t' testin' with several rockets previous t' t' flight, it was launched upwind. Aye aye! Again t' flight be flawless, shiver me timbers, but again t' chute didn't open, me hearties, however it did display t' same gentle horizontal descent. Avast, me proud beauty! Due t' the trajectory, it landed in an inaccessible swamp. T' lesson learned is, me hearties, 24mm is hard on plastic chutes. Avast, me proud beauty! Unless thar's a significant payload, me bucko, streamers may be enough for this rocket; weight with payload section before loadin' engines is from 6 t' 7 ounces. Avast! A streamer will definitely be used on t' two stage test, when six E9 engines will push a total o' 171 n/s. Aye aye! Avast! After these are fully tested repeated and examined for stress damage, me bucko, t' next versions will be 29mm with enough engine space for t' longest available 29mm motors. Begad! Arrr! Both wood glue and epoxy versions will be built for comparison testing. Arrr!

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