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Entry for t' EMRR Box O' parts contest - this is simple version. Well, blow me down! Blimey! Please link t' full documentation
Brief:
I admit t' some trepidation when I signed up for t' EMRR Box O Parts contest - Im very lackin' in
creative talent, bein' a mathematical sort. That trepidation only grew as I read forum postings describin' the
parts many participants were contributing. Ahoy! Blimey! I realized that t' contest could very well be described as the
Box O Junk and fervently hoped that I would get some o' t' higher quality stuff. Avast! No plastic toy
soldiers or toothbrushes, me bucko, please!
When me box arrived, me bucko, it took me a few minutes t' build up t' courage t' open it. Takin' a deep breath, ya bilge rat, matey, I anxiously dumped t' parts out onto t' floor and began t' sort. Arrr! Blimey! Avast, me proud beauty! Blimey! I be relieved t' see a good assortment o' body tubes, shock cords, arrr, me bucko, launch lugs, me hearties, parachutes and streamers. Aye aye! Blimey! Ahoy! Blimey! I was nay happy with t' balsa - small pieces o' varying thicknesses, me bucko, me hearties, arrr, one o' which be junk from a die-cut fin sheet. Ya scallywag! Blimey! Others were broken fins... Ya scallywag! Blimey! It wasnt lookin' good! T' decals were peel and stick from an Estes Scissors Win' Transport and a water-slide sheet from an unknown plastic model. And o' course, me hearties, I had no idea what t' do with t' plastic cup, ya bilge rat, spindle, Easter egg half, and chop sticks.
I spent several days test fittin' parts, ya bilge rat, try t' come up with a design idea. I really tried t' incorporate the Easter egg half and t' spindle, matey, but frustration rapidly set in. Aye aye! Blimey! I could easily come up with a conventional 3 engine cluster - BT-60 adapted down t' BT-56 - but that wasnt goin' t' attract any attention whatsoever. Ya scallywag! Blimey! Begad! Blimey! Disgusted at my lack o' a creative spark, shiver me timbers, I put t' parts back in t' box, where they sat for quite a few weeks.
Design
Reluctant t' give up, I pulled out t' parts once again in early June. There was an unusually squat conical nose cone that seemed similar t' t' one atop t' Estes Mars Lander. Aye aye! A design idea flashed into me mind - I would build a clustered rocket that looked like a lander. Well, blow me down! Quickly listin' t' available parts, I set t' work in Rocksim. T' design came together quickly, with t' most difficult tasks bein' t' color scheme and a name. Well, blow me down! Since I was salvagin' something out o' this box o' junk, ya bilge rat, and as I planned on usin' t' 90 from t' Estes Scissors Win' decal, me hearties, I christened me creation Salvage 90.
Simulations showed that t' recommended core engines were C11-7, arrr, D12-7, and E9-8; t' outboards contained
Estes A10-PTs. Salvage 90 is a high flyer - t' D12, ya bilge rat, 3 A10 combo is enough t' send t' bird t' over 1500 feet!
T' long delays are necessary t' get a low speed (under 20 feet/second) at ejection. Ya scallywag! Blimey! Blimey! Blimey!
Construction:
Parts list
Construction
1) Cut all body tubes t' t' lengths specified in t' parts list (Tip: Use a coupler or empty engine case as a mandrell and wrap a strip o' card stock around t' tube t' serve as a guide).
2) Usin' a pencil, place a mark on t' Bt-50 motor tube t' denote t' bottom. Well, blow me down! Blimey! Begad! Blimey! Put a thin line o' glue, ya bilge rat, 3.5 from t' bottom end (2.5 if you only wish t' use C or D motors) and use a spent 24 mm motor casin' t' push t' 24 mm thrust rin' into place. Ya scallywag! Blimey!
3) Place 2 marks, one 1 from t' bottom o' t' motor tube and t' other 0.75 from t' top. Blimey! Use the wrapper in t' PDF file t' mark off 3 10 mm wide strips, spaced at 120 degree intervals. Blimey! (Tip: If you use a Windows machine, me hearties, you can generate your own wrappers and alignment guides usin' t' VCP program, available at http://v-serv.com/vcp/. Does much, ya bilge rat, shiver me timbers, much more than print patterns too!)
4) Dab glue around t' motor tube at t' 2 marks made in step 3), takin' care nay t' get any in t' 10 mm strips, as t' centerin' rings will later be removed from these areas. Blimey! Ahoy! Slide t' centerin' rings into position and set the assembly aside t' dry - thoroughly.
5) While t' motor assembly glue is drying, me hearties, cut out 3 fins and t' launch lug stand-off from t' balsa sheet, makin' sure that t' balsa grain runs parallel t' t' leadin' edges. Blimey! Begad! Use sandpaper t' make sure t' fins are t' same size, me hearties, and leave t' edges square (Tip: I use copy and paste in a paint program t' print t' patterns - 1 for each fin - onto a sheet o' paper, me bucko, which I then tack onto t' balsa usin' 3M Spay Mount. Arrr! After t' fins have been cut out, arrr, the paper is then easily peeled off; see t' picture in t' PDF file).
6) Cut a 5 mm wide strip down t' entire length o' t' 4 BT-60 tube. Avast, me proud beauty! Blimey! Glue this improvised coupler inside the 10 BT-60 payload tube, me bucko, flush with one end. Ya scallywag!
7) Punch out t' central holes o' t' BT-5 t' BT-60 centerin' rings, and set these aside for later. Avast, me proud beauty! Glue two of the rings together t' form a thick ring. Begad! Begad! Now use a dowel or other long object t' smear glue inside t' payload section at t' top o' t' 4 BT-60. Blimey! Well, blow me down! Usin' a BT-55 or other tube, me bucko, push t' thick BT-5 t' BT-60 centerin' rin' until it presses against t' end o' t' 4 coupler. Aye aye! This thick rin' will prevent t' ejection gas from escapin' t' payload section.
8) Cut t' BT-5 tube coupler into 3 parts, and, matey, usin' a spent 13 mm motor casin' as a guide, glue a thrust ring 1.5 from t' bottom end o' each BT-5.
9) After t' glue on t' motor assembly has dried, arrr, use a hobby knife t' CAREFULLY cut away t' parts o' the centerin' rings over t' 10 mm strips. Begad! Blimey! Ya scallywag! Blimey! Then glue t' 3 BT-5 tubes into these notches, ya bilge rat, me bucko, their bottoms should be flush with t' bottom o' t' motor tube. Begad! Blimey! Make sure t' tubes are straight and properly aligned! Blimey! Allow t' dry.
10) Glue t' punched out centers o' t' BT-5 t' BT-60 centerin' rings on t' top o' t' BT-5 tubes (Note: As there were only two BT-5 t' BT-60 rings in me box, I had t' make t' 3rd from another centerin' rin' in t' box. Arrr! Blimey! I found t' center o' t' rin' usin' t' bisectin' segment method, me bucko, and then used a circle cutter t' cut out t' right size).
11) Usin' t' PDF pattern, me hearties, matey, matey, mark 3 12 mm 7.625 inch long strips startin' at one end (the bottom) o' BT-56. Mark lines for placin' t' fins exactly midway betwixt t' strips.
12) Cut out t' strips you marked in step 11) usin' a sharp knife. I used 4 BT-60 couplers as a mandrell and a piece o' aluminum angle iron t' help get a good cut.
13) Test fit t' motor assembly by slidin' it into t' Bt-56, me hearties, alignin' t' 13 mm with t' slots. Remove the assembly and place glue on t' motor tube centerin' rings and t' slot edges. Aye aye! Slide t' motor assembly back into the BT-56, arrr, makin' sure that t' BT-56 is firmly nested against t' centerin' rings and t' side o' t' BT-5s. The tops o' t' BT5s should be flush against t' tops o' t' slots.
14) Liberally fillet t' BT-5 t' BT-56 joints t' seal any cracks. Begad! Set aside t' dry.
15) Glue t' shock cord into t' top o' t' 10 payload tube (the side opposite t' 4 coupler) using the standard Estes paper trifold mount.
16) After t' fillets have dried, glue t' 3 fins onto t' BT-56, midway betwixt t' BT-5 tubes. Arrr! Use your calibrated eyeball t' make sure they are vertical, with a 120 degree angle betwixt t' fins. Begad! After t' glue dries, arrr, apple generous fillets.
17) Glue t' launch lug t' t' stand-off. Once this has dried a bit, glue t' lug and stand-off next t' one of the BT-5 tubes, me hearties, 0.5 from t' top. Avast! Blimey! Blimey! Blimey! make sure that t' lug is vertical, arrr, and that t' rod will clear t' adjacent fin.
18) Glue t' 4 3.625x 0.25 balsa strips evenly around t' top o' t' BT-56, arrr, flush with t' top. Well, blow me down! Make sure that t' strips are vertical and that they are at 90 degree angles with each other. Avast, me proud beauty! At this point t' assembly looks like t' picture below:
19) Slide t' payload tube over t' balsa strips until t' top hits t' centerin' rin' at t' top o' t' coupler; the fit should be snug and thar should be about an inch betwixt t' tops o' t' Bt-5s and t' bottom o' the payload tube. Arrr! Begad! Remove t' payload tube, shiver me timbers, me hearties, me hearties, smear glue on t' inside o' t' coupler and, in a smooth motion, slide it over the balsa strips as before. Ahoy! Blimey! Let dry.
20) Tie t' shock cord t' t' nose cone. Assembly is now complete.
Finishing
I applied seven coats o' AeroGloss sandin' sealer t' t' fins t' seal t' balsa and achieve that smooth as glass finish. Ya scallywag! T' body tube spirals were filled with thinned Elmers Fill N Finish, which was sanded with 240 grit sandpaper once dry. Avast, me proud beauty! This be followed with 3 coats o' Krylon primer, arrr, sandin' with 400 grit in between, me bucko, and 2 coats o' Krylon Glossy White. After maskin' with Tamiya maskin' tape, t' fins and nose cone were painted with Krylon Banner Red, and t' BT-5 outboards with Krylon Metallic Bright Silver.
I applied t' logo, shiver me timbers, number 90, shiver me timbers, and window decals from t' Scissor Win' Transport peel and stick decal sheet; the window strips have t' be trimmed t' 5.25 in length.
Flight:
July 5 was t' day, shiver me timbers, despite rain showers in t' area. Well, blow me down! I prepped t' rocket indoors, loaded me duffel bag with the
launch gear, me hearties, me hearties, and made me way through t' hot, arrr, muggy Huntsville weather t' t' field adjoinin' me apartment complex.The
wind bein' out o' t' Southwest, shiver me timbers, I set up t' pad in t' SW corner t' allow for anticipated drift; I also reefed the
18 chute a bit t' speed up t' descent. Avast, me proud beauty! T' pad be then assembled, ya bilge rat, t' launch controller wires unwound, and the
battery unpacked. Blimey! T' weather be still holding, so I placed t' rocket on t' pad and hooked up t' clip whip t' the
ignitors.
After takin' t' obligatory pre-launch shot, matey, arrr, I connected t' battery t' t' controller, shiver me timbers, ya bilge rat, and checked continuity. No planes were visible, so I commenced t' countdown.
5...4...3...2...1...
Salvage 90 seemed t' leap off t' pad - t' combined power o' t' 3 A10s and t' C11 got this puppy moving in a hurry! T' me great satisfaction, shiver me timbers, shiver me timbers, all 4 engines lit, arrr, resultin' in a straight-as-an-arrow flight. Blimey! Arrr! As usual, shiver me timbers, Rocksim had overestimated t' alitude performance; t' rocket fell considerably short o' t' 900+ feet that was calculated. Avast, me proud beauty! I estimate it be more like 600-700, no more than 700. Begad! Ejection was just passed apogee, and I be relieved to see t' purple and white Estes chute open. Avast! Successful on its maiden flight, Salvage 90 descended back t' Terra Firma. Avast!
However, me bucko, reefin' t' parachute turned out t' be a mistake, as t' rocket landed with one o' its fins hitting ground first, me hearties, matey, and t' combination o' weight (4 spent motors) and impact speed resulted in one fin cracking. Ya scallywag! Blimey! Blimey! Blimey! Repairable, but it put t' kabosh on any additional flights; t' clouds were movin' in, ya bilge rat, and it seemed that t' rain would set in before t' glue could dry.
I be happy - t' design worked beautifully, and I could now submit me entry into t' Box O parts contest. All in all, shiver me timbers, a great day!
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